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3.4 RISK CHARACTERIZATION
Risk characterization is the summarizing step of a risk assessment, which integrates the
hazard and exposure assessment components and presents overall conclusions. Risk
characterization typically includes a description of the assumptions, scientific judgments, and
uncertainties that are part of this process. There are several types of risk assessment ranging
from screening level to comprehensive, and differing according to framework: site-specific,
single chemical, or multiple chemical. This risk assessment is best described as a screening level
assessment of multiple chemicals identified as belonging to a particular use cluster (MHC) in the
PWB industry. This is a screening level, rather than a comprehensive risk characterization, both
because of the predefined scope of the assessment and because of exposure and hazard data
limitations. The intended audience of this risk characterization is the PWB industry and others
with a stake in the practices of this industry.
The focus of this risk characterization is on chronic (long-term) exposure to chemicals
that may cause cancer or other toxic effects rather than on acute toxicity from brief exposures to
chemicals. The focus is also on those health effects from chronic exposures that could be used to
measure risk. In addition, this risk characterization does not consider chemical persistence. The
Process Safety Assessment (Section 3.5) includes further information on chemical safety
concerns.
The goals of the PWB project risk characterization are:
• To present conclusions and uncertainties associated with a screening level health risk
assessment of chemicals used in the MHC process of PWB manufacture.
• To integrate chemical hazard and exposure information to assess risks from ambient
environment and occupational exposures from the MHC process.
• To use reasonable and consistent assumptions across alternatives, so health risks
associated with one alternative can be compared to the health risks associated with other
alternatives.
• To identify the areas of concern that differ among the substitutes in a manner that
facilitates decision-making.
This section contains a summary of the exposure assessment (Section 3.4.1), the human
health hazards assessment (Section 3.4.2), a description of methods used to calculate risk
indicators (Section 3.4.3), results (section 3.4.4), discussion of uncertainties (Section 3.4.5), and
conclusions (Section 3.4.6). Detailed exposure data are presented separately in the Exposure
Assessment (Section 3.2) and in Appendix E.
3.4.1 Summary of Exposure Assessment
The exposure assessment uses a "model facility" approach, where as much as possible,
reasonable and consistent assumptions are used across alternatives. Data to characterize the
model facility and exposure patterns for each process alternative were aggregated from a number
of sources, including PWB shops in the U.S. and abroad, supplier data, and input from PWB
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manufacturers at project meetings. Thus, the model facility is not entirely representative of any
one facility, and actual exposure (and risk) could vary substantially, depending on site-specific
operating conditions and other factors.
Chemical exposures to PWB workers and the general population were estimated by
combining information gathered from industry (Workplace Practices Survey and Performance
Demonstration data, MSDSs, and other available information) with standard EPA exposure
assumptions (e.g., for inhalation rate, surface area of dermal contact, and other parameters). The
pathways identified for potential exposure from MHC process baths were inhalation and dermal
contact for workers, and inhalation contact only for the general populace living near a PWB
facility.
The possible impacts from chemical spills are not addressed due to the pre-defined scope
of this assessment. In addition, environmental releases to surface water were not quantified
because chemical constituents and concentrations in wastewater could not be adequately
characterized for the MHC line alone. This is because PWB manufacturers typically combine
wastewater effluent from the MHC process line with effluent from other PWB manufacturing
processes prior to on-site wastewater pretreatment. The pretreated wastewater is then discharged
to a POTW. Many PWB manufacturers measure copper concentrations in effluent from on-site
pretreatment facilities in accordance with POTW discharge permits, but they do not measure
copper concentrations in MHC line effluent prior to pretreatment. Because there are many
sources of copper-contaminated wastewater in PWB manufacturing, the contribution of the MHC
line to overall copper discharges could not be estimated. Furthermore, most of the MHC
alternatives contain copper, but because these technologies are only now being implemented in
the U.S., their influence on total copper discharges from a PWB facility cannot be determined.
Finally, while data are available on copper discharges from PWB facilities, data are not available
for some of the other metals found in alternatives to electroless copper. Although ecological
hazards are assessed in Section 3.3, without exposure or release data a comparative evaluation of
ecological (aquatic) risk could not be performed.
Inhalation exposure could occur by breathing air containing vapor or aerosol-phase
chemicals from the MHC process line. Inhalation exposures to workers from non-conveyorized
lines are estimated in the exposure assessment. Inhalation exposure to workers from
conveyorized MHC lines is assumed to be negligible because the lines are typically enclosed and
vented to the outside. The model used to estimate daily inhalation exposure is from the EPA
Chemical Engineering Branch Manual for the Preparation of Engineering Assessments (EPA,
1991a):
I = (Cm)(b)(h)
where:
I = daily inhalation potential dose rate (mg/day)
Cm = airborne concentration of substance (mg/m3)
b = inhalation rate (m3/hr)
h = duration (hr/day)
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Daily exposures are then averaged over a lifetime (70 years) for carcinogens, and over the
exposure duration (e.g., 25 years working in a facility) for non-carcinogens,11 using the following
equations:
For carcinogens:
LADD = (I)(EF)(ED)/[(BW)(ATCAR)]
For non-carcinogens:
ADD = (I)(EF)(ED)/[(BW)(ATNC)]
where:
LADD = lifetime average daily dose (mg/kg-day)
ADD = average daily dose (mg/kg-day)
EF = exposure frequency (days/year)
ED = exposure duration (years)
BW = body weight (kg)
ATCAR = averaging time for carcinogenic effects (days)
ATNC = averaging time for non-carcinogenic chronic effects (days)
The daily intake for inhalation exposure to workers was calculated by first modeling
chemical emissions from MHC baths with three air-transport mechanisms: liquid surface
diffusion (desorption), bubble desorption, and aerosol generation and ejection. This chemical
emission rate was combined with data from the Workplace Practices Survey and Performance
Demonstration regarding process room size and air turnover rate to estimate an average indoor
air concentration for the process area. An uncertainty and sensitivity analysis of the air transport
models suggests that the air turnover (ventilation) rate assumption greatly influences the
estimated air concentration in the process area because of its large variability (see the Exposure
Assessment, Section 3.2.3).
Inhalation exposure to a hypothetical population located near a model PWB facility was
estimated using the Industrial Source Complex - Long Term (ISCLT) air dispersion model. The
modeled air concentrations of each contaminant were determined at 100 meters radially from a
PWB facility, and the highest estimated air concentration was used. This model estimates air
concentrations from the process bath emission rates for all processes. These emissions were
assumed to be vented to the ambient environment at the rate emitted from the baths. Inhalation
exposures estimated for the public living 100 meters away from a PWB facility were very low
(approximately 10,000 times lower than occupational exposures).
1' Different averaging times are used for characterizing risk for carcinogenic and non-carcinogenic effects.
For carcinogenic agents, because even a single incidence of exposure is assumed to have the potential to cause
cancer throughout an individual's lifetime, the length of exposure to that agent is averaged over a lifetime. An
additional factor is that the cancer latency period may extend beyond the period of working years before it is
discernible. For chemicals exhibiting non-cancer health effects from chronic (longer-term) exposure, where there is
an exposure threshold (a level below which effects are not expected to occur), only the time period when exposure
is occurring is assumed to be relevant and is used as the averaging time.
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Dermal exposure could occur when skin comes in contact with the bath solution while
dipping boards, adding bath replacement chemicals, etc. Although the survey data suggest that
most MHC line operators do wear gloves, it was assumed in this evaluation that workers do not
wear gloves to account for the fraction that do not. Otherwise, dermal exposure is expected to be
negligible. For dermal exposures, the flux of a material through the skin was estimated based on
EPA, 1992a:
D = (S)(C)(f)(h)(0.001)
where:
D
S
c
f
h
= dermal potential dose rate (mg/day)
= surface area of contact (cm2)
= concentration of chemical in the bath (mg/L)
= flux through skin (cm/hour)
= duration (hours/day)
with a conversion factor of 0.001 (L/cm3)
It should be noted that the above equation was developed for exposures with an infinite
volume of liquid or boundary layer contacting the skin, such as swimming or bathing.
Occupational conditions of dermal contact are likely to be more finite in comparison, resulting in
possible overestimates of flux through the skin.
As for inhalation, daily dermal exposures were then averaged over a lifetime for
carcinogens, and over the exposure duration for non-carcinogens, using the following equations:
For carcinogens:
LADD = (D)(EF)(ED)/[(BW)(ATCAR)]
For non-carcinogens:
ADD = (D)(EF)(ED)/[(BW)(ATNC)]
For dermal exposure, the concentration of chemical in the bath and duration of contact for
workers was obtained from publicly-available bath chemistry data and Workplace Practices
Survey information, respectively. A permeability coefficient (rate of penetration through skin)
was estimated for organics and a default rate assumption was used for inorganics. (Reliance on
such estimates in the absence of data is a source of uncertainty in the exposure assessment.)
Key assumptions in the exposure assessment include the following:
• For dermal exposure, it was assumed that line operators do not wear gloves. Although
the data suggests that most MHC line operators do wear gloves, it was assumed for this
evaluation that workers do not wear gloves to account for the subset of workers who do
not wear proper personal protective equipment.
• For dermal exposure, it was assumed that all non-conveyorized lines are manual hoist.
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• The worker is assumed to have potential dermal contact for the entire time spent hi the
MHC area, divided equally among the baths. This does not mean that a worker has both
hands immersed in a bath for that entire time; but that the skin is in contact with bath
solution (i.e., the hands may remain wet from contact). This assumption may result in an
overestimate of dermal exposure.
• For estimating ambient (outdoor) air concentrations, it was assumed that no air pollution
control technologies are used to remove airborne chemicals from facility air prior to
venting it to the outside.
• For inhalation exposure to workers, it was assumed that chemical emissions to air in the
process room from conveyorized lines are negligible, and that no vapor control devices
(e.g., bath covers) are used on baths in non-conveyorized lines.
• For air concentrations, the model assumes complete mixing in the process room and that
concentrations do not change with time (steady state).
• For all exposures, it was assumed that there is one MHC process line and one line
operator per shift in a process area.
• For characterizing the chemical constituents in the MHC process baths, it was assumed
that the form (speciation) and concentration of all chemicals in the baths are constant over
time, and that MSDSs accurately reflect the concentrations in product lines. If reported
constituent weight percents on an MSDS total less than 100 percent, the remainder is
assumed to be water. These assumptions are discussed further below.
The exposure assessment does not account for any side reactions occurring in the baths
(e.g., the Cannizarro side reaction, which involves the reaction of formaldehyde in electroless
copper baths). A study performed by Merix Corporation found that for every one mole of
formaldehyde reacting in the intended copper deposition process, approximately one mole was
reacting with hydroxide in a Cannizarro side reaction to produce formate ion and methanol
(Williamson, 1996). Other studies have found that the Cannizarro reaction tendency increases
with the alkalinity of the bath. The exposure assessment assumed that the formaldehyde in the
bath is not reacted, and is available to be emitted as formaldehyde. This assumption could tend
to overestimate formaldehyde exposures, and thus risk. However, if side reactions are occurring
with other chemicals that result in the formation of other toxic chemicals (such as methanol), risk
from these chemicals could be underestimated. A search for literature references to studies of
side reactions occurring in PWB baths did not produce sufficient information to quantify the risk
of reaction products in this risk characterization.
Chemical concentrations in baths are based on publicly-available chemistry data,
including MSDS and supplier Product Data Sheets that describe how to mix and maintain
chemical baths. Many MSDSs provided concentration ranges for chemical constituents instead
of absolute concentrations, in which case it was assumed that a chemical is present at the mid-
point of the reported concentration range. This assumption may either overestimate or
underestimate risk for chemicals, depending on their actual concentrations.
Using MSDS data for an exposure assessment can also lead to an underestimate of overall
risk from using a process because the identities of many proprietary ingredients are not included
in the MSDSs. For example, the MSDSs for the organic-palladium alternative list the
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concentrations of some "trade secret" compounds, but do not list any palladium compounds.
Thus, the risk of chemical exposure to the palladium compound in this alternative could not be
evaluated. Efforts were made to obtain this information from suppliers of MHC bath
formulations, and to date, proprietary information has been received from two of the seven
suppliers. Risk information on proprietary chemicals used in non-negligible amounts may be
presented in an attachment to this risk characterization when the remaining proprietary
information has been made available.
Assumptions and parameter values used in these equations and complete results of the
exposure calculations are presented hi the Exposure Assessment (Section 3.2). In order to
provide information about the position an exposure estimate has in the distribution of possible
outcomes, exposure (or risk) descriptors are used following EPA's (EPA, 1992b) Guidelines for
Exposure Assessment. For this risk characterization, the exposure assessment uses whenever
possible a combination of central tendency (either an average or median estimate) and high-end
(90th percentile)12 assumptions, as would be used for an overall high-end exposure estimate. The
90th percentile is used for:
• Hours per day of workplace exposure.
• Exposure frequency (days per year).
• Exposure duration in years (90th percentile for occupational and 95th percentile for
residential exposures).
• The time and frequency of chemical bath and filter replacements, conveyor equipment
cleaning and chemical bath sampling (minutes per occurrence and number of occurrences
per year).
• Estimated workplace air concentrations.
Average values are used for:
• Body weight.
• Concentration of chemical in bath.
• The number of baths in a given process.
Some values used in the exposure calculations, however, are better characterized as "what-if,"
especially pertaining to bath concentrations, use of gloves, and process area ventilation rates for
the model facility. ("What-if represents an exposure estimate based on postulated questions,
making assumptions based on limited data where the distribution is unknown.) Because some
part of the exposure assessment for both inhalation and dermal exposures qualifies as a "what-if
descriptor, the entire assessment should be considered "what-if."
12 For exposure data from the Workplace Practices Survey, this means that 90 percent of the facilities
reported a lower value, and ten percent reported a higher value.
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3.4.2 Summary of Human Health Hazards Assessment
Toxicity data in the form of RfDs, RfCs, NOAELs, LOAELs, and cancer slope (cancer
potency) factors were compiled for inhalation and dermal pathways. CCs and aquatic toxicity
hazard ranks for aquatic species were calculated from aquatic toxicity data on PWB chemicals,
but ecological risk characterization was not carried out because the aquatic exposure could not be
estimated.
Formaldehyde was the only chemical with an established cancer slope (cancer potency)
factor. Other identified or related chemicals in the MHC processes are suspected carcinogens,
but do not have established slope factors. Dimethylformamide and carbon black have been
determined by IARC to possibly be carcinogenic to humans (IARC Group 2B).
Dimethylformamide is used by at least one supplier in the electroless copper process. Carbon
black is used in the carbon and conductive ink processes. Because slope factors (cancer potency
values) are needed for quantitative estimates of cancer risk, cancer risk results are only presented
for formaldehyde.
3.4.3 Methods Used to Calculate Human Health Risks
Estimates of human health risk from chemical exposure are characterized here in terms of
excess lifetime cancer risk, hazard quotient (HQ), and margin of exposure (MOE). This section
defines these risk indicators and discusses the methods for calculating each of them.
Cancer Risk
Cancer risks are expressed as the excess probability of an individual developing cancer
over a lifetime from chemical exposure. For chemicals classified as carcinogens, an upper bound
excess lifetime cancer risk, expressed as a unitless probability, was estimated by the following
equation:
cancer risk = LADDx slope factor (q,*)
where:
Cancer Risk = the excess probability of developing cancer over a lifetime as a result of
exposure to a potential carcinogen. The estimated risks are the upper bound excess
lifetime cancer risks for an individual. (Upper bound refers to the method of determining
a slope factor, where the upper bound value for the slope of the dose-response curve is
used. Excess means the estimated cancer risk is in addition to the already-existing
background risk of an individual contracting cancer from all other causes.)
LADD = the lifetime average daily dose, the estimated potential daily dose rate received
during the exposure duration, averaged over a 70-year lifetime (in mg/kg-day). LADDs
were calculated in the Exposure Assessment (Section 3.2).
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Non-Cancer Risk Indicators
Non-cancer risk estimates are expressed either as a HQ or as a MOE, depending on
whether or not RfDs and RfCs are available. There is generally a higher level of confidence in
the HQ than the MOE, especially if the HQ is based on an RfD or RfC that has been peer-
reviewed by EPA. If an RfD or RfC is available, the HQ is calculated to estimate risk from
chemicals that exhibit chronic, non-cancer toxicity. The HQ is the unitless ratio of the RfD (or
RfC) to the potential dose rate. For MHC chemicals that exhibit non-cancer toxicity, the HQ was
calculated by:
HQ = ADD/RfD
where:
ADD = average daily dose rate, the amount of a chemical ingested, inhaled, or applied
to the skin per unit time, averaged over the exposure duration (in mg/kg-day). ADDs
were calculated in the Exposure Assessment (Section 3.2).
The HQ is based on the assumption that there is a level of exposure (i.e., the RfD or RfC)
below which it is unlikely, even for sensitive subgroups, to experience adverse health effects.
Unlike cancer risk, the HQ does not express probability and is not necessarily linear; that is, an
HQ often does not mean that adverse health effects are ten times more likely to occur than for an
HQ of one. However, the ratio of estimated dose to RfD/RfC reflects level of concern.
For chemicals where an RfD or RfC was not available, a MOE was calculated by:
MOE = NOAEL/ADDorLOAEL/ADD
As with the HQ, the MOE is not a probabilistic statement of risk. The ratio for
calculating MOE is the inverse of the HQ, so that a high HQ (exceeding one) indicates a
potential concern, whereas a high MOE (exceeding 100 for a NOAEL-based MOE or 1,000 for a
LOAEL-based MOE) indicates a low concern level. As the MOE increases, the level of concern
decreases. (As the HQ increases, the level of concern also increases.)
Both the exposure estimates and toxicity data are specific to the route of exposure (i.e.,
inhalation, oral, or dermal). Very few RfDs, NOAELs, or LOAELs were available for dermal
exposure. If oral data were available, the following adjustments were made to calculate dermal
values:
RfDDER = (RfDORAL)(GI absorption)
NOAEL/LOAELDER = (NOAEL or LOAELORAL)(GI absorption)
where:
RfDDER = reference dose adjusted for dermal exposure (mg/kg-day)
NOAEL/LOAELDER = NOAEL or LOAEL adjusted for dermal exposure (mg/kg-day)
GI absorption = gastrointestinal absorption efficiency
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This adjustment is made to account for the fact that the oral RfDs, NOAELs, and LOAELs are
based on an applied dose, while dermal exposure represents an estimated absorbed dose. The
oral RfDs, NOAELs, and LOAELs used to assess dermal risks were therefore adjusted using GI
absorption to reflect an absorbed dose. Table 3.32 lists the GI absorption data used in calculating
risk from dermal exposure.
Table 3.32 Absorption Percentages
Chemicals4
1,3-Benzenediol
2-Ethoxyethanol
Ammonium Chloride
Benzotriazole
3oric Acid
Copper (I) Chloride
Oiethylene Glycol Ethyl Ether
Diethylene Glycol Methyl Ether
Diethylene Glycol n-Butyl Ether
Oimethylformamide
Ethanolamine
Ethylene Glycol
Fluoroboric Acid
Formaldehyde
Hydrogen Peroxide
Hydroxyacetic Acid
[sopropyl Alcohol, 2-Propanol
Methanol
Palladium
Palladium Chloride
Phenol
Potassium Cyanide
Silver
Sodium Chlorite
Sodium Cyanide
Sodium Sulfate
Stannous Chloride
Vanillin
G.I. Tract Absorption (%)
100
100
97
20
90
60
20
20
20
20
20
100
100
1
5
20
20
100
5
5
20
5
21
5
5
100
3
6
Source of Data
NTP, 1992
assumption6
Reynolds, 1982
assumption15
EPA, 1990
EPA, 1994a
assumption*
assumption1"
assumption11
assumption11
assumption1"
ATSDR, 1993
Stokinger, 1981
EPA, 1995c
default (EPA, 1989)
assumption1"
assumption1"
Lington & Bevan, 1994
Beliles, 1994
Beliles, 1994
assumption11
default (EPA, 1989)
ATSDR, 1990b
default (EPA, 1989)
default (EPA, 1989)
HSDB, 1995
ATSDR, 1992
Kirwin and Galvin, 1993
Includes only those chemicals where dermal HQs or MOEs were calculated.
b An assumption of 20 percent was made for organic chemicals when no other data were available.
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3.4.4 Results of Calculating Risk Indicators
This section presents the results of calculating risk indicators for both the occupational
setting and the ambient (outdoor) environment. When considering these risk characterization
results, it should be remembered that the results are intended for use in relative risk comparisons
between processes based on a model PWB facility, and should not be used as absolute indicators
for potential health risks to MHC line workers or to the public.
Occupational Setting
Estimated cancer risks and non-cancer risk indicators from occupational exposure to
MHC chemicals are presented below. It should be noted that no epidemiological studies of
health effects among PWB workers were located.
Cancer Risk. The electroless copper process is the only process containing a chemical
for which a cancer slope (cancer potency) factor is available. Therefore, it is the only process for
which a cancer risk has been estimated. Formaldehyde has an EPA weight-of-evidence
classification of Group Bl, a Probable Human Carcinogen. The EPA Group Bl classification is
typically based on limited evidence of carcinogenicity in humans, sufficient evidence of
carcinogenicity in animals, and additional supporting evidence. The cancer slope factor for
formaldehyde is based exclusively on animal data, and is associated with nasal cancer.
Inhalation exposure estimates are based on the assumptions that emissions to indoor air
from conveyorized lines are negligible, that the air in the process room is completely mixed and
chemical concentrations are constant over time, and that no vapor control devices (e.g., bath
covers) are used in non-conveyorized lines. The exposure estimates use 90th percentile modeled
air concentrations (0.54 mg/m3 for formaldehyde in the non-conveyorized electroless copper
process), which means that, based on the Workplace Practices Survey data and publicly-available
information on bath concentrations, approximately 90 percent of the facilities are expected to
have lower air concentrations and, therefore, lower risks. Using 90th percentile data is consistent
with EPA policy for estimating upper-bound exposures.
With regard to formaldehyde cancer risk, EPA in 1987 issued a risk assessment in which
formaldehyde was classified as a Group Bl Probable Human Carcinogen; in addition it was
determined to be an irritant to the eyes and respiratory tract. A quantitative risk assessment for
cancer was presented using available exposure data and a cancer slope (cancer potency) factor of
0.046 per milligram formaldehyde per kilogram body weight per day. In 1991, EPA proposed a
modification of this assessment using additional animal testing and exposure data that had
become available. This modification would result in a 50-fold reduction in estimated cancer risk
following inhalation exposure to formaldehyde. However, EPA's Science Advisory Board
recommended that formaldehyde cancer risk be presented as a range of risk estimates using data
from both the 1987 and 1991 assessments, due to the many uncertainties and data gaps that
preclude the use of one assessment to the exclusion of the other. Therefore, upper bound
maximum individual cancer risk over a lifetime is presented as a range from lx 10"3 (1 in 1,000)
to 2 x 10'5 (1 hi 50,000) based on a workplace concentration of 0.54 milligrams formaldehyde per
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cubic meter of air (over an 8 hour-day) for line operators using the non-conveyorized electroless
copper process. It should be pointed out that intensity of exposures to formaldehyde (air
concentration) may be more important than average exposure levels over an 8-hour day in
increasing cancer risk (Hernandez et al., 1994). The use of modeled, steady state, workplace air
concentrations instead of actual monitoring data of average and peak concentrations thus
emerges as a significant source of uncertainty in estimating cancer risk to workers exposed to
formaldehyde in this industry. The available toxicological data do not indicate that dermal
exposure to formaldehyde increases cancer risk, but no dermal cancer studies were located.
To provide further information on the possible variation in occupational formaldehyde
exposure and risk estimates, formaldehyde cancer risk is also estimated using average and
median values, as would be done for a central tendency exposure estimate.13 The following
median or average parameter values are used:
• The 50th percentile air concentration estimated from the quantitative uncertainty analysis
(Section 3.2.3) of 0.14 mg/m3 (compared to the high-end point estimate of 0.54 mg/m3).
• The median job tenure for men in the U.S. of 4.0 years (Bureau of Labor Statistics, 1997)
(compared to the 95th percentile of 25 years).
• The average value of 6.8 hrs/day for a line operator from the Workplace Practices Survey
(compared to the 90th percentile of 8 hrs/day).
• The average exposure frequency of 250 days/year from the Workplace Practices Survey
(compared to the 90th percentile of 306 days/year).
Using these values, there is approximately a 35-fold reduction in estimated exposure with the
estimated "central tendency" LADD of 8.0 x 10'4 mg/kg-day. Combined with the slope factor of
0.046 per mg/kg-day, this results in a range of cancer risk of 3 x 10'5 (1 in 33,000) to 6 x 10'7 (1
in 1.7 million) considering the 50-fold reduction.
Risks to other workers were assumed to be proportional to the amount of time spent in
the process area. Based on the Workplace Practices Survey data, the average line operator
spends 1,900 hours per year in the MHC process area. Annual average exposure times (i.e., time
spent in the process area) for various worker types from the Workplace Practices Survey database
are listed below. The number in parenthesis is the ratio of average time for that worker type to
the average time for a line operator.
• Contract worker: 62 hours per year (0.033).
• Laboratory technician: 1,100 hours per year (0.5 8).
• Maintenance worker: 930 hours per year (0.49).
• Supervisor: 1,150 hours per year (0.61).
• Wastewater treatment operator: 1,140 hours per year (0.60).
• Other: 1,030 hours per year (0.54).
13 This "central tendency" estimate should also be considered a "what-if' exposure estimate, because of
the uncertainty of the process area ventilation rate data.
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Slope factors (cancer potency values) are needed to calculate estimates of cancer risk.
Because formaldehyde was the only identified chemical with an established slope factor, cancer
risk results are only presented here for formaldehyde. The only chemicals other than
formaldehyde classified as probably human carcinogens (IARC Group 2B) are
dimethylformamide and carbon black. Like formaldehyde, the evidence for carcinogenic effects
is based on animal data. However, unlike formaldehyde, slope factors are not available for either
chemical. There are potential cancer risks to workers from both chemicals, but they cannot be
quantified. Dimethylformamide is used in the electroless copper process. Workplace exposures
have been estimated but cancer potency and cancer risk are unknown. Carbon black is used in
the carbon and conductive ink processes. Occupational exposure due to air emissions from the
carbon baths is expected to be negligible because the carbon process is typically conveyorized
and enclosed. There may be some airborne carbon black, however, from the drying oven steps,
which was not quantified in the exposure assessment. Carbon black is also used in one product
line of the conductive ink process; exposures from conductive ink were not characterized.
Non-Cancer Risk. HQs and MOEs for line operators and laboratory technicians from
workplace exposures are presented in Appendix E. An HQ exceeding one indicates a potential
concern. Unlike cancer risk, HQ does not express probability, only the ratio of the estimated
dose to the RfD or RfC, and it is not necessarily linear (an HQ often does not mean that adverse
health effects are ten times more likely than an HQ of one).
EPA considers high MOE values, such as values greater than 100 for a NOAEL-based
MOE or 1,000 for a LOAEL-based MOE, to pose a low level of concern (Barnes and Dourson,
1988). As the MOE decreases, the level of concern increases. Chemicals are noted here to be of
potential concern if a NOAEL-based MOE is lower than 100, a LOAEL-based MOE is lower
than 1,000, or a MOE based on an effect level that was not specified as a LOAEL is less than
1,000. As with HQ, it is important to remember that the MOE is not a probabilistic statement of
risk.
Inhalation risk indicators of concern are presented in Table 3.33. Inhalation exposure
estimates are based on the assumptions that emissions to air from conveyorized lines are
negligible, that the air in the process room is completely mixed and chemical concentrations are
constant over time, and that no vapor control devices (e.g., bath covers) are used in non-
conveyorized lines.
For inhalation exposure, 2-ethoxyethanol is the only MHC chemical with an HQ greater
than one; this is for a line operator in the non-conveyorized electroless copper process.
Chemicals with MOEs below the above-mentioned levels for inhalation exposure include the
following:
• For non-conveyorized electroless copper: copper (I) chloride, ethanolamine, ethylene
glycol, formaldehyde, methanol, and sulfuric acid for a line operator.
• For non-conveyorized tin-palladium: ethanolamine and sulfuric acid for a line operator.
• For non-conveyorized non-formaldehyde electroless copper: sulfuric acid for a line
operator.
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3.4 RISK CHARACTERIZATION
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3.4 RISK CHARACTERIZATION
Dermal risk indicators of concern are presented in Table 3.34. Dermal exposure
estimates are based on the assumption that workers do not wear gloves and that all non-
conveyorized lines are operated by manual hoist. Chemicals with HQs from dermal exposure
greater than one include:
• Formaldehyde for a line operator in the non-conveyorized electroless copper and
conveyorized electroless copper processes.
• Stannous chloride for a line operator in the non-conveyorized electroless copper,
conveyorized electroless copper, non-formaldehyde electroless copper (non-
conveyorized), non-conveyorized tin-palladium, and conveyorized tin-palladium
processes.
Chemicals with NOAEL-based MOEs lower than 100, or LOAEL-based MOEs or other MOEs
lower than 1,000 for dermal exposure include the following:
• For non-conveyorized electroless copper: copper (I) chloride, fluoroboric acid,
palladium, and sodium chlorite for a line operator; copper (I) chloride, fluoroboric acid,
and palladium for a laboratory technician.
• For conveyorized electroless copper: copper (I) chloride, fluoroboric acid, palladium,
and sodium chlorite for a line operator; copper (I) chloride, fluoroboric acid, and
palladium for a laboratory technician.
• For non-conveyorized non-formaldehyde electroless copper: sodium chlorite for a line
operator.
• For non-conveyorized tin-palladium: copper (I) chloride, fluoroboric acid, palladium and
palladium chloride for a line operator and laboratory technician.
• For conveyorized tin-palladium: copper (I) chloride, fluoroboric acid, palladium and
palladium chloride for a line operator and laboratory technician.
It should be noted that Tables 3.33 and 3.34 do not include chemicals for which toxicity
data were unavailable.
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Ambient (Outdoor! Environment
Cancer Risk. As with the occupational setting, the electroless copper process is the only
process for which a cancer risk to humans in the ambient (outdoor) environment has been
estimated. These results are for both conveyorized and non-conveyorized electroless copper
processes, assuming that emissions from both process configurations are vented to the outside.
Tfie upper bound excess14 individual lifetime cancer risk for nearby residents from the non-
conveyorized electroless copper process from formaldehyde inhalation was estimated to range
from 2 x 10'9 to 1 x 10'7. The risk for nearby residents from the conveyorized electroless copper
process was estimated to range from 6 x 10'9 to 3 x 10'7. Again, the higher values (3 x 10"7 for
conveyorized and 1 x 10-7 for non-conveyorized) are based on a LADDs of 7.0 x 10'6 mg/kg-day
and 2.6 x 10'6 mg/kg-day, respectively, and a slope (cancer potency) factor of 0.046 per mg/kg-
day. The lower values (6 x 10'9 for conveyorized and 2 x 10'9 for non-conveyorized) take into
account a possible 50-fold reduction in inhalation unit risk.
The discussion of reduction in estimated cancer risk from Section 3.4.1 applies to these
results as well. Formaldehyde has been classified as Group Bl, a Probable Human Carcinogen
based on limited evidence of carcinogenicity in humans, sufficient evidence of carcinogenicity in
animals, and additional supportive evidence. These estimates indicate low concern and are
interpreted to mean that, over a lifetime, an individual resident is expected to have no more than
one excess chance in ten million of developing cancer from exposure to formaldehyde from a
nearby facility using the non-conveyorized electroless copper process, or one excess chance in
three million of developing cancer from exposure to formaldehyde from the conveyorized
electroless copper process. The conveyorized electroless copper risk is slightly higher due to the
larger surface areas of conveyorized baths, resulting in higher modeled air emission rates.
None of the other process alternatives use chemicals for which cancer slope factors were
available, so no other cancer risks were estimated. Other identified chemicals in the MHC
processes are suspected carcinogens, but do not have established slope factors.
Dimethylformamide and carbon black have been determined by IARC to possibly be
carcinogenic to humans (IARC Group 2B). Dimethylformamide is used in the electroless copper
process. Carbon black is used in the carbon and conductive ink processes. Carbon black is not
expected to be released to outside air in any significant amount from a facility using the carbon
process. This is because carbon black is not a volatile compound, and aerosol releases are not
expected because it is not used in an air-sparged bath, Conductive ink exposures and risks were
not characterized.
Non-Cancer Risk. Appendix E presents HQs for estimated chemical releases to ambient
air, and subsequent inhalation by residents near a model facility. Chemicals below^he emission
rate cutoff of 23 kg/year are not included because below this emission rate exposures are
Upper bound refers to the method of determining a slope factor, where the upper bound value
(generated from a certain probability statement) for the slope of the dose-response curve is used. Excess means the
estimated cancer risk is in addition to the already-existing background risk of an individual contracting cancer from
all other causes.
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expected to be negligible. All HQs are less than one for ambient exposure to the general
population, indicating low concern.
These results suggest there is low risk to nearby residents, based on incomplete but best
available data. Data limitations include the use of modeled air concentrations using average data
rather than site-specific, measured concentrations. For estimating ambient (outdoor) air
concentrations, one key assumption is that no air pollution control technologies are used to
remove airborne chemicals from facility air prior to venting it to the outside. Other data
limitations are the lack of waterborne and solid waste data to characterize exposure routes in
addition to inhalation, and lack of toxicity data for many chemicals.
Appendix E presents MOEs from ambient air exposures. The chemicals included are
those above the emission rate cutoff and for which NOAEL or LOAEL data were available.
(Also if an HQ could be calculated an MOE was not.) All MOEs for ambient exposure are
greater than 1,000 for all processes, indicating low concern from the estimated air concentrations.
3.4.5 Uncertainties
An important component of any risk characterization is the identification and discussion
of uncertainties. There are uncertainties involved in the measurement and selection of hazard
data, and in the data, models and scenarios used in the Exposure Assessment. Any use of the risk
characterization should include consideration of these uncertainties.
Uncertainties in the hazard data (typically encountered in a hazard assessment) include
the following:
• Using dose-response data from high dose studies to predict effects that may occur at low
levels.
• Using data from short-term studies to predict the effects of long-term exposures.
• Using dose-response data from laboratory animals to predict effects in humans.
• Using data from homogeneous populations of laboratory animals or healthy human
populations to predict the effects on the general human population, with a wide range of
sensitivities. (This uncertainty is due to natural variations in human populations.)
• Using LOAELs and NOAELs in the absence of peer-reviewed RfDs and RfCs.
• Possible increased or decreased toxicity resulting from chemical interactions.
• Assuming a linear dose-response relationship for cancer risk (in this case for
formaldehyde).
• Effects of chemical mixtures not included in toxicity testing (effects may be independent,
additive, synergistic, or antagonistic).
• Possible effects of substances not evaluated because of a lack of chronic/subchronic
toxicity data.
Another source of uncertainty comes from use of structure-activity relationships (SARs)
for estimating human health hazards in the absence of experimental toxieity data. Specifically,
this was done for: dimethylaminoborane, EDTA (sodium salt), fluoroboric acid, graphite,
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magnesium carbonate, m-nitrobenzene sulfonic acid, monopotassium peroxymonosulfate,
palladium chloride, phosphoric acid, potassium bisulfate, potassium carbonate, potassium
persulfate, potassium sulfate, p-toluene sulfonic acid, sodium bisulfate, sodium hypophosphite,
and sodium persulfate.
Uncertainties in assessing risk from dermal exposure come from the use of toxicological
potency factors from studies with a different route of exposure than the one under evaluation
(i.e., using oral toxicity measures to estimate dermal risk). This was done for nine chemicals
with oral RfDs and 15 chemicals with oral NOAELs (as noted in Tables 3.25 and 3.26).
Uncertainties in dermal risk estimates also stem from the use of default values for missing
gastrointestinal absorption data. Specifically, this was done for benzotriazole, diethylene glycol
ethyl ether, diethylene glycol n-butyl ether, ethanolamine, 2-ethoxyethanol, hydrogen peroxide,
hydroxyacetic acid, isopropyl alcohol, potassium cyanide, sodium chlorite, and sodium cyanide.
Uncertainties in the Exposure Assessment include the following:
• Accuracy of the description of exposure setting: how well the model facility used in the
assessment characterizes an actual facility; the likelihood of exposure pathways actually
occurring (scenario uncertainty).
• Missing data and limitations of workplace survey data: this includes possible effects of
any chemicals that may not have been included (e.g., minor ingredients in the
formulations, proprietary chemical identities not disclosed by suppliers); possible effects
of side reactions in the baths which were not considered; and survey data with limited
facility responses.
• Estimating exposure levels from averaged data and modeling in the absence of measured,
site-specific data.
• Data limitations in the Source Release Assessment: releases to surface water and land
could not be characterized quantitatively.
• Chemical fate and transport model applicability and assumptions: how well the models
and assumptions represent the situation being assessed and the extent to which the models
have been validated or verified (model uncertainty).
• Parameter value uncertainty, including measurement error, sampling (or survey) error,
parameter variability, and professional judgement.
Key assumptions made in the Exposure Assessment are discussed in Section 3.4.1.
3.4.6 Conclusions
This risk characterization uses a health-hazard based framework and a model facility
approach to compare the health risks of one MHC process technology to the risks associated
which switching to an alternative technology. As much as possible, reasonable and consistent
assumptions are used across alternatives. Data to characterize the model facility and exposure
patterns for each process alternative were aggregated from a number of sources, including PWB
shops in the U.S. and abroad, supplier data, and input from PWB manufacturers at project
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meetings. Thus, the model facility is not entirely representative of any one facility, and actual
risk could vary substantially, depending on site-specific operating conditions and other factors.
When using the results of this risk characterization to compare health effects among
alternatives, it is important to remember that this is a screening level rather than a comprehensive
risk characterization, both because of the predefined scope of the assessment and because of
exposure and hazard data limitations. It should also be noted that this approach does not result in
any absolute estimates or measurements of risk, and even for comparative purposes, there are
several important uncertainties associated with this assessment.
Primary among these uncertainties is the incomplete identification of all chemicals
among the process alternatives because of trade secret considerations. This factor alone
precludes any definitive recommendations among the processes because the health risks from all
relevant chemicals could not be evaluated. It should be noted here also that chemical suppliers to
the PWB industry are in the sole position to fill these data gaps for a more complete
assessment.15 Without that, conclusions can only be drawn based on the best available
information. It should also be noted that chemical suppliers are required to report on an MSDS
(under 29 CFR Part 1910.1200) that a product contains hazardous chemicals, if present at one
percent or greater of a product composition, or 0.1 percent or greater for carcinogens. The
chemical manufacturer may withhold the specific chemical identity from the MSDS, provided
that the MSDS discloses the properties and effects of the hazardous chemical. A review of the
available MSDSs indicates that there are hazardous chemicals listed as trade secret ingredients:
three in electroless copper, one in graphite, three in organic-palladium, and one in tin-palladium.
Section 2.1.4 presents these results and discusses the use of MSDS information further.
Another significant source of uncertainty is the limited data available for dermal toxicity
and the use of oral to dermal extrapolation when dermal toxicity data were unavailable. There is
high uncertainty in using oral data for dermal exposure and in estimating dermal absorption rates,
which could result in either over- or under-estimates of exposure and risk.
A third significant source of uncertainty is from the use of structure-activity relationships
to estimate toxicity in the absence of measured toxicity data, and the lack of peer-reviewed
toxicity data for many MHC chemicals. Other uncertainties associated with the toxicity data
include the possible effects of chemical interactions on health risks, and extrapolation of animal
data to estimate human health risks from exposure to formaldehyde and other PWB chemicals.
Electrochemicals, LeaRonal, and Solution Technology Systems have provided information on
proprietary chemical ingredients to the project. W.R. Grace had been preparing to transfer information on
proprietary chemical ingredients in the conductive ink technology when it was determined that this information was
no longer necessary because risk from the conductive ink technology could not be characterized. The other
suppliers participating in the project (Atotech, Enthone-OMI, MacDermid, and Shipley have declined to provide
proprietary information on their MHC technologies. The absence of information on proprietary chemical
ingredients is a significant source of uncertainty in the risk characterization. Risk information for proprietary
ingredients, as available, will be presented in the final CTSA, but chemical identities, concentrations, and chemical
properties will not be listed.
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Another major source of uncertainty in estimating exposure is the reliance on modeled
data (i.e., modeled air concentrations) to estimate worker exposure. It should also be noted that
there is no comparative evaluation of the severity of effects for which HQs and MOEs are
reported.
The Exposure Assessment for this risk characterization used, whenever possible, a
combination of central tendency and high-end assumptions, as would be used for an overall high-
end exposure estimate. Some values used in the exposure calculations, however, are better
characterized as "what-if," especially pertaining to bath concentrations, use of gloves, and
process area ventilation rates for a model facility. Because some part of the exposure assessment
for both inhalation and dermal exposures qualifies as a "what-if descriptor, the entire
assessment should be considered "what-if."
Among those health risks evaluated, it can be concluded that alternatives to the non-
conveyorized electroless copper process appear to present a lower overall risk, due to reduced
cancer risk to PWB workers when the use of formaldehyde is eliminated. Other adverse effects
from chronic, low level exposures to chemicals in the alternative processes provide some basis
for additional comparison. While alternatives to electroless copper appear to pose less overall
risk, there is insufficient information to compare these alternatives among themselves to
determine which of the alternatives pose the least risk.
Occupational Exposures and Risks
Health risk to workers are estimated for inhalation exposure to vapors and aerosols from
MHC baths and for dermal exposure to MHC bath chemicals. Inhalation exposure estimates are
based on the assumptions that emissions to indoor air from conveyorized lines are negligible, that
the air in the process room is completely mixed and chemical concentrations are constant over
time, and that no vapor control devices (e.g., bath covers) are used in non-conveyorized lines.
Dermal exposure estimates are based on the assumption that workers do not wear gloves and that
all non-conveyorized lines are operated by manual hoist. Dermal exposure to line operators on
non-conveyorized lines is estimated for routine line operation and maintenance (e.g., bath
replacement, filter replacement, etc.), and on conveyorized lines for bath maintenance activities
alone.
Risk results indicate that alternatives to the non-conveyorized electroless copper process
pose lower occupational risks. However, there are occupational inhalation risk concerns for
some chemicals in the electroless copper, non-formaldehyde electroless copper, and tin-
palladium non-conveyorized processes. In addition, there are occupational risk concerns for
dermal contact with some chemicals in the electroless copper, non-formaldehyde electroless
copper, and tin-palladium processes for either conveyorized or non-conveyorized equipment.
Cancer Risk. The non-conveyorized electroless copper process is the only process for
which an occupational cancer risk has been estimated (for formaldehyde). Formaldehyde has
been classified by EPA as Group Bl, a Probable Human Carcinogen. The upper bound excess
individual cancer risk estimate for line operators in the non-conveyorized electroless copper
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process from formaldehyde inhalation may be as high as one in a thousand, but may be 50 times
less, or one in 50,000.16 Risks to other workers were assumed to be proportional to the amount
of tune spent in the process area, which ranged from three to 61 percent of the risk for a line
operator.
Other identified chemicals in the MHC processes are suspected carcinogens.
Dimethylformamide and carbon black have been determined by IARC to possibly be
carcinogenic to humans (IARC Group 2B). Dimethylformamide is used in the electroless copper
process and carbon black is used in the carbon and conductive ink processes. There are potential
cancer risks to workers from both chemicals, but because there are no slope factors, the risks
cannot be quantified.
Non-Cancer Risk. For non-cancer risk, HQs greater than one were estimated for
occupational exposures to chemicals in the non-conveyorized and conveyorized electroless
copper processes; the non-conveyorized and conveyorized tin-palladium processes, and the non-
conveyorized non-formaldehyde electroless process. Also, several chemicals result in estimated
MOEs lower than 100 or LOAEL-based MOEs lower than 1,000 for occupational exposures in
the non-conveyorized and conveyorized electroless copper processes, non-conveyorized and
conveyorized tin-palladium processes, and non-conveyorized non-formaldehyde electroless
copper process.
Based on calculated occupational exposure levels, there may be adverse health effects to
workers exposed to these chemicals with a HQ exceeding 1.0 or an MOE less than 100 or 1,000.
However, it should be emphasized that these conclusions are based on screening level estimates.
These numbers are used here for relative risk comparisons between processes, and should not be
used as absolute indicators for potential health risks to MHC line workers.
Ambient (Outdoor) Exposures and Risks
Public health risk was estimated for inhalation exposure for the general populace living
near a facility. Public exposure estimates are based on the assumption that emissions from both
conveyorized and non-conveyorized process configurations are vented to the outside. The risk
indicators for ambient exposures to humans, although limited to airborne releases, indicate low
concern for nearby residents. The upper bound excess individual cancer risk for nearby residents
from formaldehyde in the non-conveyorized electroless copper process was estimated to be from
approaching zero to 1 x 10"7 (one in ten million) and from approaching zero to 3 x 10'7 (one in
three million) for the conveyorized electroless copper process. Formaldehyde has been classified
by EPA as Group Bl, a Probable Human Carcinogen. All hazard quotients are less than one for
ambient exposure to the general population, and all MOEs for ambient exposure are greater than
To provide further information on the possible variation of formaldehyde exposure and risk, an
additional exposure estimate is provided using average and median values (rather than high-end) as would be done
for a central tendency exposure estimate. This results in approximately a 35-fold reduction in occupational
formaldehyde exposure and risk.
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3.4 RISK CHARACTERIZATION
1,000 for all processes, indicating low concern from the estimated air concentrations for chronic
non-cancer effects.
Ecological Hazards
The CIS A methodology typically evaluates ecological risk in terms of risks to aquatic
organisms in streams that receive treated or untreated effluent from manufacturing processes.
Stream concentrations were not available, however, and could not be estimated because of data
limitations (i.e., insufficient characterization of constituents and their concentrations in facility
wastewater). Because exposure (i.e., stream concentrations) could not be quantified ecological
(aquatic) risk is not characterized. Instead, an ecological hazards assessment was performed
(Section 3.3.3), based only on chemical toxicity to aquatic organisms. The results of this
evaluation are summarized briefly here.
CCs were estimated for MHC chemicals using an established EPA method. A CC is an
acute or chronic toxicity value divided by an assessment factor (AsF). AsFs are dependent on
the amount and type of toxicity data contained in a toxicity profile and reflect the amount of
uncertainty about the potential effects associated with a toxicity value. CCs were determined for
aquatic species (e.g., Daphnia, algae, and/or fish). The lowest CC is for copper sulfate, based on
fish toxicity data.
Chemicals are also ranked for aquatic toxicity concern levels using established EPA
criteria (high, moderate, and low concern) based on the available toxicity data. The number of
chemicals with a high aquatic hazard concern level include nine in the electroless copper process,
two in carbon, two in conductive ink, none in conductive polymer, two in graphite, three in non-
formaldehyde electroless copper, one in organic-palladium, and seven in the tin-palladium
process.
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3.5 PROCESS SAFETY ASSESSMENT
3.5 PROCESS SAFETY ASSESSMENT
Process safety is the concern of employers and employees alike. Each company has the
obligation to provide its employees with a safe and healthy work environment, while each
employee is responsible for his/her own safe personal work habits. An effective process safety
program identifies potential workplace hazards and, if possible, seeks to eliminate or at least
reduce their potential for harm. In the MHC process of PWB manufacturing, these hazards may
be either chemical hazards or process hazards. Chemicals used in the MHC process can be
hazardous to worker health and therefore must be handled and stored properly, using appropriate
personal protective equipment and safe operating practices. Automated equipment can be
hazardous to employees if safe procedures for cleaning, maintaining, and operating are not
established and regularly performed. These hazards can result in serious injury and health
problems to employees, and potential damage to equipment.
The U.S. Department of Labor and the Occupational Safety and Health Administration
(OSHA) have established safety standards and regulations to assist employers in creating a safe
working environment and protect workers from potential workplace hazards. In addition,
individual states may also have safety standards regulating chemical and physical workplace
hazards for many industries. Federal safety standards and regulations affecting the PWB
industry can be found in the Code of Federal Regulation (CFR) Title 29, Part 1910 and are
available by contacting your local OSHA field office. State and local regulations are available
from the appropriate state office. This section of the CTSA presents chemical and process safety
concerns associated with the MHC baseline and substitutes, as well as OSHA requirements to
mitigate these concerns.
3.5.1 Chemical Safety Concerns
As part of its mission, OSHA's Hazard Communication Standard (29 CFR 1910.1200)
requires that chemical containers be labeled properly with chemical name and warning
information [.1200(1)], that employees be trained in chemical handling and safety procedures
[.1200(h)J, and that a MSDS be created and made available to employees for every chemical or
formulation used in the workplace [. 1200(g)]. Each MSDS must be in English and include
information regarding the specific chemical identity of the hazardous chemical(s) involved and
the common names. In addition, information must be provided on the physical and chemical
characteristics of the hazardous chemical; known acute and chronic health effects and related
health information; exposure limits; whether the chemical is a carcinogen; emergency and first-
aid procedures; and the identification of the organization preparing the data sheet. Copies of
MSDSs for all of the chemicals used must be kept and made available to workers who may come
into contact with the process chemicals during their regular work shift.
In order to evaluate the chemical safety concerns of the various MHC processes, MSDSs
for 172 chemical products comprising eight MHC technology categories were collected and
reviewed for potential hazards to worker safety. The results of that review are summarized and
discussed in the categories below. General information on OSHA storage and handling
requirements for chemicals in these hazard categories are located in the process safety section of
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3.5 PROCESS SAFETY ASSESSMENT
this chapter. For a more detailed description of OSHA storage and handling requirements for
MHC chemical products in these categories contact your area OSHA field office or state
technical assistance program for assistance.
Flammable. Combustible, and Explosive MHC Chemical Products
A breakdown of MHC chemical products that when in concentrated form are flammable,
combustible, explosive, or pose a fire hazard is presented in Table 3.35. The following lists
OSHA definitions for chemicals hi these categories, and discusses the data presented in the
table.
Flammable - A flammable chemical is defined by OSHA [29 CFR 1910.1200(c)] as one of the
following:
• An aerosol that, when tested by the method described in 16 CFR 1500.45, yields a flame
projection exceeding 18 inches at full valve opening, or a flashback at any degree of
valve opening.
• A gas that has: 1) at ambient temperature and pressure, forms a flammable mixture with
air at a concentration of 13 percent by volume or less; or 2) when it, at ambient
temperature and pressure, forms a range of flammable mixtures with air wider than 12
percent by volume, regardless of the lower limit.
• A liquid that has a flashpoint below 100° F (37.8° C), except any mixture having
components with flashpoints of 100° F (37.8° C) or higher, the total of which make up 99
percent or more of the total volume of the mixture.
• A solid, other than a blasting agent or explosive as defined in 29 CFR 1910.109(a), that is
liable to cause fire through friction, absorption of moisture, spontaneous chemical
change, or retained heat from manufacturing or processing, or which can be ignited
readily and when ignited burns so vigorously and persistently as to create a serious
hazard.
Twenty chemical products are reported as flammable according to MSDS data. While all
of the products have flashpoints near or below 100° F, several of the products reported as
flammable have flashpoints greater than 200° F with one as high as 400° F. Although several
chemical products are flammable in their concentrated form, most chemical baths in the MHC
process line contain non-flammable aqueous solutions.
Combustible Liquid - As defined by OSHA [29 CFR 1910.1200(c)]5 a liquid that is considered
combustible has a flashpoint at or above 100° F (37.8° C), but below 200° F (93.3° C), except
any mixture having components with flashpoints of 200° F (93.3° C), or higher, the total volume
of which make up 99 percent or more of the total volume of the mixture. Two chemical products
have been reported as combustible by their MSDSs, both with flashpoints above 155° F.
Explosive - As defined by OSHA [29 CFR 1910.1200(c)], a chemical is considered explosive if
it causes a sudden, almost instantaneous release of pressure, gas, and heat when subjected to
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3.5 PROCESS SAFETY ASSESSMENT
sudden shock, pressure, or high temperature. Seven chemical products are reported as explosive
by their MSDSs.
Fire Hazard - A chemical product that is a potential fire hazard is required by OSHA to be
reported on the product's MSDS. According to MSDS data, three chemical products are reported
as potential fire hazards.
Table 3.35 Flammable, Combustible, Explosive, and Fire Hazard Possibilities
for MHC Processes
MHC Process
Carbon
Conductive Ink
Conductive Polymer
Electroless Copper
Graphite
Non-Formaldehyde
Electroless Copper
Palladium
Bath Type
Cleaner
Conditioner
Other (Anti-Tarnish)
Print Ink
Polymer
Accelerator
Anti-Tarnish
Cleaner/Conditioner
Electroless Copper
Microetch
Microetch
Accelerator
Anti-Tarnish
Microetch
Accelerator
Cleaner/Conditioner
Other (Anti-Tarnish)
Hazardous Property*
Flammable
2(2)
3(3)
2(2)
1(3)
1(5)
2(4)
1(8) .
2(25)
1(9)
1(2)
1(1)
1(4)
1(6)
1(3)
Combustible
1(25)
1(6)
Explosive
5(5)
1(8)
1(10)
Fire Hazard
1(25)
1(4)
1(10)
Table entries are made in the following format - # of products meeting OSHA definition for the given hazardous
properly as reported in the products MSDSs (Total # of products in the process bath). A blank entry means that
none of the products for the specific process bath meet the OSHA reporting criteria for the given property.
Example: For the palladium process accelerator bath, 1 (10) means that one of the ten products in the bath were
classified as explosive per OSHA criteria as reported on the products MSDSs.
3.5.2 Corrosive, Oxidizer, and Reactive MHC Chemical Products
A breakdown of MHC chemical baths containing chemical products that are corrosive,
oxidizers, or reactive in their concentrated form is presented in Table 3.36. The table also lists
process baths that contain chemical products that may cause a sudden release of pressure when
opened. The following lists OSHA definitions for chemicals in these categories and discusses
the data presented in the table.
Corrosive - As defined by OSHA (29 CFR 1910.1200 [Appendix A]), a chemical is considered
corrosive if it causes visible destruction of, or irreversible alterations in, living tissue by chemical
action at the site of contact, as determined by the test method described by the U.S. Department
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of Transportation 49 CFR Part 173 Appendix A. This term does not apply to chemical action on
inanimate surfaces. A review of MSDS data found that 59 MHC chemical products are reported
as corrosive in their concentrated form. Some MHC baths may also be corrosive, but MSDSs do
not provide data for the process chemical baths once they are prepared.
Oxidizer - As defined by OSHA (29 CFR 1910.1200[c]), an oxidizer is a chemical other than a
blasting agent or explosive as defined by OSHA [29 CFR 1910.109(a)], that initiates or promotes
combustion in other materials, thereby causing fire either of itself or through the release of
oxygen or other gases. Twelve chemical products are reported as oxidizers according to MSDS
data.
Reactive - A chemical is considered reactive if it is readily susceptible to change and the possible
release of energy. EPA gives a more precise definition of reactivity for solid wastes. As defined
by EPA (40 CFR 261.23), a solid waste is considered reactive if it exhibits any of the following
properties: 1) is normally unstable and readily undergoes violent change without detonating; 2)
reacts violently or forms potentially explosive mixtures with water; 3) when mixed with water,
generates toxic gases, vapors, or fumes in a quantity that can present a danger to human health or
the environment (for a cyanide or sulfide bearing waste, this includes when exposed to a pH
between 2 and 12.5); 4) is capable of detonation or explosive reaction if subjected to a strong
initiated source or if heated under confinement; or 5) is readily capable of detonation or
explosive decomposition or reaction at standard temperature and pressure. A review of MSDS
data found that 25 chemical products from four different MHC processes are considered reactive.
Unstable - As defined by OSHA (29 CFR 1910.1200[c]), a chemical is unstable if in the pure
state, or as produced or transported, will vigorously polymerize, decompose, condense, or will
become self-reactive under conditions of shock, pressure, or temperature. Only three chemical
products are reported as unstable according to MSDS data.
Sudden Release of Pressure - OSHA requires the reporting of chemical products that, while
stored in a container subjected to sudden shock or high temperature, causes a pressure increase
within the container that is released upon opening. MSDS data indicated only two chemical
products that are potential sudden release of pressure hazards.
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Table 3.36 Corrosive, Oxidizer, Reactive, Unstable, and Sudden Release of Pressure
Possibilities for MHC Processes
MHC Process
Carbon
Conductive Polymer
Electroless Copper
Graphite
Non-Formaldehyde
Electroless Copper
Palladium
Bath Type
Cleaner
Conditioner
Microetch
Catalyst
Conductive Polymer
Microetch
Accelerator
Catalyst
Cleaner/Conditioner
Electroless Copper
Microetch
Predip
Fixer
Graphite
Microetch
Accelerator
Electroless Copper
Microetch
Accelerator
Catalyst
Cleaner/Conditioner
Microetch
Other
Predip
Hazardous Property*
Corrosive
2(2)
3(3)
2(3)
2(3)
HI)
1(5)
5(10)
5(8)
11(25)
3(9)
4(6)
1(1)
1(3)
2(4)
2(6)
2(4)
4(10)
4(9)
1(6)
2(3)
1(4)
Oxidizer
2(2)
1(5)
5(9)
1(4)
1(2)
2(4)
Reactive
2(2)
3(5)
2(10)
2(8)
5(25)
2(9)
2(6)
1(2)
1(6)
2(4)
1(10)
1(9)
1(5)
Unstable
1(9)
1(4)
1(5)
Sudden Release
ofPressure i
1(9)
1(4)
Table entries are made in the following format - # of products meeting OSHA definition for the given hazardous
property as reported in the products' MSDSs (Total # of products in the process bath). A blank entry means that
none of the products for the specific process bath meet the OSHA reporting criteria for the given property.
Example: For the graphite process microetch bath, 2 (4) means that two of the four products in the bath were
classified as corrosive per OSHA criteria as reported by the products MSDSs.
3.5.3 MHC Chemical Product Health Hazards
A breakdown of MHC process baths that contain chemical products that are sensitizers,
acute or chronic health hazards, or irreversible eye damage hazards in their concentrated form is
presented in Table 3.37. Also discussed in this section are MHC chemical products that are
potential eye or dermal irritants and suspected carcinogens. The following presents OSHA
definitions for chemicals in these categories and discusses the data in Table 3.37 where
appropriate.
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Table 3.37 Sensitizer, Acute and Chronic Health Hazards, and Irreversible Eye Damage
Possibilities for MHC Processes
MHC Process
Carbon
Conductive Ink
Conductive Polymer
Electroless Copper
Graphite
Non-Formaldehyde
Electroless Copper
Organic-Palladium
Palladium
Bath Type
Carbon Black
Cleaner
Conditioner
Microetch
Other (Anti-Tarnish)
Print Ink
Catalyst
Conductive Polymer
Microetch
Accelerator
Anti-Tarnish
Catalyst
Cleaner/Conditioner
Electroless Copper
Microetch
Predip
Cleaner/Conditioner
Fixer
Graphite
Microetch
Accelerator
Catalyst
Electroless Copper
Microetch
Conductor
Microetch
Postdip
Accelerator
Catalyst
Cleaner/Conditioner
Microetch
Other
Acid Dip
Hazardous Property"
Sensitizer
2(6)
Acute Health
Hazard
3(4)
1(2)
3(3)
2(2)
2(2)
1(5)
2(4)
2(10)
1(8)
5(25)
3(9)
3(4)
2(3)
3(4)
1(2)
2(2)
3(6)
3(4)
1(10)
3(9)
1(6)
2(5)
2(3)
Chronic Health
Hazard
3(4)
1(2)
3(3)
2(2)
, 2(4)
2(10)
1(8)
4(25)
1(9)
2(4)
2(4)
2(2)
2(6)
1(4)
3(9)
2(5)
Irreversible
Eye Damage
4(4)
2(2)
2(3)
2(2)
2(2)
2(5)
3(3)
2(3)
1(1)
1(5)
2(4)
6(10)
3(8)
13 (25)
4(9)
5(6)
1(1)
1(3)
2(4)
4(6)
3(4)
2(2)
1(1)
1(1)
9(10)
4(9)
2(6)
3(5)
3(3)
1(1)
* Table entries are made in the following format - # of products meeting OSHA definition for the given hazardous
property as reported in the products' MSDSs (Total # of products in the process bath). A blank entry means that
none of the products for the specific process bath meet the OSHA reporting criteria for the given property.
Example: For the palladium process cleaner/conditioner bath, 2 (6) means that two of the six products in the bath
were classified as sensitizers per OSHA criteria as reported by the products MSDSs.
Sensitizer - A sensitizer is defined by OSHA [29 CFR 1910.1200 Appendix A (mandatory)] as a
chemical that causes a substantial proportion of exposed people or animals to develop an allergic
reaction in normal tissue after repeated exposure to the chemical. Only two chemical products
were reported as sensitizers by MSDS data, both palladium MHC process chemicals.
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Acute and Chronic Health Hazards - As defined by OSHA (29 CFR 1910.1200 Appendix A), a
chemical is considered a health hazard if there is statistically significant evidence based on at
least one study conducted in accordance with established scientific principles that acute or
chronic health effects may occur in exposed employees. Health hazards are classified using the
criteria below:
• Acute health hazards are those whose effects occur rapidly as a result of short-term
exposures, and are usually of short duration.
• Chronic health hazards are those whose effects occur as a result of long-term exposure,
and are of long duration.
Chemicals that are considered a health hazard include carcinogens, toxic or highly toxic
agents, reproductive toxins, irritants, corrosives, sensitizers, hepatotoxins, nephrotoxins,
nuerotoxins, agents which act on the hematopoietic system, and agents which damage the lungs,
skin, eyes, or mucous membranes.
A review of MSDS data found 51 chemical products reported as potentially posing acute
health hazards, and 33 chemical products potentially posing chronic health hazards. OSHA does
not require reporting of environmental hazards such as aquatic toxicity data, nor are toxicity data
on MSDSs as comprehensive as the toxicity data collected for the CTSA. OSHA health hazard
data are presented here for reference purposes only, and are not used in the risk characterization
component of the CTSA.
Carcinogen - As defined by OSHA (29 CFR 1910.1200 Appendix A), a chemical is considered
to be a carcinogen if: 1) it has been evaluated by the International Agency for Research on
Cancer (IARC), and found to be a carcinogen or potential carcinogen; 2) it is listed as a
carcinogen or potential carcinogen in the Annual Report on Carcinogens published by the
National Toxicology Program (NTP); or 3) it is regulated by OSHA as a carcinogen.
Formaldehyde, which is used as a reducing agent in the electroless copper process, is a suspected
human carcinogen. A review of MSDS data found that six chemical products were reported as
potential carcinogens. All of the products contain formaldehyde and are utilized hi the
electroless copper bath of the traditional electroless copper process.
Dermal or Eye Irritant - An irritant is defined by OSHA [29 CFR 1910.1200 Appendix A
(mandatory)] as a chemical, which is not corrosive, but which causes a reversible inflammatory
effect on living tissue by chemical action at the site of contact. A chemical is considered a
dermal or eye irritant if it is so determined under the testing procedures detailed in 16 CFR
1500.41- 42. A review of MSDS data found that all but six of the 181 MHC chemical products
reviewed are reported as either dermal or eye irritants.
Irreversible Eye Damage - Chemical products that, upon coming in contact with eye tissue, can
cause irreversible damage to the eye are required by OSHA to be identified as such on the
product's MSDS. A review of MSDS data found that 91 chemical products are reported as
having the potential to cause irreversible eye damage.
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3.5.4 Other Chemical Hazards
MHC chemical products that have the potential to form hazardous decomposition
products are presented below. In addition, chemical product incompatibilities with other
chemicals or materials are described, and other chemical hazard categories presented. The
following lists OSHA definitions for chemicals in these categories and summarizes the MSDS
data where appropriate.
Hazardous Decomposition - A chemical product, under specific conditions, may decompose to
form chemicals that are considered hazardous. With few exceptions, the MSDS data for the
chemical products in the MHC process indicate the possibility of decomposition to form a
potentially hazardous chemical. Each chemical product should be examined to determine its
decomposition products so that potentially dangerous reactions and exposures can be avoided.
The following are examples of hazardous decomposition of chemical products that are employed
in the MHC alternatives:
• When heated, a chemical product used to create an electroless copper bath can generate
toxic formaldehyde vapors.
• If allowed to heat to dryness, a graphite bath process chemical could result in gas releases
of ammonia, carbon monoxide, and carbon dioxide.
• Thermal decomposition under fire conditions of certain chemical bath constituents of a
palladium cleaner/conditioner bath can result in releases of toxic oxide gases of nitrogen
and carbon.
Incompatibilities - Chemical products are often incompatible with other chemicals or materials
with which they may come into contact. A review of MSDS data found that all of the MHC
processes have chemical products with incompatibilities that can pose a threat to worker safety if
the proper care is not taken to prevent such occurrences. Incompatibilities reported range from
specific chemicals or chemical products, such as acids or cyanides, to other materials, such as
rubber or textiles, like wood and leather. Chemical incompatibilities that are common to
products from all the MHC processes include acids, alkalis, oxidizers, metals, and reducing
agents. Incompatibilities were also found to exist between chemical products used on the same
process line. Individual chemical products for each process bath should be closely examined to
determine specific incompatibilities and care should be taken to avoid contact with incompatible
chemicals and chemical products, textiles, and storage containers.
The following are examples of chemical incompatibilities that exist for chemical products
that are employed hi the MHC alternatives:
:An electroless copper bath contains chemical products that, when contacted with
hydrochloric acid which is present in other electroless copper process baths, will result in
reaction forming bis-chloromethyl ether, an OSHA-regulated carcinogen.
Violent reactions can result when a chemical product of the conductive polymer catalyst
bath comes into contact with concentrated acids or reducing agents, both of which are
used in PWB manufacturing processes.
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• A microetch bath of a graphite process contains chemicals that will react to form
hazardous gases when contacted with other chemical products containing cyanides,
sulfides, or carbides.
• Hazardous polymerization of a particular conductive ink product can occur when the
product is mixed with chemicals products containing amines, anhydrides, mercaptans, or
imidazoles.
Other Chemical Hazard Categories - OSHA requires the reporting of several other hazard
categories on the MSDSs for chemicals or chemical products that have not already been
discussed above. These additional categories include chemical products that are:
• Water-reactive (react with water to release a gas that presents a health hazard).
• Pyrophoric (will ignite spontaneously in air at temperatures below 130° F).
• Stored as a compressed gas.
• Classified as an organic peroxide.
• Chemicals that have the potential for hazardous polymerization.
A review of MSDS data indicated that none of the chemical products are reported as
being water-reactive, pyrophoric, a compressed gas, an organic peroxide, or as having the
potential for hazardous polymerization.
3.5.5 Process Safety Concerns
Exposure to chemicals is just one of the safety issues that PWB manufacturers may have
to deal with during their daily activities. Preventing worker injuries should be a primary concern
for employers and employees alike. Work-related injuries may result from faulty equipment,
improper use of equipment, bypassing equipment safety features, failure to use personal
protective equipment, and physical stresses that may appear gradually as a result of repetitive
motions (i.e., ergonomic stresses). Any or all of these types of injuries may occur if proper
safeguards or practices are not in place and adhered to. An effective worker safety program
includes:
An employee training program.
Employee use of personal protective equipment.
Proper chemical storage and handling.
Safe equipment operating procedures.
The implementation of an effective worker safety program can have a substantial impact
on business, not only in terms of direct worker safety, but also in reduced operating costs as a
result of fewer days of absenteeism, reduced accidents and injuries, and lower insurance costs.
Maintaining a safe and efficient workplace requires that both employers and employees
recognize and understand the importance of worker safety and dedicate themselves to making it
happen.
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Employee Training
A critical element of workplace safety is a well-educated workforce. To help achieve this
goal, the OSHA Hazard Communication Standard requires that all employees at PWB
manufacturing facilities (regardless of the size of the facility) be trained in the use of hazardous
chemicals to which they are exposed. A training program should be instituted for workers,
especially those operating the MHC process, who may come into contact with, or be exposed to,
potentially hazardous chemicals. Training may be conducted by either facility staffer outside
parties who are familiar with the PWB manufacturing process and the pertinent safety concerns.
The training should be held for each new employee, as well as periodic retraining sessions when
necessary (e.g., when a new MHC process is instituted), or on a regular schedule. The training
program should explain to the workers the types of chemicals with which they work and the
precautions to be used when handling or storing them; when and how personal protection
equipment should be worn; and how to operate and maintain equipment properly.
Storing and Using Chemicals Properly
Because the MHC process requires handling of a variety of chemicals, it is important that
workers know and follow the correct procedures for the use and storage of the chemicals. Much
of the use, disposal, and storage information about MHC process chemicals may be obtained
from the MSDSs provided by the manufacturer or supplier of each chemical or formulation. Safe
chemical storage and handling involves keeping chemicals in their proper place, protected from
adverse environmental conditions, as well as from other chemicals with which they may react.
Examples of supplier recommended storage procedures found on the MSDSs for MHC chemicals
are listed below:
• Store chemical containers in a cool, dry place away from direct sunlight and other sources
of heat.
• Chemical products should only be stored in their properly sealed original containers and
labeled with the generic name of the chemical contents.
• Incompatible chemical products should never be stored together.
• Store flammable liquids separately in a segregated area away from potential ignition
sources or in a flammable liquid storage cabinet.
Some products have special storage requirements and precautions listed on their MSDSs
(e.g., relieving the internal pressure of the container periodically). Each chemical product should
be stored in a manner consistent with the recommendation on the MSDS. In addition, chemical
storage facilities must be designed to meet any local, state, and federal requirements that may
apply.
Not only must chemicals be stored correctly, but they must also be handled and
transported in a manner which protects worker safety. Examples of chemical handling
recommendations from suppliers include:
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• Wear appropriate protective equipment when handling chemicals.
• While transporting chemicals, do not use open containers.
• Use only spark-proof tools when handling flammable chemicals.
• Transfer chemicals using only approved manual or electrical pumps to prevent spills
created from lifting and pouring.
Proper chemical handling procedures should be a part of the training program given to
every worker. Workers should also be trained in chemical spill containment procedures and
emergency medical treatment procedures in case of chemical exposure to a worker.
Use of Personal Protective Equipment
OSHA has developed several personal protective equipment standards that are applicable
to the PWB manufacturing industry. These standards address general safety and certification
requirements (29 CFR Part 1910.132), the use of eye and face protection (Part 1910.133), head
protection (Part 1910.135), foot protection (Part 1910.136), and hand protection (Part 1910.138).
The standards for eye, face, and hand protection are particularly important for the workers
operating the MHC process where there is close contact with a variety of chemicals, of which
nearly all irritate or otherwise harm the skin and eyes. In order to prevent or minimize exposure
to such chemicals, workers should be trained in the proper use of personal safety equipment.
The recommended personal protective equipment for a worker handling chemicals is also
indicated on the MSDS. For the majority of MHC chemicals, the appropriate protective
equipment indicated by the MSDS includes:
• Goggles to prevent the splashing of chemical into the eyes.
• Chemical aprons or other impervious clothing to prevent splashing of chemicals on
clothing.
• Gloves to prevent dermal exposure while operating the process.
• Boots to protect against chemical spills.
Other items less widely suggested include chemically resistant coveralls and hats. In
addition to the personal protective equipment listed above, some MSDSs recommended that
other safety equipment be readily available. This equipment includes first aid kits, oxygen
supplies (SCBA), and fire extinguishers.
Other personal safety considerations are the responsibility of the worker. Workers should
be discouraged from eating or keeping food near the MHC process. Because automated
processes contain moving parts, workers should also be prohibited from wearing jewelry or loose
clothing, such as ties, that may become caught in the machinery and cause injury to the worker or
the machinery itself. In particular, the wearing of rings or necklaces may lead to injury.
Workers with long hair that may also be caught in the machinery should be required to securely
pull their hair back or wear a hair net.
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Use of Equipment Safeguards
In addition to the use of proper personal protection equipment for all workers, OSHA has
developed safety standards (29 CFR Part 1910.212) that apply to the actual equipment used in a
PWB MHC process. Among the safeguards recommended by OSHA that may be used for
conveyorized equipment are barrier guards, two-hand trip devices, and electrical safety devices.
Safeguards for the normal operation of conveyor equipment are included in the standards for
mechanical power-transmission apparatus (29 CFR Part 1910.219) and include belts, gears,
chains, sprockets, and shafts. PWB manufacturers should be familiar with the safety
requirements included in these standards and should contact their local OSHA office or state
technical assistance program for assistance in determining how to comply with them.
In addition to normal equipment operation standards, OSHA also has a lockout/tagout
standard (29 CFR Part 1910.147). This standard is designed to prevent the accidental start-up of
electric machinery during cleaning or maintenance operations that apply to the cleaning of
conveyorized equipment as well as other operations. OSHA has granted an exemption for minor
servicing of machinery provided the equipment has other appropriate safeguards, such as a
stop/safe/ready button which overrides all other controls and is under the exclusive control of the
worker performing the servicing. Such minor servicing of conveyorized equipment can include
clearing fluid heads, removing jammed panels, lubricating, removing rollers, minor cleaning,
adjusting operations, and adding chemicals. Rigid finger guards should also extend across the
rolls, above and below the area to be cleaned. Proper training of workers is required under the
standard whether lockout/tagout is employed or not. For further information on the applicability
of the OSHA lockout/tagout standard to MHC process operations, contact the local OSHA field
office.
Occupational Noise Exposure
OSHA has also developed standards (29 CFR Part 1910.95) that apply to occupational
noise exposure. These standards require protection against the effects of noise exposure when
the sound levels exceed certain levels specified in the standard. No data was collected on actual
noise levels from MHC process lines, but one PWB manufacturer suggested protective measures
may be needed to reduce noise levels from air knife ovens on carbon and graphite lines. This
manufacturer installed baffles on his system to reduce noise levels (Kerr, 1997).
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Chapter 4
Competitiveness
This chapter of the Cleaner Technologies Substitutes Assessment (CTSA) presents
information on basic issues traditionally important to the competitiveness of a printed wiring
board (PWB) manufacturer: the performance characteristics of the making holes conductive
(MHC) technologies relative to industry standards; the direct and indirect production costs
associated with the MHC technologies; the federal environmental regulations affecting chemicals
used in or waste streams generated by a technology; and the implications of an MHC technology
choice on global competitiveness. A CTSA weighs these traditional competitiveness issues
against issues business leaders now know are equally important: the health and environmental
impacts of alternatives products, processes, and technologies. Section 4.1 presents the results of
the Performance Demonstration Project. Section 4.2 presents a comparative cost analysis of the
MHC technologies. Section 4.3 lists the federal environmental regulations affecting chemicals in
the various technologies. Section 4.4 summarizes information pertaining to the international use
of the technologies, including reasons for adopting alternatives to electroless copper worldwide.
4.1 PERFORMANCE DEMONSTRATION RESULTS
4.1.1 Background
This section of the CTSA summarizes performance information collected during
performance demonstrations of MHC technologies. These demonstrations were conducted at 25
volunteer PWB facilities in the U.S. and Europe, between September and November, 1995.
Information from the performance demonstrations, taken hi conjunction with risk, cost, and other
information in this document, provides a more complete assessment of alternative technologies
than has previously been available from one source.
In a joint and collaborative effort, Design for the Environment (DfE) project partners
organized and conducted the performance demonstrations. The demonstrations were open to all
suppliers of MHC technologies. Prior to the start of the demonstrations, DfE project partners
advertised the project and requested participation from all interested suppliers through trade
shows, conferences, trade journals, and direct telephone calls.
4.1.2 Performance Demonstration Methodology
The detailed performance demonstration methodology is attached in Appendix F. The
general plan for the demonstrations was to collect information about MHC technologies at
facilities where the technologies were already in use. The information collected through the
demonstrations was intended to provide a "snapshot" of the way the technology was performing
at that particular facility at that particular time. It is important to note that the methodology was
developed by consensus by a technical workgroup, which included suppliers, trade association
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4.1 PERFORMANCE DEMONSTRATION RESULTS
representatives, the U.S. Environmental Protection Agency (EPA), and many PWB
manufacturers.
Each supplier was asked to submit the names of up to two facilities where they wanted to
see the demonstrations of their technology conducted. This selection process encouraged the
suppliers to nominate the facilities where their technology was performing at its best. This, in
turn, provided for more consistent comparisons across technologies. The sites included 23
production facilities and two supplier testing facilities. While there were no pre-screening
requirements for the technologies, the demonstration facilities did have to meet the requirements
of the performance demonstration methodology.
For the purposes of the Performance Demonstration project, the MHC process was
defined as everything from the desmear step through 0.1 mil of copper flash plating. In order to
minimize differences in performance due to processes outside this defined MHC function, the
panels used for testing were all manufactured and drilled at one facility. One hundred panels,
described below, were produced. After drilling, three panels were sealed in plastic bags with
desiccant and shipped to each test site to be processed through the site's MHC line. All bags
containing panels remained sealed until the day of processing.
An on-site observer from the DfE project team was present at each site from the point the
bags were opened until processing of the test panels was completed. Observers were present to
confirm that all processing was completed according to the methodology and to record data.
Each test site's process was completed within one day; MHC processing at all sites was
completed over a two month period.
When the MHC processing was completed, the panels were put into sealed bags with
desiccant and shipped to a single facility, where they remained until all the panels were collected.
At this facility, the panels were electroplated with 1.0 mil of copper followed by a tin-lead etch
resist, etched, stripped of tin-lead, solder mask coated, and finished with hot air solder leveling
(HASL). A detailed account of the steps taken in this process is included in Appendix F.
After HASL, the microsection coupons were routed out of the panels and sent to Robisan
Laboratory Inc. for mechanical testing. The Interconnect Stress Test (1ST) coupons were left in
panel format. The panels containing the coupons were passed twice through an IR reflow to
simulate assembly stress. A detailed protocol describing the IR reflow process is also included
in Appendix F. The panels with the 1ST coupons were then sent to Digital Equipment
Corporation of Canada (DEC Canada) for electrical prescreening and electrical testing.
Limitations of Performance Demonstration Methodology
This performance demonstration was designed to provide a snapshot of the performance
of different MHC technologies. Because the test sites were not chosen randomly, the sample
may not be representative of all PWB manufacturing facilities in the U.S. (although there is no
specific reason to believe that they are not representative). In addition, the number of test sites
for each type of technology ranged from one to ten. Due to the smaller number of test sites for
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4-2
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4.1 PERFORMANCE DEMONSTRATION RESULTS
some technologies, results for these technologies could more easily be due to chance than the
results from technologies with more test sites. Statistical relevance cannot be determined.
4.1.3 Test Vehicle Design
All of the test panels were manufactured by H-R Industries, Inc. The test panel measured
24 in. x 18 in., laminated to 0.062 in., with eight layers. Test panels were produced from B and
C stage FR4 materials. Artwork, lamination specifications, and a list of the steps taken to
manufacture the panels are included in Appendix F.
Each test panel contained 54 test coupons: 271ST coupons (used for electrical testing)
and 27 microsection coupons. 1ST coupons measured 6.5 in. x 3/4 in. and contained 700
interconnecting vias on a seven row by 100 via 0.050 in. grid. This coupon contained two
independent circuits: the post circuit and the plated through-hole (PTH) circuit. The post circuit
contained 200 interconnects, and was used to measure post interconnect resistance degradation.
The PTH circuit contained 500 interconnects, and was used to measure PTH (barrel) interconnect
resistance degradation. 1ST coupons had either 0.013 in. or 0.018 in. holes (finished).
The microsection coupon measured 2 in. x 2 in. and contained 100 interconnected vias on
a 10 row by 10 via 0.100 in. grid. It had internal pads at the second and seventh layer and a daisy
chain interconnect between the two surfaces of the coupon through the via. Microsection
coupons had either 0.013 in., 0.018 in., or 0.036 in. holes (finished).
This study was a snapshot based on products built with B and C stage FR4 materials and
this specific board construction. The data cannot necessarily be extrapolated to other board
materials or constructions.
4.1.4 Electrical and Microsection Testing Methodology
Electrical Testing Methodology
The 1ST coupons in panel format were electrically prescreened to determine defects on
arrival. The panels were then shipped to another facility for routing of the 1ST coupons, and
were shipped back to DEC Canada for completion of electrical testing.
Electrical testing was completed using the 1ST technology. 1ST is an accelerated stress
test method used for evaluating the failure modes of PWB interconnect. This method uses DC
current to create the required temperatures within the interconnect. There are three principal
types of information generated from the 1ST:
• Initial resistance variability.
Cycles to failure (barrel integrity).
• Post separation/degradation (post interconnect).
The resistance value for the first internal circuit (PTH circuit) for each coupon was
determined. This gives an indication of the resistance variability (plating thickness) between
4-3
DRAFT
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4.1 PERFORMANCE DEMONSTRATION RESULTS
coupons and between panels. The initial resistance testing was also used to determine which
coupons had defects on arrival, or were unsuitable for further testing.
The cycles to failure indicate how much stress the individual coupons can withstand
before failing to function (measuring barrel integrity). 1ST coupons contained a second internal
circuit (post circuit) used to monitor the resistance degradation of the post interconnect.
The level of electrical degradation in conjunction with the number of cycles completed is
used to determine the presence and level of post separation. The relative performance of the
internal circuits indicates which of the two internal circuits, the post circuit or the PTH circuit,
has the dominant failure mechanism. The draft Institute for Interconnecting and Packaging
Electronic Circuits (IPC) 1ST test method is included in Appendix F.
Mechanical Testing Methodology
The coupons for mechanical testing were sent to Robisan Laboratory, Inc. for testing.
Mechanical testing consisted of evaluations of metallurgical microsections of plated through
holes in the "as produced" condition and after thermal stress. One test coupon of each hole size
from each panel was sectioned. The direction the coupons were microsectioned was determined
by visually examining the coupons to determine the direction of best registration to produce the
most inner layer circuitry connections in the microsections.
Microsections were stressed per IPC-TM-650, method 2.6.8, included in Appendix F.
The plated through-holes were evaluated for compliance to the requirements found in IPC-RB-
276. Microsections were examined after final polish, prior to metallurgical microetch, and after
microetch.
The original test plan called for selection of 1ST and microsectioning coupons from
similar locations on each panel. Following prescreening, the coupon selection criteria was
amended to be based on coupons with the best registration. This resulted in some coupons being
selected from areas with known thicker copper (see Results of Electrical Prescreening below).
Four 0.013 in. 1ST coupons were selected from each of the three test panels from each
test site. Test Site #3 and Test Site #4 had only two available test panels, therefore six coupons
were selected from each panel. Three coupons from within six inches of the 1ST coupons
selected were microsectioned from the same panels. In some cases, the desired microsection
coupons exhibited misregistration, so next-best locations were used. In all cases, coupons
selected were located as close to the center of the panel as possible.
Limitations of Testing Methodology
Fine line evaluations in microsections have always been a point of contention within the
industry. Current microsection specifications state that any indication of separation between the
hole wall plating and the inner layer is sufficient grounds to reject the product. An indication of
post separation would be a line on the microsection thicker than what normally appears with
electroless copper technology (normal average: 0.02 - 0.04 mils). Separation may also be
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4-4
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4.1 PERFORMANCE DEMONSTRATION RESULTS
determined by a variation in the thickness of the line across the inner layer connection, especially
on electroless deposits that are very thin. The rationale for these rejection criteria is that product
with post separation degrades with time and temperature cycling.
With traditional electroless copper products where post separation is present, it can
usually be determined where the separation occurs: between the electroless and foil, within the
electroless, or between the electroless and the electrolytic plating. This determination often helps
in troubleshooting the plating process. In this study, some of the alternative technologies
resulted in no line at all after microetch on the microsections. This posed a problem in
interpretation of results. If traditional criteria are used to determine inner layer separation (i.e.,
the line of demarcation is thicker on some inner connects than others, and the electroless can be
seen as continuous between the inner layer and plated copper), then accurate evaluations of
product with no lines would not be possible. In this study, the criteria used on "no line" products
was that if the sections exhibited any line of demarcation after microetch, the product is
considered to have inner layer separation.
This issue is significant to the PWB industry because there remains a question about the
relationship between the appearance of a line on the microsection to the performance of a board.
Traditionally (with electroless copper products), the appearance of a line thicker than normal
electroless line is considered to be post separation, and the board is scrapped. However, there are
no criteria for how to evaluate "no line" products. In addition, there are no official means of
determining when "a little separation" is significant to the performance of the board.
1ST is not a subjective test and is not dependent upon the presence or absence of a line in
a microsection after microetch. The test provides a relative number of 1ST cycles necessary to
cause a significant rise in resistance in the post interconnect. This number of cycles may be used
to predict interconnect performance. Tests such as this, when correlated with microsections, can
be useful in determining how to interpret "no line" product characteristics. In addition, 1ST may
be able to determine levels of post separation.
The figures included in Appendix F in the IPC 1ST test method show various failure
mechanisms exhibited by different test sites and panels. Future industry studies must determine
the relevance of these curves to performance, based on number of cycles needed to raise the
resistance as well as the amount of change in resistance. Definitions for "marginal" and "gross"
separations may be tied to life-cycle testing and subsequently related to class of boards produced.
4.1.5 Results
Product performance for this study was divided into two functions: PTH cycles to failure
and the integrity of the bond between the internal lands (post) and the PTH. The PTH cycles to
failure observed in this study is a function of both electrolytic plating and the MHC process. The
results indicate that each MHC technology has the capability to achieve comparable (or superior)
levels of performance to electroless copper.
Results are presented in this section for all three stages of testing conducted:
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4-5
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4.1 PERFORMANCE DEMONSTRATION RESULTS
1. Electrical prescreening, which included tests for:
Defects on arrival based on resistance measurements.
Print and etch variability based on resistance distribution of the post circuit.
Plating variability based on resistance distribution of the PTH circuit.
2. Microsection evaluation, which examined:
• Plating voids.
• Drill smear.
• Resin recession.
• Post separation.
• Average copper plating thickness.
3. Interconnect stress testing, which measured:
• Mean cycles to failure of the PTH interconnect.
t • Post degradation/separation within the post interconnect.
Results of Electrical Prescreening
Seventy-four of 75 test panels from 25 test facilities were returned. One of the 74 proved
to be untestable due to missing inner layers. The results of the prescreening will be reported in
the following categories: defects on arrival (unacceptable for testing), print and etch variability,
and plating (thickness) variability.
Defects on Arrival. A total of 1,971 coupons from the 73 panels each received two
resistance measurements using a four wire resistance meter. The total number of holes tested
was 1.4 million. As shown in Table 4.1, one percent (19) of coupons were found to be defective,
and were considered unacceptable for 1ST testing because of opens and shorts.
Table 4.1 Defective Coupons Found at Prescreening
Test Site #
1
3
11
12
14
16
20
MHC Technology
Electroless
Electroless
Graphite
Graphite
Palladium
Palladium
Palladium
Opens
1
2
1
2
2
ShoHs 111
4
2
5
Following an inspection of the defective coupons, the opens were found to be caused by
voiding, usually within a single via. Shorts were caused by misregistration. The type of MHC
technology did not contribute to the shorts.
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4-6
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4.1 PERFORMANCE DEMONSTRATION RESULTS
Print and Etch Variability. The resistance distribution for the post circuit was
determined. Throughout manufacturing, the layers/panels were processed in the same
orientation, which provided an opportunity to measure resistance distributions for each
coupon/panel. The distribution proved very consistent. This result confirms that inner layer
printing and etching did not contribute to overall resistance variability. Table 4.2 depicts the
mean post circuit resistance for five 0.013 in. coupon locations (in milliohms) for all 73 panels.
Table 4.2 Mean Post Circuit Resistance Measurements, in Milliohms
(coupon locations on panel)
409
415
399
405
411
Plating Variability. The resistance distribution for the PTH circuit was determined as an
indicator of variability. The results indicated that overall resistance variability was due to plating
thickness variability rather than print and etch variability. Table 4.3 depicts the mean PTH
circuit resistance for five 0.013 in. coupon locations (in milliohms) for all 73 panels.
Table 4.3 Mean PTH Circuit Resistance Measurements, in Milliohms
(coupon locations on panel)
254
241
244
239
225:
The PTH interconnect resistance distribution showed the electrolytic copper plating
increased in thickness from the top to the bottom of each panel. Copper thickness variability was
calculated to be 0.0003 in. thicker at the bottom compared to the top of each panel. Resistance
variability, based on 54 measurements per panel, was also found from right to left on the panels.
Inconsistent drill registration or outer layer etching was thought to be the most probable cause of
this variability. When a number of holes break out of their pads, it increases the internal copper
area, causing the resistance to decrease. This reduction in resistance creates the impression the
coupons have thicker copper.
Table 4.4 lists the means and standard deviation of all PTH resistance measurements and
the levels of correlation among panels observed at each site. As seen in Table 4.4, copper plating
distribution at each site was good. Plating cells and rack/panel locations did not create large
variability that could affect the results of each test site. Because resistance (plating thickness)
distribution was also consistent among test sites, relative comparisons among the different MHC
technology sites can be made. Only one site, Test Site #12, was calculated to have poor
correlation between all three panels.
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4.1 PERFORMANCE DEMONSTRATION RESULTS
It was determined during correlation that the variations in hole wall plating thickness
indicated by electrical prescreening were due to variations hi the flash plate provided by each test
site and not due to variations in electrolytic plating.
Table 4.4 Prescreening Results - 0.013 in. Vias for All Test Sites8
Site#
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Mean Res.
239
252
238
232
236
266
253
230
243
248
226
240
231
247
243
239
240
245
226
229
250
256
253
239
224
StdBev.
14.5
17.6
12.5
11.2
12.1
15.7
14.2
11.6
10.6
13.0
19.0
23.0
16.0
26.8
11.1
15.9
12.8
9.7
10.2
10.2
13.3
8.8
12.5
12.0
13.9
, Pnl#l
234
269
227
224
239
255
240
221
247
256
216
254
243
256
236
232
247
245
223
219
258
256
257
241
210
Pnl#2
245
251
248
239
241
275
259
228
247
242
221
235
235
227
244
243
243
249
232
238
243
261
257
232
232
PnI#S
237
234
N/A
N/A
229
266
259
241
235
247
241
231
215
258
248
241
231
240
223
229
249
250
244
246
231
Corr,
All
2
All
All
2
2
All
2
2
All
2
None
2
All
2
All
All
All
2
2
2
All
All
All
All
* Site #6, an electroless copper site, may not have performed to its true capability on the day of the test. Due to a
malfunction in the line, the electroless copper bath was controlled by manual lab analysis instead of by the usual
single-channel controller.
Mean Res. - Mean resistance of all coupons on the three panels.
Std Dev. - Standard deviation for all coupons per test site.
Pnl # - Mean resistance for listed panel.
Corn. - Correlation Coefficient >.7 between each panel.
Sample size for each test site: 12.
Remaining test results will be reported for each type of MHC technology, represented by
the following test sites shown in Table 4.5.
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4-8
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4.1 PERFORMANCE DEMONSTRATION RESULTS
Table 4.5 Correlation of MHC Technologies with Test Site Numbers
Test Site #
1-7
8-9
10- 12
13-22
23-24
25
MHC Technology
Electroless Copper
Carbon
Graphite
Palladium
Non-Formaldehyde Electroless Copper
Conductive Polymer
# of Test Sites
7
2
3
10
2
1
Results of Microsection Evaluation
The only defects reported in this study were voids in hole wall copper, drill smear, resin
recession, and inner layer separation. Average hole wall thickness was also reported for each
panel. Defects present but not included as part of this report are registration, inner layer foil
cracks, and cracks in flash plating at the knees of the holes. These defects were not included
because they were not believed to be a function of the MHC technology. The inner layer foil
cracks appear to be the result of the drilling operation and not a result of z-axis expansion or
defective foil. None of the cracks in the flash plating extended into the electrolytic plate in the
coupons as received or after thermal stress. Therefore, the integrity of the hole wall was not
affected by these small cracks.
Plating Voids. There were no plating voids noted on any of the coupons evaluated. The
electrolytic copper plating was continuous and very even with no indication of any voids.
Drill Smear. The panels exhibited significant amounts of nailheading. Since
nailheading was present on all panels, it was determined that all test sites had received similar
panels to process and therefore, comparisons were possible. The main concern with the presence
of nailheading was that the amount of drill smear might be excessive compared to each test site's
"normal" product. Drill smear negatively impacts inner layer connections to the plated hole wall
if not removed.
Resin Recession. No samples failed current specification requirements for resin
recession. There was, however, a significant difference in the amount of resin recession among
test sites.
Inner Layer Separation. Different chemistries had different appearances after
metallurgical microetch. Electroless copper microsections traditionally have a definite line of
demarcation between foil copper and electrolytic copper after metallurgical microetch. This line
also appeared in electroless copper samples in this study. The line is the width of the electroless
deposit, and is very important in making a determination as to whether inner layers are separated
from the plated hole wall. Many of the products tested in this study had no line of demarcation
or lines which had little, if any, measurable width. For those MHC technologies that should not
have a line after microetch, the determination as to whether inner layer separation was present on
the samples was based on the presence of a line.
DRAFT
4-9
-------
4.1 PERFORMANCE DEMONSTRATION RESULTS
Over half of the test sites supplied product which did not exhibit inner layer separations
on as received or thermal stressed microsections. Some of the product exhibited inner layer
separation in the as received samples which further degraded after thermal stress. Other test sites
had product that showed very good interconnect as received and became separated as a result of
thermal stress.
The separations ranged from complete, very wide separations to very fine lines which did
not extend across the complete inner layer connection. No attempt was made to track these
degrees of separation because current specification requirements dictate that any separation is
grounds for rejection of the product.
Table 4.6 gives the percentage of panels from a test site that did or did not exhibit a
defect. The data are not presented by hole size because only Test Site #11 had defects on only
one size of hole. In all other test sites exhibiting defects, the defects were noted on all sizes of
holes.
Table 4.6 Proportion of Panels Exhibiting Defects
Test
Site#
1
2
3
4
5
6
7
8
9
10
11
12
13
, 14
15
16
17
18
19
20
21
22
23
24
25
Percentage of Panels
Exhibiting Defect
Drill Smr
0
66
0
100
0
0
0
0
0
0
0
0
0
0
0
0
33
0
0
0
0
0
0
0
0
ResRec
33
66
0
0
0
0
100
0
0
0
33
0
33
0
0
0
33
33
100
0
0
66
0
0
0
Post Sep
0
100
0
0
0
100
0
0
0
0
66
100
0
0
33
100
33
66
0
100
100
0
100
0
0
Percentage of Panels Exhibiting
Defect per Technology
(average of all test sites)
Drill Smr
21
0
0
3.3
0
0
Res Rec
31.6
0
11
26.5
0
0
Post Sep
31.6
0
55.6
43.3
50
0
MHC Technology
Electroless Copper
Carbon
Graphite
Palladium
Non-Formaldehyde
Electroless Copper
Conductive Polymer
DRAFT
4-10
-------
4.1 PERFORMANCE DEMONSTRATION RESULTS
Table 4.7 depicts the average measured copper plating thickness for all panels.
Table 4.7 Microsection Copper Plating Thickness (in mils)
Test Site
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Panel #1
1.4
0.95
1.3
1.3
1.2
1.1
1.5
1.3
1.2
1.0
1.5
1.3
1.2
1.2
1.1
1.1
1.2
1.1
1.5
1.6
1.1
1.2
1.4
1.3
1.4
Panel #2
1.1
1.1
1.1
1.2
1.3
1.1
1.1
1.3
1.4
1.1
1.5
1.3
1.3
1.1
1.1
1.2
1.3
N/A
1.3
1.4
1.2
1.1
1.1
1.2
1.7
Panel #3
1.2
1.3
N/A
N/A
1.3
1.1
1.1
1.2
1.3
1.3
1.1
1.3
1.3
1.2
1.2
1.3
1.4
1.5
1.3
1.3
1.2
1.1
1.2
1.2
1.4
Average Cut
1.24
1.11
1.2
1.25
1.24
1.1
1.2
1.3
1.3
1.14
1.4
1.3
1.3
1.2
1.13
1.2
1.3
1.3
1.4
1.4
1.14
1.13
1.24
1.23
1.5
Results of Interconnect Stress Testing
Test results will be reported in various formats. Both tables and graphs will be used to
describe 1ST cycles to failure for the PTH interconnect and post degradation/separation within
the post interconnect. 1ST was completed on a total of 12 coupons from each test site.
Mean Cycles to Failure Testing Results. The mean cycles to failure for the PTH
interconnect are established at the point when the coupon exceeds a ten percent increase in the
initial elevated resistance. Mean 1ST cycles to failure and standard deviation by test site are
shown in Table 4.8. Table 4.9 shows the mean 1ST cycles to failure and standard deviations by
MHC technology.
4-11
DRAFT
-------
4.1 PERFORMANCE DEMONSTRATION RESULTS
Table 4.8 Mean 1ST Cycles to Failure, by Test Site
Test Site # & MHC Technology Type
1 Electroless Copper
2 Electroless Copper
3 Electroless Copper
4 Electroless Copper
5 Electroless Copper
6 Electroless Copper
7 Electroless Copper
8 Carbon
9 Carbon
10 Graphite
11 Graphite
12 Graphite
13 Palladium
14 Palladium
15 Palladium
16 Palladium
17 Palladium
18 Palladium
19 Palladium
20 Palladium
21 Palladium
22 Palladium
23 Non-Formaldehyde Electroless Copper
24 Non-Formaldehyde Electroless Copper
25 Conductive Polymer
1ST Cycles to ¥ail
346
338
323
384
314
246
334
344
362
317
416
313
439
284
337
171
370
224
467
443
267
232
214
261
289
Standard Deviation
91.5
77.8
104.8
70
50
107
93.4
62.5
80.3
80
73.4
63
55.2
62.8
75.3
145.7
122.9
59.7
38.4
52.5
40.5
86.6
133.3
41.6
63.1
Sample size = 12 coupons from each site.
Table 4.9 Mean 1ST Cycles to Failure, by MHC Technology
MHC Technology
Electroless Copper
Carbon
Conductive Polymer
Graphite
Non-Formaldehyde Electroless Copper
Palladium
1ST Cycles to Fail
327
354
289
349
238
332
Standard Deviation
92.5
71
63.1
85.3
99.5
126
High standard deviations indicate that high levels of performance variability exist within
and among test sites.
DRAFT
4-12
-------
4.1 PERFORMANCE DEMONSTRATION RESULTS
Figures 4.1 through 4.6 identify the 1ST cycles to failure for each panel and test site for
each MHC technology. The two reference lines on each graph identify the mean cycles to failure
(solid line) for all 300 coupons tested (324 cycles) and the mean resistance (dotted line) for all
coupons measured (241 milliohms). When considering the overall performance of each panel, it
is useful to compare the mean resistance of the coupons to the dotted reference line. As
mentioned before, each test site was instructed to flash plate 0.0001 in. of electrolytic copper into
the holes. If the sites exceeded this thickness, the total copper thickness would be thicker,
lowering the resistance and increasing the performance of the panels. Therefore, panels with
lower resistance should be expected to perform better, and visa versa. Although each site was
requested to plate 0.0001 in. of electrolytic copper, the actual range was between 0.00005 in. and
0.0005 in.
Figure 4.1 Electroless Copper - 1ST Cycles to Fail vs. Resistance
500
450
400
UJ 350.
^ 300
M 25°
UJ
K 200
I 16°
100
50 •
0
1
1
L
• 1ST CYCLES
ORESISTANC
E
1
n
23456
TEST SITES
7
All electroless copper test sites had at least one panel that met or exceeded the mean
performance. As shown in Figure 4.1, for the panels that did not achieve the mean performance,
it can be seen that the mean resistance column was above the reference line (thinner copper).
The exception was Test Site #6, which exhibited a high degree of post separation (see post
separation results section below for an explanation of results). As noted previously, Test Site #6
may not have performed to its true capability on the day of the test. Due to a malfunction in the
line, the electroless copper bath was controlled by manual lab analysis instead of by the usual
single-channel controller.
DRAFT
4-13
-------
4.1 PERFORMANCE DEMONSTRATION RESULTS
Figure 4.2 Carbon - 1ST Cycles to Fail vs. Resistance
UJ
= uj
o o:
w 5
z +
500
450
400 •
350 •
300 •
250 •
200 •
150
100 •
50 -
• 1ST CYCLES
D RESISTANCE
TEST SITES
As shown in Figure 4.2, both carbon test sites had at least two panels that met or
exceeded the mean performance.
Figure 4.3 Graphite - 1ST Cycles to Fail vs. Resistance
Ul
CC
.4
600
450
400
350
3 Ul
U K 200
£2
55
100
60
0
• 1ST CYCLES
n RESISTANCE
10
11
TEST SITES
12
All three graphite test sites had at least one panel that met or exceeded mean
performance, as shown in Figure 4.3.
DRAFT
4-14
-------
4.1 PERFORMANCE DEMONSTRATION RESULTS
Figure 4.4 Palladium - 1ST Cycles to Fail vs. Resistance
I* Ul
«- o
t- <
11
5:
h- <
a S
z *
IS
500
450_
400
aBO
MO.
?sn
2jl9_
150
1pn
£0.
n
,
HIST CYCLES
RESISTANCE
13 14 15 16 17 18 19 20
_
21 22
TEST SITES
As shown in Figure 4.4, most palladium test sites had at least one panel that met or
exceeded the mean performance. Three test sites did not. Those test sites that did not achieve
the mean performance exhibited either high resistance or post separation.
Figure 4.5 Non-Formaldehyde Electroless Copper - 1ST Cycles to Fail vs. Resistance
•1ST CYCLES
DRESISTANCE
TEST SITES
Neither non-formaldehyde electroless copper test site met or exceeded mean
performance, as shown in Figure 4.5. Test Site #23 exhibited a high degree of post separation
(see post separation results section below for an explanation of results).
DRAFT
4-15
-------
4.1 PERFORMANCE DEMONSTRATION RESULTS
Figure 4.6 Conductive Polymer - 1ST Cycles to Fail vs. Resistance
500
11]
As shown in Figure 4.6, the single conductive polymer test site had one panel that met or
exceeded the mean performance.
Post Separation Testing Results
1ST determines post interconnect performance (post separation) simultaneously with the
PTH cycles to failure performance. The failure criteria for post separation has not been
established. Further work is in progress with the IPC to create an accept/reject criteria. For this
study, the 1ST rejection criteria is based on a 15 milliohm resistance increase derived from the
mean resistance degradation measurement for all 300 coupons tested.
A reliable post interconnect should measure minimal resistance degradation throughout
the entire 1ST. Low degrees of degradation (<15 milliohms) are common and relate to the
fatigue of the internal copper foils. Resistance increases greater than 50 milliohms were reported
as 50 milliohms. This was done hi order to avoid skewing results.
The mean resistance degradation of the post interconnect is determined at the time the
PTH failed. The readings (in milliohms) for the post interconnect and the standard deviations for
each test site (sample size =12 coupons from each site) and for each MHC technology are shown
in Tables 4.10 and 4.11, respectively.
DRAFT
4-16
-------
4.1 PERFORMANCE DEMONSTRATION RESULTS
Table 4.10 Mean Resistance Degradation of Post Interconnect, by Test Site
(in milliohms)
Tesf Site # and MHC Technology Type
1 Electroless Copper
2 Electroless Copper
3 Electroless Copper
4 Electroless Copper
5 Electroless Copper
6 Electroless Copper
7 Electroless Copper
8 Carbon
9 Carbon
10 Graphite
11 Graphite
12 Graphite
13 Palladium
14 Palladium
15 Palladium
16 Palladium
17 Palladium
18 Palladium
19 Palladium
20 "Palladium
21 Palladium
22 Palladium
23 Non-Formaldehyde Electroless Copper
24 Non-Formaldehyde Electroless Copper
25 Conductive Polymer
Post Degradation
13.1
17.2
6.6
6.7
3.8
34.8
4.1
2.8
2
5.2
8
16
9.5
2.8
7.9
32.2
0.8
7.6
4.7
13.7
40.5
4.5
47.9
4.2
2.8
Standard Deviation
3.5
12.9
3.7
2.7
2.4
13.1
4.6
2.9
2.5
3.9
8.1
15
4.7
2.6
7.4
18.1
1.8
6.4
3.3
5.6
11.3
2.6
7.2
1.9
1.8
Table 4.11 Mean Resistance Degradation of Post Interconnect, by MHC Technology
MHC Technology Type
Electroless Copper
Carbon
Conductive Polymer
Graphite
Non-Formaldehyde Electroless Copper
Palladium
Post Degradation
12.3
2.4
2.75
9.7
26
12.4
Standard Deviation
12.6
2.7
1.8
10.8
22.9
14.3
High standard deviations indicate that high levels of variability exist within and among
test sites and within an MHC technology.
DRAFT
4-17
-------
4.1 PERFORMANCE DEMONSTRATION RESULTS
Figures 4.7 through 4.12 identify the mean (average of four coupons per panel) 1ST post
resistance degradation results. The reference line on each graph identifies the mean resistance
degradation measurement for all 300 coupons tested (15 milliohms). If the mean resistance
degradation column is above the reference line, the panel had coupons that exhibited post
separation. The post resistance change was the value recorded at the point where the PTH
(barrel) failed.
Figure 4.7 Electroless Copper - Post Resistance Degradation
60
«-
Z
Ul *>•
1 -
u
U! 30 •
O W
o
a.
1S
10
iff III
u iJ
TEST SITES
As shown in Figure 4.7, two of the seven electroless copper test sites had at least one
panel that exhibited post separation. All three panels from Test Site #6 clearly exhibited gross
post separation. Both test methods for post separation failed all panels from Test Site #6. As
noted previously, Test Site #6 may not have performed to its true capability on the day of the
test. Due to a malfunction in the line, the electroless copper bath was controlled by manual lab
analysis instead of by the usual single-channel controller.
DRAFT
4-18
-------
4.1 PERFORMANCE DEMONSTRATION RESULTS
Figure 4.8 Carbon - Post Resistance Degradation
Ul
o
o
Ul
o
<0
55
Ul
cc
CO
o
o.
1
CO
O
j
z
45
40 •
35 -
30 -
25 -
20 -
10 -
5 -
0 -
• •
m •_ — •_
TEST SITES
No post separation was detected on any carbon panels, as shown in Figure 4.8.
Figure 4.9 Graphite - Post Resistance Degradation
11
TEST SITES
As shown in Figure 4.9, two of the three graphite test sites had at least one panel that
exhibited post separation.
DRAFT
4-19
-------
4.1 PERFORMANCE DEMONSTRATION RESULTS
MEAN POST RESISTANCE
CHANGE IN MILLIOHMS
Figure 4.10 Palladium - Post Resistance Degradation
50
45-
40-
35 -
30-
25-
20 =
15 =
:
Q
III ...
h
13 14 15 1
.. ill h. ll
J 17 18 19 20 2
ill
22
TEST SITES
As shown in Figure 4.10, four of the ten palladium test sites had at least one panel that
exhibited post separation. Test Site #16 and Test Site #21 clearly exhibited gross post
separation.
Figure 4.11 Non-Formaldehyde Electroless Copper - Post Resistance Degradation
24
TEST SITES
As shown in Figure 4.11, all three panels for non-formaldehyde electroless copper Test
Site #23 clearly exhibited gro^s post separation.
DRAFT
4-20
-------
4.1 PERFORMANCE DEMONSTRATION RESULTS
Figure 4.12 Conductive Polymer - Post Resistance Degradation
so
UJ
o
X
o
UI
o co
fc O 25
40
35
30
CO
O
O.
|
20
15
10
5
0
25
TEST SITE
No post separation was detected on any conductive polymer panels, as shown in
Figure 4.12.
4.1.6 Comparison of Microsection and 1ST Test Results
Microsection and 1ST were run independently, and test results were not shared until both
sets of data were completed and delivered to EPA. To illustrate the consistency of the test
results, Table 4.12 identifies both test methods and their results for post separation detection.
"Y" or "N" (yes or no) denote whether post separation was detected on any coupon or
panel from each test site. The "panels affected" column refers to how many of the panels within
each test site exhibited post separation. Test Site #17 was the only site with post separation
found in the microsection but not on 1ST.
Post separation results indicated percentages of post separation that were unexpected by
many members of the industry. It was apparent that all MHC technologies, including electroless
copper, are susceptible to this type of failure. The results of this study further suggest that post
separation may occur in different degrees. The level of post separation may play a role in
determining product performance; however, the determination of levels of post separation
remains to be discussed and confirmed by the PWB industry.
DRAFT
4-21
-------
4.1 PERFORMANCE DEMONSTRATION RESULTS
Table 4.12 IST/Microsection Data Correlation
Test Site #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Microsection
N
Y
N
N
N
Y
N
N
N
N
Y
Y
N
N
Y
Y
Y
Y
N
Y
Y
N
Y
N
N
Panels Affected
0
3
0
0
0
3
0
0
0
0
2
3
0
0
1
3
1
2
0
3
3
0
3
0
0
1ST
N
Y
N
N
N
Y
N
N
N
N
Y
Y
N
N
Y
Y
N
Y
N
Y
Y
N
Y
N
N
Panels Affected
0
3
0
0
0
3
0
0
0
0
1
2
0
0
1
3
0
2
0
2
3
0
3
0
0
DRAFT
4-22
-------
4.2 COST ANALYSIS
4.2 COST ANALYSIS
Operating an efficient and cost-effective manufacturing process with strict control of
material and production costs is the goal of every successful company. Fueled by consumer
demand for smaller and lighter electronics, rapid and continuous advances in circuit technology
make this goal a necessity for PWB manufacturers attempting to compete in today's global
marketplace. The higher aspect-ratio holes and tighter circuit patterns on current PWBs are
forcing manufacturers to continually evaluate and eventually replace aging manufacturing
processes that are unable to keep up with the ever-increasing technology threshold. When
coupled with the typically slim profit margins of PWB manufacturers, these process changes
represent a major capital investment to a company and emphasize the importance of selecting an
efficient, cost-effective process that will allow the company to remain competitive. As a result,
manufacturers are seeking comprehensive and more detailed cost data before investing in
alternative processes.
This section presents a comparative cost analysis of the MHC technologies. Costs were
developed for each technology and equipment configuration (vertical, immersion-type
equipment, or horizontal, conveyorized equipment) for which data Were available from the
Workplace Practices Survey and Performance Demonstration. Table 4.13 presents the processes
(alternatives and equipment configurations) evaluated.
Table 4.13 MHC Processes Evaluated in the Cost Analysis
MHC Alternative
Electroless Copper
Carbon
Conductive Polymer
Graphite
Non-Formaldehyde Electroless Copper
Organic-Palladium
Tin-Palladium
Nott-Ctatvtyorized
•
•
•
•
Conveyorized ;
•
•
•
•
•
•
Costs were analyzed using a cost model developed by the University of Tennessee
Department of Industrial Engineering. The model employs generic process steps and functional
groups (see Section 2.1, Chemistry and Process Description of MHC Technologies) and typical
bath sequences (see Section 3.1, Source Release Assessment) for each process alternative.
Figure 4.13 presented the generic process steps and typical bath sequences. To develop
comparative costs on a $/surface square foot (ssf) basis, the cost model was formulated to
calculate the cost of performing the MHC function on a job consisting of 350,000 ssf. This is the
average annual throughput for facilities in the Workplace Practices Survey database. The cost
for each process is compared to a generic non-conveyorized electroless copper process, defined
here as the baseline process.
DRAFT
4-23
-------
4.2 COST ANALYSIS
§
•a
o
U
o
to
1
I
f
CO
1V i ••> f
/•*
;•> t H
^ ) \ •*•!
f T I'v'i
-* H
, ^^ fl
' - ^~,^,^1-, a' t
DRAFT
4-24
-------
4.2 COST ANALYSIS
The overall objective of this analysis was to determine the comparative costs of the MHC
technologies using a cost model that adheres to fundamental principles of cost analysis. Other
objectives were to make the analysis flexible and to consider environmental costs. The cost
model was designed to estimate the comparative costs of fully operational MHC process lines. It
does not estimate start-up costs for a facility switching to an alternative MHC technology or the
cost of other process changes that may be required to implement a new MHC technology.
Section 4.2.1 gives an overview of the cost methodology. Section 4.2.2 presents simulation
model results. Section 4.2.3 describes details of the cost methodology and presents sample cost
calculations. Section 4.2.4 contains analysis results, while Section 4.2.5 presents a sensitivity
analysis of the results. Section 4.2.6 presents conclusions.
4.2.1 Overview of the Cost Methodology
The costs of the MHC technologies were developed by identifying the steps in each
process, breaking each step down into its cost components, and determining the cost of each
component. Component costs were determined utilizing traditional costing mechanisms,
computer simulation, and ABC. Computer simulation was used to replicate each of the MHC
processes to determine the time required to complete the specified job and other job-specific
metrics. ABC is a cost accounting method that allocates indirect or overhead costs to the
products or processes that actually incur those costs. Activity-based costs are determined by
developing bills of activities (BO As) for tasks essential to the process. A BOA is a listing of the
component activities involved in the performance of a certain task, together with the number of
times each component activity is performed. The BOA determines the cost of a task by
considering the sequence of actions and the resources utilized while performing that task.
Framework for the Cost Formulation
Figure 4.14 presents the hybrid cost formulation framework used in this analysis. The
first step in the framework was to develop or define the alternatives to be evaluated. The generic
process descriptions, chemical baths, typical bath sequences, and equipment configurations were
defined in Table 4.13 and Figure 4.13. This information was used to identify critical variables
and cost categories that needed to be accounted for in the cost analysis. Cost categories were
analyzed to identify the data required to calculate the costs (i.e., unit costs, utilization or
consumption rates, criteria for performing an activity, such as chemical bath replacement, the
number of times an activity is performed, etc.). For each process, a computer simulation was
then developed using ARENA® computer simulation software and information derived from the
cost components. The simulations were designed to model a MHC manufacturing job consisting
of 350,000 ssf.
DRAFT
4-25
-------
4.2 COST ANALYSIS
Figure 4.14 Hybrid Cost Formulation Framework
MHC
Alternatives
Development of
Cost Categories
Development of
Simulation Model
_L
Traditional Costs
Components
Activity-Based Cost
Components
Cost
Analysis
Sensitivity
Analysis
Simulation modeling provides a number of advantages to the cost analysis, including the
following:
• Simulation modeling can replicate a production run on the computer screen, allowing an
analyst to observe a process when the actual process does not exist. In this case, the
generic MHC technologies, as they are defined in Figure 4.13, may not exist within any
one facility.
• Simulation allows for process-based modifications and variations, resulting in inherent
flexibility within the system. Simulation models can be designed to vary the sequence of
operations, add or delete operations, or change process times associated with operations,
materials flows, and other variables.
• Data gathered from survey results, chemical suppliers, and the Performance
Demonstration have some data gaps and inconsistencies. However, these data must be
aggregated to develop comparative costs of the generic MHC alternatives. Thus, data
collected from one or more facilities may not fully represent a generic MHC alternative
or group of alternatives. Process simulation based on fundamental assumptions and data
helps clear up data inconsistencies and fill data gaps.
• Simulation enables one to study the sensitivity of critical performance measures to
changes in underlying input variables. Constant input variables may be modified in the
sensitivity analysis to determine the uncertainty (in terms of probability distributions)
associated with these input variables.
DRAFT
4-26
-------
4.2 COST ANALYSIS
Direct results of the simulation model and results derived from simulation outputs include
the following:
• The amount of time the MHC line operates to produce the job.
• The number of tunes an activity is performed during the course of the job.
• Consumption rates (e.g., water, energy, and chemical consumption).
• Production rates (e.g., wastewater generation).
Simulation results were combined with traditional cost components to adjust these costs
for the specified job. An example of this is the determination of equipment cost. Simulation
results were used to calculate a utilization ratio (UR), defined as the amount of time in days
required to produce 350,000 ssf divided by one operating year (defined as 250 days). Annualized
equipment costs were determined utilizing industry sources for equipment price and depreciation
guidelines from the Internal Revenue Service. These costs were multiplied by the UR to
determine the equipment costs for the job being evaluated.
Activity-based costs were determined by combining simulation results for the frequency
of activities with the cost of an activity developed on a BOA. For example, the activity costs of
replacing a particular bath were determined by developing a BOA, developing costs for each
activity on the BOA, and multiplying these costs by the number of bath replacements required to
complete a job of 350,000 ssf. In this manner, the overall analysis combines traditional costs
with simulation outputs and activity-based costs. The effects of critical variables on the overall
costs were then evaluated using sensitivity analysis.
Cost Categories
Table 4.14 summarizes the cost components considered in this analysis, gives a brief
description of each cost component and key assumptions, and lists the primary sources of data
for determining the costs. Section 4.2.3 gives a more detailed accounting of the cost
components, including sample cost calculations for each component.
In addition to traditional costs, such as capital, production, and maintenance costs, the
cost formulation identifies and captures some environmental costs associated with the
alternatives. In this regard, both simulation and ABC assist in analyzing the impact of the MHC
alternatives on the environment. Specifically, the amounts of energy and water, consumed as
well as the amount of wastewater generated are determined for each MHC alternative.
Environmental costs that could not be quantified include wastewater treatment and solid waste
disposal costs. Also, the costs of defective boards and the consequent waste of resources were
not quantified. These costs are discussed in more detail, below.
DRAFT
4-27
-------
4.2 COST ANALYSIS
a
0
ft
S
o
U
1
U
T-t
*
O
1
Sources of Cost Data
Description of Cost Component
fi
S o
§ U
a
ll
Number of rinse tanks and daily water usage per tanl
Section 5.1, Resource Conservation; days to comple
simulation.
0 &
en na
Water consumption costs based on number of rii
per process line; daily water usage per tank, and
complete job.
1
¥
s
£P
Daily electricity consumption from Section 5.2, Ene
days to complete job from simulation.
t
Electricity costs based on daily electricity consu
by MHC equipment and days to complete job.
Electricity
1
£
6
Daily natural gas consumption from Section 5.2, En<
days to complete job from simulation.
&
00 D,
Natural gas consumption based on daily natural
consumption from drying ovens (carbon and gra
processes only) and days to complete job.
1
O
1
>,
—3 tn
•O 0
D U
t
Not quantified; assumed to be the same for all altern
!
O
Cost for permit to discharge wastewater to publi
owned treatment works (POTW).
.t!
POTW Perm
£,
%
ti S
ta -a
Not quantified; pretreatment costs are expected to di
significantly among the alternatives, but insufficient
available to reliably estimate these costs.
i
P-I
Cost to pretreat wastewater prior to discharge to
Wastewater
Pretreatment
Cost
|^
? 5
Quantity of wastewater discharged assumed equal to
usage; discharge fees based on fees charged by Kno:
Tennessee Utility Board (KUB).
1
3
Fees for wastewater discharge assessed by local
Wastewater
Discharge
Costs
i
u
J8 g
^ o
DRAFT
4-28
-------
4.2 COST ANALYSIS
I
\
\
*
1
d
i
o
Bl
o
*****
o
i
f
ft
c
8
3
I
fc
"5 5
Q 3
.^^ ff
U
? «-
Number of line operators based on Workplace Practices Sun
data and site visits; days to produce job from simulation; lab<
rate = $10.22/hr based on published data.
Q
* § I
8 1 £>
(-, .22 o3 "«
Labor costs for line operator, excluding labo
maintenance activities (included under main
costs). Assumes one line operator per day p
conveyorized process, 1.1 line operators per
non-conveyorized process.
1
Cost of transporting materials from BOA; number ot bath
replacements required from simulation.
Cost to transport chemicals required for batt
replacement from storage to process line.
o
'-53 v
"tj
0 cu
&|
«
o
1
"0 -K
2 o
£ u
Cost to clean up tank from BOA; number ot bath cleanups
(replacements) required from simulation.
n
|
j3
3
0 «-
Labor and materials (excluding replacement
costs to clean up a chemical tank during batl
replacement.
ex
i
CO
O
H
i
3
)
en
3
H
3
D
i
i
m
5
?|
" g
2 'en
t* g
o o
0 *
If
^
13
o
Labor and equipment costs to set up a chem
after bath replacement.
ex
3
§
i
pa
C/3
£»•!
Assumes analytical work done m-house. Cost for one activi
from BOA; annual number of samples from Workplace Prac
Survey adjusted using URa.
*4-4
0
.22
.i?
S
i
Labor and materials costs for sampling and :
chemical baths.
•o
§
M en
= '«
'p[ ?^*
C/3 <
3 Si
^abor cost for one activity from BOA; annual number ot lilt
1 replaced from Workplace Practices Survey adjusted using U
Labor costs for replacing bath filters.
^
-------
4.2 COST ANALYSIS
Wastewater Treatment and Sludge Disposal Costs. PWB manufacturing consists of a
number of process steps (see Section 1.2.3 for an overview of rigid multi-layer PWB
manufacturing). In addition to the MHC process line, these steps include electroplating
operations and other steps which consume large quantities of rinse water and, consequently,
generate large quantities of wastewater. Most PWB manufacturers combine the effluents from
various process lines into one wastewater stream which is treated on-site in a continuous process
prior to discharge. As part of the Pollution Prevention and Control Survey (EPA, 1995a), PWB
manufacturers were asked to provide the following about their on-site wastewater treatment
facility:
• A process flow diagram for wastewater treatment.
• The quantity of sludge generated from wastewater treatment.
• The percent solids of the sludge.
• The costs of on-site wastewater treatment.
• The method and costs of sludge recycle and disposal.
Capital costs for wastewater treatment ranged from $1.2 million for a system purchased
in 1980 with a capacity of 135 gallons per minute (gpm) to $4,000 for a system purchased in
1987 with a capacity of nine gpm. Costs for operating an on-site wastewater treatment system
were as high as 3.1 percent of total annual sales. The median cost for wastewater treatment
operation was 0.83 percent and the average was 1.02 percent of annual sales.
Wastewater treatment sludges from PWB electroplating operations are classified as an
F006 hazardous waste under the Resources Conservation and Recovery Act (RCRA); most
facilities combine effluents from the electroplating line with other process wastewaters. Eighty-
eight percent of respondents to the Survey reported that wastewater treatment sludges are sent to
an off-site recycling facility to recover the metals. The average and median costs for off-site
recovery of sludge were $0.48/lb and $0.21/lb, respectively. In general, the lower costs
experienced by some respondents compared to others were due to larger-size shipments and
shorter distances to the recycling sites. In some cases, respondents whose sludge had a higher
solids content also reported lower costs; dewatered sludge has a higher recovery value.
Eighty-six percent of Survey respondents used an electroless copper MHC process, 14
percent used a palladium-based process (the survey did not distinguish between tin- and organic-
palladium processes), and one respondent used a graphite process. None of the other MHC
alternatives were represented in the Survey.
The Workplace Practices Survey attempted to characterize costs by collecting
information about the percent the MHC line contributes to overall wastewater and sludge
generation rates. However, most manufacturers were unable to provide this information and the
data that were reported were of variable to poor quality.
Since the MHC line is only one of several process lines that discharge effluent to
wastewater treatment and because little or no information is available on the contribution of the
MHC line to overall wastewater effluents, on-site wastewater treatment and sludge disposal costs
DRAFT
4-30
-------
4.2 COST ANALYSIS
could not be reliably estimated. However, costs of wastewater treatment and sludge disposal are
expected to differ significantly among the alternatives. For example, the presence of the chelator
EDTA in electroless copper wastewater discharges makes these effluents more difficult to treat.
However, complexing agents, such as the ammonia found in other PWB manufacturing steps,
also adversely affect the treatability of wastewater.
Other Solid Waste Disposal Costs. Two other types of solid wastes were identified that
could have significantly different waste disposal costs among the alternatives: filter disposal cost
and defective boards disposal costs. Table 4.15 presents the number of filters that would be
replaced in each process during a job of 350,000 ssf. These data are based on data from the
Workplace Practices Survey and a UR calculated for each process from simulation results.
(Simulation results are discussed further in Section 4.2.2.) While these results illustrate that the
number of waste filters generated by the alternatives differ significantly, no information is
available on the characteristics of the filters used hi alternative processes. For example, the
volume or mass of the filters and waste classification of the filters (hazardous or non-hazardous)
would significantly affect the unit cost for disposal. Therefore, filter disposal costs were not
estimated.
Table 4.15 Number of Filter Replacements by MHC Process
MHC Process
Electroless Copper, non-conveyorized (BASELINE)
Electroless Copper, conveyorized
Carbon, conveyorized
Graphite, conveyorized
Conductive Polymer, conveyorized
Non-Formaldehyde Electroless Copper, non-conveyorized
Organic-Palladium, non-conveyorized
Organic-Palladium, conveyorized
Tin-Palladium, non-conveyorized
Tin-Palladium - conveyorized
Filter Replacements
per Year"
100
100
20
103
74
17
50
50
74
74
Filter Replacements
per tJobb
160
35
7
52
21
12
22
16
35
19
90th percentile data based on Workplace Practices Survey data. Data not adjusted for throughput or to account for
differing maintenance policies at individual PWB manufacturing facilities.
b Based on simulation results for a job of 350,000 ssf.
The number of defective boards produced by an alternative has significance not only from
the standpoint of quality costs, but also from the standpoint of waste disposal costs. Clearly, a
higher defect rate leads to higher scrap and, therefore, waste of resources. However, as discussed
in Table 4.14, the Performance Demonstration showed that each of the alternatives can perform
at least as well as the electroless copper process, if operated according to specifications. Thus,
for the purposes of this analysis, no differences would be expected in the defect rate or associated
costs of the alternatives.
DRAFT
4-31
-------
4.2 COST ANALYSIS
Simulation Model Assumptions and Input Values
Appendix G presents a graphic representation of the simulation models developed for
each of the MHC alternatives. The assumptions used to develop the simulation models and
model input values are discussed below.
Assumptions. Several assumptions used in the simulation model are based on the
characteristics of a model facility presented in the Source Release Assessment and Exposure
Assessment (Sections 3.1 and 3.2, respectively). Assumptions include the following:
• The facility operates an MHC line 250 days/year, one shift/day. Many facilities operate
two shifts, but the Exposure Assessment and this analysis use first shift data as
representative. This assumption could tend to underestimate labor costs for companies
that pay higher rates to second shift workers. Or it could tend to overestimate equipment
costs for a company running two shifts and using equipment more efficiently. However,
since this assumption is used consistently across alternatives, the effects on the
comparative cost results are expected to be minor.
• The MHC process line operates an average of 6.8 hrs/shift.
• The MHC line is down at least 1.2 hours per day for start-up time and for maintenance,
including lubricating of equipment, sampling of baths, and filter replacement.
• Additional down time occurs when the MHC line is shut down to replace a spent or
contaminated bath.
• PWB panels that have been processed up to the MHC step are available whenever the
MHC process line is ready for panels.
• If a chemical bath is replaced at the end of the day, such that the amount of time required
to replace the bath exceeds the time remaining in the shift hours, employees will stay
after hours and have the bath ready by the beginning of the next shift.
• The entire MHC process line is shut down whenever a bath requires replacing, but
partially processed racks or panels are finished before the line is shut down.
* The MHC process only shuts down at the end of a shift and for bath replacement.
• The process is empty of all panels or racks at the end of each shift and starts the process
empty at the beginning of a shift.
Further simulation assumptions have to be defined separately for conveyorized and non-
conveyorized systems. Conveyorized MHC process assumptions are as follows:
• The size of a panel is 17.7 in. x 22.9 in. (from Workplace Practices Survey data for
conveyorized processes).
• Panels are placed on the conveyor whenever space on the conveyor is available, and each
panel requires 18 niches (including space between panels).
• Conveyor speed is constant, thus, the volume (gallons) of chemicals in a bath varies by
bath type (i.e., microetch, conditioner, etc.) and with the length of the process step (e.g.,
bath or rinse tank) to provide the necessary contact time (see Table 4.16 for bath
volumes).
DRAFT
4-32
-------
4.2 COST ANALYSIS
The conveyor speed, cycle time, and process down time are critical factors that determine
the time to complete a job.
Table 4.16 Bath Volumes Used for Conveyorized Processes
Chemical bath
Cleaner/Conditioner
Cleaner
Carbon
Graphite
Conditioner
Polymer
Microetch
Predip
Catalyst ,
Accelerator
Conductor
Electroless Copper
Post Dip
Acid Dip
Anti-Tarnish
Electroless
Copper
65
NA
NA
NA
NA
NA
64
50
139
80
NA
185
NA
79
39
Bath Volume by MHC Alternative (gallons)
Carbon
NA
44
128
NA
56
NA
64
NA
NA
NA
NA
NA
NA
NA
NA
Conductive
Polymer
65
NA
NA
NA
NA
26
64
NA
139
NA
NA
NA
NA
NA
NA
Graphite
65
NA
NA
37
NA
NA
64
NA
NA
NA
NA
NA
NA
NA
NA
Organic-
Palladium
NA
44
NA
NA
56
NA
64
50
NA
NA
108
NA
45
79
NA
Tin-
Palladium
65
NA
NA
NA
NA
NA
64
59
139
80
NA
NA
NA
79
NA
NA: Not Applicable.
Non-conveyorized MHC process assumptions are as follows:
The average volume of a chemical bath is 75 gallons (from Workplace Practices Survey
data for non-conveyorized processes).
• Only one rack of panels can be placed in a bath at any one time.
• A rack contains 20 panels (based on Workplace Practices Survey data, including the
dimensions of a bath, the size of a panel, and the average distance between panels in a
rack).
The size of a panel is 16.2 in. x 21.5 in. to give 96.8 ssf per rack.
• The frequency at which racks are entered into the process is dependent upon the
bottleneck or rate limiting step.
• The duration of the rate limiting step, cycle time, and process down time are critical
factors that determine the time to complete a job.
Inputs Values. Input values for the critical factors identified above (cycle time, down
time, and conveyor speed for conveyorized processes, and. cycle time, down time, and duration of
rate limiting step for non-conveyorized processes) were developed from Workplace Practices
Survey data and Product Data Sheets prepared by suppliers which describe how to mix and
maintain chemical baths. Tables 4.17 and 4.18 present time-related inputs to the simulation
models for non-conveyorized and conveyorized processes, respectively.
DRAFT
4-33
-------
4.2 COST ANALYSIS
Table 4.17 Time-Related Input Values for Non-Conveyorized Processes
Non-Conveyorized
MHC Alternative
Electroless Copper
Non-Formaldehyde
Electroless Copper
Organic-Palladium
Tin-Palladium
Time Required to
Replace a Bath"
(minutes)
180
30
180
108
Rate Limiting
Bath
Electroless Copper
Electroless Copper
Accelerator
Conductor
Time in Rate
Limiting B;ith°
(minutes)
34
16
9.2
5.3
Process Cycle
TMe*
(minutes)
48
51 ,
30
52
products from more than one supplier. For example, five suppliers of electroless copper chemical products
participated in the project. Input values may underestimate or overestimate those of any one facility, depending on
factors such as individual operating procedures, the chemical or equipment supplier, and the chemical product used.
b 90th percentile value used in the Exposure Assessment from Workplace Practices Survey data (see Section 3.2).
Used to calculate down time.
c Average values from the Workplace Practices Survey.
Table 4.18 Time-Related Input Values for Conveyorized Processes
Conveyorized MHC
Alternative
Electroless Copper
Carbon
Conductive Polymer
Graphite
Organic-Palladium
Tin-Palladium
Time Required to
Replace a Bathb
(minutes)
180
180
180
219
108
180
Length of
Conveyor"
(feet)
71
,31
34
27
50
47
Process Cycle
Timec
{minutes)
15
13
8.0
7.8
15
8.6
Conveyor
Speed d
(ft/milt)
4.7
2.4
4.3
3.5
3.3
5.5
products from more than one supplier. For example, five suppliers of electroless copper chemical products
participated in the project Input values may underestimate Or overestimate those of any one facility, depending on
factors such as individual operating procedures, the chemical or equipment supplier, and the chemical product used.
b 90th percentile value used in the Exposure Assessment from Workplace Practices Survey data (see Section 3.2).
Used to calculate down time.
c Average values from Workplace Practices Survey.
A Conveyor speed = length of conveyor -*- process cycle time.
The input values for the time required to replace a bath time (in Tables 4.17 and 4.18) are
used together with bath replacement criteria in the calculation of down time. Suppliers provide
instructions with their products (called Product Data Sheets for the purposes of this project) that
describe when a bath should be replaced because it is expected to be spent or too contaminated to
be used. These replacement criteria are usually given in one of three forms:
As a bath capacity in units of ssf per gallon of bath.
As a concentration-based criterion that specifies an upper concentration limit for
contaminants in the bath, such as grams of copper per liter in the microetch bath,
As elapsed time since bath creation.
DRAFT
4-34
-------
4.2 COST ANALYSIS
Bath replacement criteria submitted by suppliers were supplemented with Workplace
Practices Survey data and reviewed to determine average criteria for use in the simulation
models. Criteria in units of ssf/gallon were preferred because these can be correlated directly to
the volume of a bath. Once criteria in ssf/gallon were determined, these were converted to units
of racks per bath replacement for non-conveyorized processes and panels per bath replacement
for conveyorized processes. The converted values were used as inputs to the simulation models.
As an example, Table 4.19 presents bath replacement criteria used to calculate input values for
electroless copper processes. Appendix G presents the different bath replacement criteria
recommended by chemical suppliers, and the input values used in this analysis.
Table 4.19 Bath Replacement Criteria for Electroless Copper Processes
Chemical Bath
Cleaner/Conditioner
Microetch
Predip
Catalyst
Accelerator
Electroless Copper
Acid Dip
Anti-Tarnish
Bath Replacement Criteria*
(sstfgal)
510
250
540
Replace once per year
280
430
675
325
Values were selected from data provided by more than one electroless copper chemical supplier. To convert to
units of racks per bath replacement for non-conveyorized processes, multiply by 75 gallons (the average bath size)
and divide by 96.8 ssf (ssf per rack). To convert to units of panels per bath replacement for conveyorized processes,
multiply by the bath size in gallons and divide by 5.6 ssf/panel.
Activity-Based Costing (ABC)
As discussed previously, ABC is a method of allocating indirect or overhead costs to the
products or processes that actually incur those costs. Activity-based costs are determined by
developing BOAs for critical tasks. A BOA is a listing of the component activities involved in
the performance of a certain task, together with the number of times each component activity is
performed. The BOA determines the cost of a task by considering the sequence of actions and
the resources utilized while performing that task. In this analysis, the costs of critical tasks
determined by a BOA are combined with the number of times a critical task is performed,
derived from simulation results to determine the total costs of that activity.
BOAs were developed for the following critical tasks performed within MHC
alternatives:
• Chemical transport from storage to the MHC process.
• Tank cleanup.
• Bath setup.
• Bath sampling and analysis.
• Filter replacement.
DRAFT
4-35
-------
4.2 COST ANALYSIS
These BOAs were developed based on information developed for earlier projects
involving similar tasks and on information gathered through site visits and general process
knowledge. The following discussion uses the BOA for chemical transport, presented in Table
4.20, as an example of how BOAs were developed and used. Appendix G presents the BOAs for
other activities.
Key assumptions were developed to set the limits and to designate the critical activity's
characteristics. For chemical transport, the assumptions were:
• Chemical costs are not included in the BOA, but are considered within material costs.
* The portion of labor costs considered are not included within production costs.
• Labor rate used is $ 10.22 per hour, consistent with the labor rate for an operator level job.
• Multiple chemicals are required for each bath replacement.
• All chemicals for a bath replacement are transported on one forklift trip.
• Chemicals are purchased in containers larger than the line containers used to move
chemicals to the MHC process.
• All chemicals are stored in a central storage location.
• Chemicals are maintained in central storage via inventory tracking and physical
monitoring.
• A forklift costs $580/month or $0.06/minute, including leasing, maintenance, and fuel.
• Forklifts are utilized to move all chemicals.
• Forklifts are parked in an assigned area when not in use.
Each critical task was broken down into primary and secondary activities. For chemical
transport, the six primary activities are: paperwork associated with chemical transfer, moving
forklift to chemical storage area, locating chemicals in storage area, preparation of chemicals for
transfer, transporting chemicals to MHC process, and transporting chemicals from MHC process
to actual bath. The secondary activities for the primary activity of "transport chemicals to MHC
process" are: move forklift with chemicals, unload line containers, and park forklift in assigned
parking area. For each secondary activity the labor, material, and forklift costs are calculated.
The sum of the costs of a set of secondary activities equals the cost of the primary activity. The
forklift costs are a function of the time that labor and the forklift are used.
For example, for a chemical transport activity that requires two minutes, the labor cost is
$0.34 (based on a labor rate of $10.22 per hour) and the forklift cost is $0.12 (based on $0.06 per
minute). Materials costs are determined for materials other than chemicals and tools required for
an activity. The total of $9.11 in Table 4.20 represents the cost of a single act of transporting
chemicals to the MHC line. The same BOAs are used for all MHC technologies because either
the activities are similar over all MHC technologies or information is unavailable to distinguish
among the technologies. However, individual facilities could modify a BOA to best represent
their unique situations. Table 4.21 presents costs to perform each of the critical tasks one time.
DRAFT
4-36
-------
4.2 COST ANALYSIS
Table 4.20 BO As for Transportation of Chemicals to MHC Line
Activities
A. Paperwork and Maintenance
1 . Request for chemicals
2. Updating inventory logs
3. Safety and environmental record keeping
B. Move Forklift to Chemical Storage Area
1. Move to forklift parking area
2. Prepare forklift to move chemicals
3. Move to line container storage area
4. Prepare forklift to move line container
C Locate Chemicals in Storage Area
1. Move forklift to appropriate areas
2. Move chemical containers from storage to
staging
3. Move containers from staging to storage
D. Preparation of Chemicals for Transfer
1. Open chemical container(s)
2. Utilize correct tools to obtain chemicals
3 Place obtained chemicals in line container(s)
4. Close chemical container(s)
E. Transport Chemicals to Line
1. Move forklift to line
2. Unload line container(s) at line
3. Move forklift to parking area
F. Transport Chemicals from Line to Bath
1. Move line container(s) to bath
2. Clean line container(s)
Time
mid)
2
1
2
2
5
2
3
2
1
2
2
1
3
3
1.5
1
2
1
2
1
2
1
Resources
Labor8
$0.34
$0.17
$0.34
$0.34
$0.85
$0.34
$0.51
$0.34
$0.17
$0.34
$0.34
$0.17
$0.51
$0.51
$0.09
$0.17
$0.34
$0.17
$0.34
$0.17
$0.34
$0.17
Materials11
$0.10
$0.05
$0.10
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.05
$0.05
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.20
$0.00
Forldiftc
$0.00
$0.00
$0.00
$0.12
$0.30
$0.12
$0.18
$0.12
$0.06
$0.12
$0.12
$0.00
$0.00
$0.00
$0.00
$0.06
$0.12
$0.06
$0.12
$0.00
$0.00
$0.00
Total Cost per Transport
Cost
(^/transport)
$0.44
$0.22
$0.44
$0.46
$1.15
$0.46
$0.69
$0.46
$0.23
$0.46
$0.46
$0.22
$0.56
$0.51
$0.09
$0.23
$0.46
$0.23
$0.46
$0.17
$0.54
$0.17
$9.11
Labor rate = $10.22 per hour.
b Materials do not include chemicals or tools
c Forklift operating cost = $0.06 per minute.
4-37
DRAFT
-------
4.2 COST ANALYSIS
Table 4.21 Costs of Critical Tasks
Task
Cost
Transportation of Chemicals
$9.11
Tank Cleanup
$67.00
Bath Setup
$15.10
Sampling and Analysis
$3.70
Filter Replacement
$17.50
Fundamental Principles of Cost Analysis
Previous studies have defined seven principles of a fundamentally sound cost analysis
(DeGamo, et al., 1996), listed below. This analysis was designed to strictly adhere to these
fundamental principles to increase the validity and credibility of the cost formulation.
Principle 1. Develop the alternatives to be considered: Table 4.13 identified the
MHC technologies and equipment configurations considered in the cost analysis. Figure 4.13
listed the generic process steps and typical bath sequences for each of these technologies. These
process steps and bath sequences are used consistently throughout the CTSA.
Principle 2. Focus on the difference between expected future outcomes among
alternatives: Costs that are the same among all technologies do not need to be considered as
there is no difference among alternatives for these costs. However, all costs that differ should be
considered, provided the costs can be reliably estimated. Costs quantified in this analysis are
capital costs, material costs, utility costs, wastewater costs, production costs, and maintenance
costs. These cost categories were summarized earlier in this section and are discussed in more
detail in Section 4.2.3.
Other cost categories are expected to differ in the future outcomes, but cannot be reliably
estimated. These include waste treatment and disposal costs and quality costs. These costs were
considered qualitatively earlier in this section.
Principle 3. Use a consistent viewpoint: The costs to produce a job consisting of
350,000 ssf are estimated for each technology and equipment configuration. Efficient MHC
technologies with the ability to produce the 350,000 ssf quicker are rewarded by having the cost
rates (i.e., $/hr, etc.) of certain costs held constant, but the overall cost is calculated over a
proportionally shorter time period. For example, if labor rates and the number of workers per
day are the same, a process that takes 50 percent less time than the baseline to complete a job
will have 50 percent lower labor costs than the baseline.
Principle 4. Use a common unit of measurement: Costs are normalized to a common
unit of measurement, $/ssf, to compare the relative costs of technologies.
Principle 5. Consider all relevant criteria: A thorough cost analysis requires the
consideration of all criteria relevant to the overall costs of the technologies. The costs considered
DRAFT
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4.2 COST ANALYSIS
in this analysis were defined earlier in this section and are discussed in more detail hi Section
4.2.3.
Principle 6. Make uncertainty explicit: Uncertainty is inherent hi projecting the future
outcomes of the alternatives and should be recognized in the cost analysis. Sensitivity analysis
techniques are utilized to evaluate the effects of critical variables on cost.
Principle 7. Examine the analysis for accuracy: The cost analysis has been peer
reviewed by industry, EPA, and other stakeholders to assess its accuracy and validity.
4.2.2 Simulation Results
Simulation models were run for each of the MHC processes. Three types of simulation
outputs were obtained for use in the cost analysis:
• The duration and frequency of bath replacements.
• The production time required for each process.
• Down time incurred in producing 350,000 ssf.
The baseline process is used below as an example to explain the results of the simulation.
Table 4.22 presents the bath replacement simulation outputs. The values in the table
represent the actual average time for bath replacement for the baseline process. Reviewing the
table reveals that the cleaner/conditioner bath requires replacement nine times. Each replacement
takes an average of 138 minutes. The total replacement time represents the total time the process
is down due to bath replacements. Summing over all baths, bath replacement consumes almost
179 hours (or 10,760) minutes when using the non-conveyorized electroless copper process to
produce 350,000 ssf. Bath replacement simulation outputs for the other MHC processes are
presented in Appendix G.
As shown in the example, the bath replacement output value may be more than or less
than the bath replacement input values reported in Tables 4.17 and 4.18. In this case, the input
value for non-conveyorized electroless copper processes is 180 minutes, but the output values
range from 114 to 230 minutes. Bath maintenance output values are less than input values when,
on average, the bath is shut down with less than 180 minutes remaining hi the shift. Under this
scenario, the simulation model assumes that the employee will stay on past the end of the shift to
complete the bath replacement. Thus, only the time remaining in a normal 8-hour shift is
charged to down time.
Alternately, bath maintenance output values may be greater than input values if more than
180 minutes remain in the shift when the bath is shut down. In this case, the simulation model
assumes that all racks or panels will clear the system prior to shutting down the line for a bath
replacement. Thus, bath replacement times greater than 180 minutes account for the cycle tune
required for racks and/or panels to clear the system.
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4.2 COST ANALYSIS
Table 4.22 Example Simulation Output for Non-Conveyorized Electroless Copper Process:
Frequency and Duration of Bath Replacements
Chemical Bath
Cleaner/Conditioner
Microetch
Predip
Catalyst
Accelerator
Electroless Copper
Acid Dip
Anti-Tarnish
Total
Frequency
9
18
8
1
16
10
6
13
81
Avg. Time/Replacement
(minutes)
138
146
125
230
130
114
146
120
133
Total Time
(minutes)
1,240
2,630
1,000
230
2,080
1,140
876
1,560
10,760
Table 4.23 presents the second and third types of simulation output, the total production
time required for each process, and the down time incurred by each process in producing 350,000
ssf. Total production time is the sum of actual operating time and down time. Down time
includes the 1.2 hours per day the line is assumed inactive plus the time the process is down for
bath replacements. Again, actual simulation outputs are presented in Appendix G.
Table 4.23 Production Time and Down Time for MHC Processes to Produce 350,000 ssf
MHCProcess
Electroless Copper, non-conveyorized (BASELINE)
Electroless Copper, conveyorized
Carbon, conveyorized
Conductive Polymer, conveyorized
Graphite, conveyorized
Non-Formaldehyde Electroless Copper,
non-conveyorized
Organic-Palladium, non-conveyorized
Organic-Palladium, conveyorized
Tin-Palladium, non-conveyorized
Tin Palladium, conveyorized
Total Production Time*
minutes
163,500
36,100
50,800
29,100
33,400
74,600
31,800
45,300
48,500
26,100
days
401
88.4
125
71.3
82.0
183
77.9
111
119
63.9
Total Down Time*
minutes
33,900
16,300
11,800
7,110
6,490
16,400
10,800
18,000
13,600
9,010
days ;
83.2
40.0
28.9
17.4
15.9
40.1
26.4
44.1
33.4
22.1
* To convert from minutes to days, divide by 6.8 hrs per day (408 minutes).
4.2.3 Cost Formulation Details and Sample Calculations
This section develops and describes in detail the cost formulation used for evaluating the
MHC processes. The overall cost was calculated from individual cost categories that are
common to, but expected to vary with, the MHC process alternatives. The cost model was
validated by cross-referencing the cost categories with Tellus Institute (White, et al., 1992), and
Pacific Northwest Pollution Prevention Research Center (Badgett, et al., 1995).
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4.2 COST ANALYSIS
The cost model for an MHC alternative is as follows:
TC= C + M + U + WW + P + MA
where:
TC = total cost to produce 350,000 ssf
C = capital cost
M = material cost
U = utility cost
WW = wastewater cost
P = production cost
MA = maintenance cost
The unit cost of producing 350,000 ssf is then represented as follows:
Unit Cost ($/ssf) = TC ($) / 350,000 ssf
The following sections presents a detailed description of cost calculation methods
together with sample calculations for the baseline non-conveyorized electroless copper process.
Finally, the results of the sample calculations are summarized and then combined to calculate the
total cost and unit cost for the non-conveyorized electroless copper process.
Capital Costs
This section presents methods and sample calculations for calculating capital costs.
Capital costs are one-time or periodic costs incurred in the purchase of equipment or facilities.
In this analysis, capital costs include the costs of primary equipment, equipment installation, and
facility space utilized by the process. Primary equipment is the equipment vital to the operation
of the MHC process without which the process would not be able to operate (i.e., bath tanks,
heaters, rinse water system, etc.). Installation costs include costs to install the process equipment
and prepare it for production. Facility space is the floor space required to operate the MHC
process.
Total capital costs for the MHC technologies were calculated as follows:
C = (E
F)xUR
where:
E = annualized capital cost of equipment ($/yr)
I = annualized capital cost of installation ($/yr)
F = annualized capital cost of facility ($/yr)
UR = utilization ratio
= the time in days required to manufacture 350,000 ssf divided by one operating
year (250 days)
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4.2 COST ANALYSIS
The UR adjusts annualized costs for the amount of time required to process 350,000 ssf,
determined from the simulation models of each process alternative. The components of capital
cost are discussed further below followed by sample calculations of capital costs.
Equipment and Installation Costs. Primary equipment and installation cost estimates
were provided by equipment suppliers and include delivery of equipment and sales tax.
Equipment estimates were based on basic, no frills equipment capable of processing 100
panels/hr. Equipment estimates did not include auxiliary equipment such as statistical process
control or automated sampling equipment sometimes found on MHC process lines.
Annual costs for both the equipment and installation costs were calculated assuming 10-
year, straight-line depreciation of equipment and no salvage value. These annual costs were
calculated using the following equations:
E = equipment cost ($) -*-10 years
I = installation cost ($) •*•10 years
Facility Costs. Facility costs are capital costs for the floor space required to operate the
MHC line. Facility costs were calculated assuming industrial floor space costs $65/ft2 and the
facility is depreciated over 25 years using straight-line depreciation. The cost per square foot of
floor space applies to Class A light manufacturing buildings with basements. This value was
obtained from the Marshall Valuation Service (Vishanoff, 1995) and mean square foot costs
(Ferguson, 1996). Facility costs were calculated using the following equation:
F = [unit cost of facility utilized ($/ft2) x footprint area/process step (fWstep)
x number of steps] •*• 25 years
The "footprint area" is the area of floor space required by MHC equipment, plus a buffer
zone to maneuver equipment or have room to work on the MHC process line.' The footprint area
per process step was calculated by determining the footprint dimensions of each process
alternative, adjusting the dimensions for working space, and then determining the area per
process step. Because the footprint area depends on the type of process automation, the average
dimensions of both conveyorized (5 ft x 38 ft) and non-conveyorized (6 ft x 45 ft) processes were
determined from Workplace Practices Survey data. Since these dimensions account for the
equipment footprint only, an additional 8 ft was added to every dimension to allow space for line
operation, maintenance, and chemical handling. The floor space required by either equipment
type was calculated (1,134 ft2 for conveyorized processes and 1,342 ft2 for non-conveyorized
processes) and used to determine the area required per process step. This was done by first
identifying the process alternative with the fewest process steps for each automation type, and
then dividing the required floor space by that number of steps. This method conservatively
estimated the amount of floor space required per process step for conveyorized processes at 160
1 PWB manufacturers and their suppliers use the term "footprint" to refer to the dimensions of process
equipment, such as the dimensions of the MHC process line.
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4.2 COST ANALYSIS
fWstep and for non-conveyorized processes at 110 ft2/step. The overall area required for each
MHC alternative was then calculated using the following equations:
Conveyorized:
Fc = [$65/ft2 x 160 fWstep x number of steps per process] -5- 25 years
Non-conveyorized:
FN = [$65/ft2 x 110 fWstep x number of steps per process] •*• 25 years
Sample Capital Costs Calculations. This section presents sample capital costs
calculations for the baseline process. From Figure 4.13, the non-conveyorized electroless copper
process consists of 19 chemical bath and rinse steps. Simulation outputs in Table 4.23 indicate
this process takes 401days to manufacture 350,000 ssf of PWB. Equipment vendors estimated
equipment and installation costs at $400,000 and $70,000, respectively (Microplate, 1996;
Coates ASI, 1996; PAL Inc., 1996; Circuit Chemistry, 1996; Western Technology Associates,
1996). The components of capital costs are calculated as follows:
E = $400,000 -10 yrs = $40,000/yr
I = $70,000 - 10 yrs = $7,000/yr
FN = ($65/ft2 x 110 fWstep x 19 steps) - 25 yrs = $5,430/yr
UR = 401days - 250 days/yr = 1.60 yrs
Thus, the capital costs for the non-conveyorized electroless copper process to produce
350,000 ssf of PWB are as follows:
C = ($40,000/yr + $7,000/yr + $5,430/yr) x 1.60 yrs = $83,900
Materials Costs
Materials costs were calculated for the chemical products consumed in MHC process
lines through the initial setup and subsequent replacement of process chemical baths. The
following presents equations for calculating materials costs and sample materials cost
calculations for the baseline process.
Materials Cost Calculation Methods. Chemical suppliers were asked to provide
estimates of chemical costs ($/ssf) early in the project. While some suppliers furnished estimates
for one or more of their process alternatives, several suppliers did not provide chemical cost
estimates for all of their MHC process lines being evaluated. Still others provided incomplete
cost estimates or did not provide any supporting documentation of assumptions used to estimate
chemical costs. Therefore, these data could not be used in the comparative cost estimates.
Instead, chemical costs were estimated using the methods detailed below.
Chemical baths are typically made-up of one or more separate chemical products mixed
together at specific concentrations to form a chemical solution. As PWBs are processed by the
MHC line, the chemical baths become contaminated or depleted and require chemical additions
DRAFT
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4.2 COST ANALYSIS
on replacement. Baths are typically replaced according to analytical results or by supplier
recommended replacement criteria specific to each bath. When the criteria are met or exceeded,
the spent bath is removed and a new bath is created. The chemical cost to replace a specific bath
one time is the sum of the costs of each chemical product in the bath and is given by the
following equation:
Chemical cost/bath replacement = Ej [chemical product cost/bath ($/gal) x % chemical product
hi bath x total volume of bath (gal)]
where:
i
= number of chemical products in a bath
The University of Tennessee Department of Industrial Engineering contacted suppliers to
obtain price quotes in $/gallon or $/lb for MHC chemical products. The compositions of the
individual process baths were determined from Product Data Sheets for each bath. The average
volume of a chemical bath for non-conveyorized processes was calculated to be 75 gallons from
the Workplace Practices Survey data. For conveyorized processes, however, conveyor speed is
constant, thus, the volume of chemicals in a bath varies by bath type to provide the necessary
contact time (see Table 4.16 for conveyorized process bath volumes). These data were used in
the above equation to calculate the chemical cost per bath replacement for each product line. The
bath replacement costs were then averaged across like product lines (i.e., chemical costs from
various suppliers of electroless copper processes were averaged by bath type, etc.) to determine
an average chemical cost per replacement for each process bath.
To obtain the total materials cost, the chemical cost per bath replacement for each bath
was multiplied by the number of bath replacements required (determined by simulation) and then
summed over all the baths in an alternative. The cost of chemical additions was not included
since no data were available to determine the amount and frequency of chemical additions.
Materials costs are given by the following equation:
M = EJ [chemical cost/bath replacement ($) x number of replacements/bath]
where:
= number of baths in a process
The frequency of replacement for individual process baths was determined using supplier
recommended criteria provided on Product Data Sheets and from Workplace Practices Survey
data. Simulation models were used to determine the number of times a bath would be replaced
while an MHC line processes 350,000 ssf of PWB. Appendix G presents bath replacement
criteria used in this analysis and summaries of chemical product cost by supplier and by MHC
technology.
Sample Materials Cost Calculations. Table 4.24 presents an example of chemical costs
per bath replacement for one supplier's electroless copper line. Similar costs are presented in
Appendix G for the six electroless copper chemical product lines evaluated. The chemical costs
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4.2 COST ANALYSIS
per process bath for all six processes were averaged to determine the average chemical cost per
bath for the non-conveyorized electroless copper process.
Table 4.24 Chemical Cost per Bath Replacement for One Supplier of the
Non-Conveyorized Electroless Copper Process
Bath
Cleaner/Conditioner
Microetch
Predip
Catalyst
Accelerator
Electroless Copper
Neutralizer
Anti-Tarnish
Chemical
Product
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
Product
Cost" ($)
$25.45/gal
$2.57/lb
$7.62/gal
$1.60/gal
$1.31/lb
$2.00/gal
$391.80/gal
$1.31/lb
$2.00/gal
$18.10/gal
$27.60/lb
$16.45/gal
$4.50/gal
$1.60/gal
$39.00/gal
Percentage of
Chemical freduet"
6
13.8 g/1
2.5
18.5
31.7 g/1
1.5
4
0.1 7 g/1
3.5
20
7
8.5
0.22
100
0.25
Chemical Cost/Bath
BepIacemeuf^S)
$115
$59
$22
$1,186
$273
$252
$120
$7
a Product cost from supplier of the chemical product.
b The percentage of a chemical product in each process bath was determined from Product Data Sheets provided by
the supplier of the chemical product.
6 Cost per bath calculated assuming bath volumes of 75 gallons.
The chemical cost per bath was then calculated by multiplying the average chemical cost
for a bath by the number of bath replacements required to process 350,000 ssf. The costs for
each bath were then summed to give the total materials cost for the overall non-conveyorized
electroless copper process. Table 4.25 presents the chemical cost per bath replacement, the
number of bath replacements required as determined by simulation, the total chemical cost per
bath, and the total material cost for the non-conveyorized electroless copper process. Similar
material cost calculations for each of the MHC process alternatives are presented in Appendix G.
DRAFT
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43, COST ANALYSIS
Table 4.25 Materials Cost for the Non-Conveyorized Electroless Copper Process
Bath
Cleaner/Conditioner
Microetch
Predip
Catalyst
Accelerator
Electroless Copper
Neutralizer
Anti-Tarnish
Chemical Cost/Bath
Replacement'
$188
$66
$340
$1,320
$718
$317
$120
$16
Number of Bath
Replacements''
9
18
8
1
16
10
6
13
Total ;
Chemical Cost
$1,690
$1,190
$2,720
$1,320
$11,500
$3,170
$720
$208
Total Materials Cost $22,500C
* Reported data represents the chemical cost per bath replacement averaged over six electroless copper product
lines.
b Number of bath replacements required to process 350,000 ssf determined by simulation.
e Does not include cost of chemical additions.
Utility Costs
Utility costs for the MHC process include water consumed by rinse tanks,2 electricity
used to power the panel transportation system, heaters and other process equipment, and natural
gas consumed by drying ovens employed by some MHC alternatives. The utility cost for the
MHC process was determined as follows:
U -W+E+G
where:
W = cost of water consumed ($/ssf) to produce 350,000 ssf
E = cost of electricity consumed ($/ssf) to produce 350,000 ssf
G = cost of natural gas consumed ($/ssf) to produce 350,000 ssf
The following presents utility costs calculation methods and sample utility costs for the
baseline process.
Utility Cost Calculation Methods. The rate of water consumption depends on both the
number of distinct water rinse steps and the flow rate of the water in those steps. The typical
number of water rinse steps for each MHC alternative was determined using supplier provided
data together with data from the Workplace Practices Survey. Cascaded rinse steps were
considered as one rinse step when calculating water consumption since the cascaded rinse steps
all utilize the same water. Ba'sed on Workplace Practices Survey data, the average water flow
rate for individual rinse steps was estimated at 1,185 gals/tank for conveyorized processes and
1,840 gals/tank for non-conveyorized processes. However, it was assumed that the rinse steps
Water is also used in MHC chemical baths to dilute chemical products to the appropriate concentration,
but this use of water was assumed negligible compared to the water consumed in rinse tanks.
DRAFT
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4.2 COST ANALYSIS
are shut off during periods of process down time. Therefore, daily water consumption rates were
adjusted for the percentage of time the process was in operation.
The cost of water was calculated by multiplying the water consumption rate of the MHC
process by the production time required to produce 350,000 ssf of PWB, and then applying a unit
cost factor to the total. Water consumption rates for MHC alternatives are presented in Section
5.1, Resource Conservation, while production times were determined from the simulation
models. A unit cost of $1.60/1000 gallons of water was obtained from the Pollution Prevention
and Control Survey (EPA, 1995a). Following is the equation for calculating water cost:
W = quantity of rinse water consumed (gal) x $ 1.60/1000 gal
The rate of electricity consumption for each MHC alternative depends upon the
equipment required to operate each alternative. Differences in required process equipment such
as the number of heaters, pumps, and type and extent of panel agitation directly affect electricity
consumption. The cost of electricity is calculated by multiplying the electricity consumption rate
of the MHC process by the production time required to produce 350,000 ssf of PWB, and then
applying a unit cost factor to the total. Electricity consumption rates for MHC alternatives are
presented in Section 5.2, Energy Impacts, while the required production time was determined by
simulation. A unit cost of $0.0473/kW-hr was obtained from the International Energy Agency.
Therefore, the energy cost was calculated using the following equation:
E = hourly consumption rate (kW) x required production time (hrs) x
$0.0473/kW-hr
Natural gas is utilized to fire the drying ovens required by both the graphite and carbon
MHC alternatives. The amount of gas consumed was determined by multiplying the natural gas
consumption rate for the MHC process by the amount of operating time required by the process
to produce 350,000 ssf of PWB and then applying a unit cost to the result. Knoxville Utilities
Board (KUB) charges $0.3683 per therm of natural gas consumed (KUB, 1996a). Thus, the cost
of natural gas consumption was calculated by the following equation:
G = natural gas consumption rate (therrn/hr) x required production time (hrs) x
$0.3683/therm
The graphite process typically requires a single drying stage while the carbon process
requires two drying oven stages. Natural gas consumption rates in cubic feet per hour for both
carbon (180 cu.fUhr) and graphite (90 cu.ft./hr) processes were obtained from Section 5.2,
Energy Impacts. The production time required to produce 350,000 ssf of PWB came from
simulation results.
Sample Utility Cost Calculations. The above methodology was used to calculate the
utility costs for each of the MHC alternatives. This section presents sample utility cost
calculations for the non-conveyorized electroless copper process.
DRAFT
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4.2 COST ANALYSIS
Simulation results indicate the non-conveyorized electroless copper process is down 83.2
days and takes 401 days overall (at 6.8 hrs/day) to produce 350,000 ssf. It is comprised of seven
rinse steps which consume approximately 4.1 million gallons of water during the course of the
job (see Section 5.1, Resource Conservation). Electricity is consumed at a rate of 27.2 kW/hr
(see Section 5.2, Energy Impacts). The non-conveyorized electroless copper process has no
drying ovens and, therefore, does not use natural gas. Based on this information, water,
electricity, and gas costs were calculated as follows:
W = 4,089,000 gallons x $ 1.60/1,000 gals = $6,540
E = 27.2 kW x (401 days-83.2 days) x 6.8 hrs/day x $.0473/kW-hr = $2,780
G = $0
Thus, the utility cost for the non-conveyorized electroless copper process was determined
by the calculation:
U = $6,540 + $2,780 + $0 = $9,320
Wastewater Costs
Wastewater Cost Calculation Methods. Wastewater costs for the MHC processes were
only determined for the cost of discharging wastewater to a POTW. The analysis assumes that
discharges are made in compliance with local allowable limits for chemical concentrations and
other parameters so that no fines are incurred.
Wastewater quantities were assumed equal to the quantity of rinse water used. Rinse
water usage was calculated in Section 5.1, Resource Conservation, and used to calculate water
costs hi the Utility Costs section. The unit costs for fees charged by a POTW for both city and
non-city discharges of wastewater were obtained from KUB and averaged for use in calculating
wastewater cost (KUB, 1996b). These average unit costs are not flat rates applied to the total
wastewater discharge, but rather combine to form a tiered cost scale that applies an incremental
unit cost to each level of discharge. The tiered cost scale for wastewater discharges to a POTW
is presented hi Table 4.26.
Table 4.26 Tiered Cost Scale for Monthly Wastewater Discharges to a POTW
Wastewater Discharge
Quantity
(ccf/month)
0-2
3-10
11-100
101-400
401-5,000
City Discharge
Cost
(S/cctfmonth)
$6.30
$2.92
$2.59
$2.22
$1.85
Non-City
Discharge Cost
($/ccf/month)
$7.40
$3.21
$2.85
$2.44
$2.05
Average Discharge ;
Cost
($/Gcf/month)
$6.85
$3.86
$2.72
$2.33
$1.95
Source: KUB, 1996b.
ccf =100 cubic ft.
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4.2 COST ANALYSIS
The unit costs displayed for each level of discharge are applied incrementally to the
quantity of monthly discharge. For example, the first two cubic feet of wastewater discharged in
a month are assessed a charge of $6.85, while the next eight cubic feet cost $3.86, and so on.
The production time required to produce 350,000 ssf of PWB comes from the simulation models.
Thus, wastewater costs were calculated as follows:
WW = Ej [quantity of discharge in tier (ccf/mo) x tier cost factor ($/ccf)] x required
production time (months)
where:
i = number of cost tiers
ccf = 100 cubic ft
Sample Wastewater Cost Calculations. This section presents sample wastewater
calculations for the non-conveyorized electroless copper process. Based on rinse water usage,
the total wastewater release was approximately 4.1 million gallons. The required production
time in months was calculated using the required production time from Table 4.23 and a 250 day
operating year (401 days •*• 250 days/year x 12 months/yr = 19.2 months). Thus, the monthly
wastewater release was 285 ccf (4,089,000 gallons +-19.2 months •*- 748 gal/hundred cu ft). To
calculate the wastewater cost for the non-conveyorized electroless copper process, the tiered cost
scale was applied to the quantity of discharge and the resulting costs per tier were summed, as
follows:
$6.85 x 2 ccf/month = $13.70 ccf/month
$3.86x8ccf/month = $30.88 ccf/month
$2.72 x 90 ccf/month = $245 ccf/month
$2.33 x 185 ccf/month = $431 ccf/month
Monthly discharge cost = $13.70+ $30.88+ $245+ $431 = $721/month
The monthly cost was then multiplied by the number of months required to produce
350,000 ssf of PWB to calculate the overall wastewater treatment cost:
WW = $721/monthx 19.2 month = $13,800
Production Costs
Production Cost Calculation Methods. Production costs for the MHC process include
both the cost of labor required to operate the process and the cost of transporting chemicals to the
production line from storage. Production costs were calculated by the following equation:
= LA + TR
where:
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4.2 COST ANALYSIS
LA = production labor cost ($/ssf) to produce 350,000 ssf
TR = Chemical transportation cost ($/ssf) to produce 350,000 ssf
Production labor cost is a function of the number and type of employees and the length of
time required to complete a job. The calculation of production labor cost assumes that line
operators perform all of the daily activities, excluding bath maintenance, vital to the operation of
the MHC process. Labor costs associated with bath maintenance activities, such as sampling and
analysis, are presented in the discussion of maintenance costs, below. An average number of line
operators was determined for both conveyorized (one line operator) and non-conveyorized (1.1
line operators) processes from Workplace Practices Survey data and supported by site visit
observations. Although no significant difference in the number of line operators by automation
type was reported in the survey, the number of line operators for non-conveyorized processes
was adjusted upward to 1.1 to reflect the greater level of labor content for these processes as
compared to conveyorized processes.
The labor time required to complete the specified job (350,000 ssf) was calculated
assuming an average shift tune of eight hours per day and using the number of days required to
produce 350,000 ssf of PWB from simulation results. A labor wage of $10.22/hr was obtained
from the American Wages and Salary Survey (Fisher, 1995) and utilized for MHC line operators.
Therefore, labor costs for MHC alternatives were calculated as follows:
LA = number of operators x $ 10.22/hr x 8 hrs/day x required production
time (days)
The production cost category of chemical transportation cost includes the cost of
transporting chemicals from storage to the MHC process line. A BOA,, presented in Appendix G,
was developed and used to calculate the unit cost per chemical transport. Since chemicals are
consumed whenever a bath is replaced, the number of trips required to supply the process line
with chemicals equals the number of bath replacements required to produce 350,000 ssf of PWB.
Chemical transportation cost was calculated as follows:
TR = number of bath replacements x unit cost per chemical transport ($)
Sample Production Cost Calculations. For the example of the non-conveyorized
electroless copper process, production labor cost was calculated assuming 1.1 operators working
for 405 days (see Table 4.23). Chemical transportation cost was calculated based on a cost per
chemical transport of $9.1 (see Table 4.20 and Appendix G) and 91 bath replacements (see Table
4.22). Thus, the production cost was calculated as follows:
LA = 1.1 x $10.22 x 8 hrs/day x 401 days = $36,100
TR = Six $9.1 = $737
thus:
= $36,100+ $737 = $36,800
DRAFT
4-50
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4.2 COST ANALYSIS
Maintenance Costs
Maintenance Costs Calculation Methods. The maintenance costs for the MHC process
include the costs associated with tank cleaning, bath setup, sampling and analysis of bath
chemistries, and bath filter replacement. Maintenance costs were calculated as follows:
MA =TC + BS + FR+ST
where:
TC = tank cleanup cost ($/ssf) to produce 350,000 ssf
BS = bath setup cost ($/ssf) to produce 350,000 ssf
FR = filter replacement cost ($/ssf) to produce 350,000 ssf
ST = sampling cost ($/ssf) to produce 350,000 ssf
The maintenance costs listed above depend on the unit cost per repetition of the activity l
and the number of times the activity was performed. For each maintenance cost category, a BOA:
was developed to characterize the cost of labor, materials, and tools associated with a single
repetition of that activity. The BOA and unit cost per repetition for each cost category are . ,
presented in Appendix G. It was assumed that the activities and costs characterized on the BO As,
are the same regardless of the MHC process or process baths. Unit costs per repetition for both
tank cleanup and bath setup were determined to be $67.00 and $15.10, respectively.
The number of tank cleanups and bath setups equals the number of bath replacements
obtained from process simulation results (see Appendix G). Each time a bath is replaced, the
tank is cleaned before a replacement bath is created. The costs of tank cleanup and bath setup are
thus given by the following:
TC = number of tank cleanups x $67.00
BS = number of bath setups x$ 15.10
Workplace Practices Survey data for both filter replacement and bath sampling and
analysis were reported in occurrences per year instead of as a function of throughput. Ninetieth
percentile values were calculated from these data and used in dermal exposure estimates in
Section 3.2, Exposure Assessment. These frequencies were adjusted for this analysis using the
URs for the production time required to manufacture 350,000 ssf of PWB. Using the unit costs
determined by the BOAs developed for filter replacement ($17.50 per replacement) and bath
sampling and testing ($3.70 per test), the costs for these maintenance activities were calculated as
follows:
FR = annual number of filter replacement xURx$ 17.50
ST = annual number of sampling & testing x UR x $3.70
The total maintenance cost for each MHC process alternative was determined by first
calculating the individual maintenance costs using the above equations and then summing the
results.
DRAFT
4-51
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4.2 COST ANALYSIS
Maintenance Costs Sample Calculations. This section presents sample maintenance
costs calculations for the non-conveyorized electroless copper process. From Table 4.23, this
process has a production time of 401 days, which gives a UR of 1.60 (UR = 401 •*- 250). The
number of tank cleanups and bath setups equals the number of bath replacements reported in
Table 4.22 (81 bath replacements). As reported in Section 3.2, Exposure Assessment, chemical
baths are sampled and tested 720 per year and filters are replaced 100 times per year. Thus, the
maintenance costs for the non-conveyorized electroless copper process are:
TC = 81 x $67.00 = $5,430
BS = Six $15.10 = $1,220
ST = 720 x 1.60 x $3.70 = $4,260
FR = 100 x 1.60 x 17.50 = $2,800
therefore:
MA = $5,430+ $1,220+ $4,320+ $2,830 = $13,800
Determination Total Cost and Unit Cost
The total cost for MHC process alternatives was calculated by summing the totals of the
individual costs categories. The unit cost (UC), or cost per ssf of PWB produced, can then be
calculated by dividing the total cost by the amount of PWBs produced. Table 4.27 summarizes
the total cost of manufacturing 350,000 ssf of PWB using the non-conveyorized electroless
copper process.
The UC for the non-conveyorized electroless copper process was then calculated as
follows:
UC = total cost (TC) •*• 350,000 ssf
= $180,000-350,000 ssf
= $0.51/ssf
DRAFT
4-52
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4.2 COST ANALYSIS
Table 4.27 Summary of Costs for the Non-Conveyorized Electroless Copper Process
Cost Category
Capital Cost
Utility Cost
Production Cost
Maintenance Cost
Total Cost
Component
Primary Equipment
Installation
Facility
Water
Electricity
Natural Gas
Wastewater Discharge
Transportation of Material
Labor for Line Operation
Tank Cleanup
Bath Setup
Sampling and Analysis
Filter Replacement
Component Cost
$64,000
$11,200
$8,690
$22,500
$6,540
$2,780
$0
Totals ;
$83,900
$22,500
$9,320
$13,8001 $13,800
$737
$36,100
$5,430
$1,220
$4,260
$2,800
$36,800
$13,800
$180,000
4.2.4 Results
Table 4.28 presents the costs for each of the MHC technologies. Table 4.29 presents unit
costs ($/ssf). The total cost of producing 350,000 ssfranged from a high of $180,000 for the
non-conveyorized electroless copper process to a low of $33,500 for the conveyorized
conductive polymer process. Corresponding unit costs ranged from $0.51/ssf for the baseline
process to $0.09/ssf for the conveyorized conductive polymer process. With the exception of the
non-conveyorized, non-formaldehyde electroless copper process, all of the alternatives cost at
least 50 percent less than the baseline. Both conveyorized and non-conveyorized equipment
configurations were costed for the electroless copper, tin-palladium, and organic-palladium MHC
alternatives. For the electroless copper technology, the conveyorized process was much more
economical than the non-conveyorized process. Less difference in unit cost was seen between
the tin-palladium technologies ($0.12/ssf for conveyorized processes and $0.14/ssf for non-
conveyorized processes) and the organic palladium technologies ($0.17/ssf for conveyorized
processes and $0.15/ssf for non-conveyorized processes). Non-conveyorized processes are, on
average, more expensive ($0.30) than conveyorized systems ($0.16).
Total cost data in Table 4.28 illustrate that chemical cost is typically the largest cost (in
nine out often MHC processes) followed by equipment cost (in one out often MHC processes).
The high costs of the baseline process appear to be primarily due to the length of time it took this
process to produce 350,000 ssf (4015 days). This is over twice as long as that required by the
next process (183 days for non-conveyorized, non-formaldehyde electroless copper).
DRAFT
4-53
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4.2 COST ANALYSIS
Table 4.28 Total Cost of MHC Alternatives
Cost Category
Capital Cost
Utility Cost
Wastewater Cost
Production
Cost
Maintenance
Cost
Cost Components
Primary Equipment
Installation
Facility
Chemical(s)
Water
Electricity
Natural Gas
Wastewater Discharge
Transportation of Material
Labor for Normal Production
Tank Cleanup
Bath Setup
Sampling and Testing
Filter Replacement
Total Cost
Electroless Copper,
Bon<-conveyorlzed
$64,000
$11,200
$8,690
$22,500
$6,540
$2,780
$0
$13,800
$737
$36,100
$5,430
$1,220
$4,260
$2,800
$180,000
Carbon,
conveyorized
$7,470
$299
$2,690
$32,900
$725
$836
$418
$1,750
$446
$10,200
$3,280
$740
$405
$116
862,300
Conductive
Polymer*
conveyorized :
$5,560
$0
$2,250
$10,400
$410
$460
$0
$987
$673
$5,830
$4,960
$1,120
$436
$376
$33,500
Cost Category
Capital Cost
Material Cost
Utility Cost
Wastewater Cost
Production
Cost
Maintenance
Cost
Cost Components
Primary Equipment
Installation
Facility
Chemical(s)
Water
Electricity
Natural Gas
Wastewater Discharge
Transportation of Material
Labor for Normal Production
Tank Cleanup
Bath Setup
Sampling and Testing
Filter Replacement
Total Cost
Electroless
Copper*
conveyorized
$6,190
$212
$2,800
$22,600
$642
$669
$0
$1,480
$883
$7,230
$6,500
$1,460
$942
$612
852,200
Graphite,
conveyorized
$3,580
$131
$1,090
$59,800
$251
$462
$145
$637
$319
$6,700
$2,350
$529
$316
$901
$77,200
Non-Formaldehyde
Electroless Copper,
non-eonveyorized
$29,300
$5,120
$3,350
$69,600
$2,100
$1,310
$0
$4,580
$682
$16,200
$5,030
$1,130
$691
$214
8139,300
DRAFT
4-54
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4.2 COST ANALYSIS
Table 4.28 Total Cost of MHC Alternatives (cont.)
Cost Category
Capital Cost
Material Cost
Utility Cost
Wastewater Cost
Production Cost
Maintenance
Cost
Cost Components \
Primary Equipment
Installation
Facility
Chemical(s)
Water
Electricity
Natural Gas
Wastewater Discharge
Transportation of Material
Labor for Normal Production
Tank Cleanup
Bath Setup
Sampling and Testing
Filter Replacement
Total Cost
Organic-Palladium,
eonveyorized
$5,780
$356
$2,220
$28,900
$635
$720
$0
$1,540
$1,260
$6,530
$9,250
$2,080
$411
$271
$60,000
Organic-Palladium,
aon~eonveyorized
$4,160
$256
$1,100
$27,000
$758
$325
$0
$1,690
$1,050
$7,190
$7,710
$1,740
$288
$385
$53,700
Cost Category
Capital Cost
Material Cost
Utility Cost
Wastewater Cost
Production
Cost
Maintenance
Cost
Cost Components
Primary Equipment
Installation
Facility
Chemical(s)
Water
Electricity
Natural Gas
Wastewater Discharge
Transportation of Material
Labor for Normal Production
Tank Cleanup
Bath Setup
Sampling and Testing
Filter Replacement
Total Cost
Tin-Palladium,
conveyorized
$1,280
$205
$1,490
$22,500
$317
$468
$0
$774
$537
$5,230
$3,950
$891
$493
$332
$41,500
Tin-Palladium,
non-eonveyorized
$4,760
$381
$1,910
$22,300
$1,010
$635
$0
$2,380
$455
$10,700
$3,350
$755
$916
$616
$50,200
4-55
DRAFT
-------
4.2 COST ANALYSIS
Table 4.29 MHC Alternative Unit Costs
MHC Alternative
Electroless Copper, non-conveyorized (BASELINE)
Carbon, conveyorized
Conductive Polymer, conveyorized
Electroless Copper, conveyorized
Graphite, conveyorized
Non-Formaldehyde Electroless Copper, non-conveyorized
Organic-Palladium, conveyorized
Organic-Palladium, non-conveyorized
Tin-Palladium, conveyorized
Tin-Palladium, non-conveyorized
Production
(s$#yjr)
350,000
350,000
350,000
350,000
350,000
350,000
350,000
350,000
350,000
350,000
Total Cost
($)
$180,000
$62,300
$33,500
$52,200
$77,200
$139,300
$60,000
$53,700
$41,500
$41,900
UttitCosl
(&M> !
$0.51
$0.18
$0.09
$0.15
$0.22
$0.40
$0.17
$0.15
$0.12
$0.14
4.2.5 Sensitivity Analysis
This section presents the results of sensitivity analyses to determine the effects of critical
variables on overall costs. Three separate sensitivity analyses were performed, including
sensitivity analyses to determine the following:
• The effects of the various cost components on the overall cost of the alternatives.
• The effects of down time on the cost of the baseline process.
• The effects of water consumption on the cost of the baseline process.
To determine the effects of the various cost components on overall cost, each cost
component was increased and decreased by 25 percent, 50 percent, and 75 percent, and an overeill
cost was calculated. Figure 4.15 presents the results of this sensitivity analysis for the baseline
process. Appendix G presents the results of this type of sensitivity analysis for the alternatives.
The results indicate two groupings of cost components: 1) those that have little impact on the
overall cost; and 2) those which have significant impact on the overall cost of an MHC
alternative. The first category includes tank cleanup, electricity, filter replacement, sampling and
analysis, bath setup, transportation, and natural gas costs. The second category includes
equipment, labor, and chemical costs.
To determine the effects of down time on the overall cost of the baseline process, the
duration of bath replacements was reduced by 33 percent and 67 percent. Both the 33 and 67
percent reductions led to a less than one percent reduction hi overall cost. These results indicate
the effects of down time on overall costs are small.
DRAFT
4-56
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4.2 COST ANALYSIS
O]
-------
4.2 COST ANALYSIS
Water consumption was also reduced by 33 percent and 67 percent to determine its
effects on the overall cost of the baseline process. Reducing water consumption affects both
water costs and wastewater discharge costs. Reducing water consumption by 33 percent resulted
in an overall cost reduction of 2.8 percent, while reducing water consumption by 67 percent
reduced the overall cost by 5.9 percent.
4.2.6 Conclusions
This analysis developed comparative costs for seven MHC technologies, including
electroless copper, conductive polymer, carbon, graphite, non-formaldehyde electroless copper,
organic-palladium, and tin-palladium processes. Costs were developed for each technology and
equipment configuration for which data were available from the Workplace Practices Survey and
Performance Demonstration, for a total often processes (four non-conveyorized processes and
six conveyorized processes.) Costs were estimated using a hybrid cost model which combines
traditional costs with simulation modeling and activity-based costs. The cost model was
designed to determine the total cost of processing a specific amount of PWBs through a fully
operational MHC line, in this case 350,000 ssf. The cost model does not estimate start-up costs
for a facility swtiching to an MHC alternative. Total costs were divided by the throughput
(350,000 ssf) to determine a unit cost in $/ssf.
The cost components considered include capital costs (primary equipment, installation,
and facility costs), materials costs (limited to chemical costs), utility costs (water, electricity, and
natural gas costs), wastewater costs (limited to wastewater discharge cost), production costs
(production labor and chemical transport costs), and maintenance costs (tank cleanup, bath setup.,
sampling and analysis, and filter replacement costs). Other cost components may contribute
significantly to overall costs, but were not quantified because they could not be reliably
estimated. These include wastewater treatment cost, sludge recycling and disposal cost, other
solid waste disposal costs, and quality costs.
Based on the results of this analysis, all of the alternatives are more economical than the
non-conveyorized electroless copper process. In general, conveyorized processes cost less than
non-conveyorized processes. Costs ranged from $0.51/ssf for the baseline process to $0.09/ssf
for the conveyorized conductive polymer process. Seven process alternatives cost less than
$0.20/ssf (conveyorized carbon at $0.18/ssf, conveyorized conductive polymer at $0.09/ssf,
conveyorized electroless copper at $0.15/ssf, non-conveyorized organic palladium at $0.15/ssf,
conveyorized organic-palladium at $0.17/ssf, and conveyorized and non-conveyorized tin-
palladium at $0.12/ssf and $0.14/ssf, respectively). Three processes cost more than $0.20/ssf
(non-conveyorized electroless copper at $0.51/ssf, non-conveyorized non-formaldehyde
electroless copper at $0.40/ssf, and conveyorized graphite at $0.22/ssf).
Chemical cost was the single largest component cost for nine of the ten processes.
Equipment cost was the largest cost for one process. Three separate sensitivity analyses of the
results indicated that chemical cost, production labor cost, and equipment cost have the greatest
effect on the overall cost results.
DRAFT
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4.3 REGULATORY STATUS
4.3 REGULATORY STATUS
This section of the CTSA describes the federal environmental regulations that may affect
the chemicals in the MHC technologies. Discharges of these chemicals may be restricted by air,
water, or solid waste regulations, and releases may be reportable under the federal Toxic Release
Inventory (TRI) program. This section discusses pertinent portions of the Clean Water Act
(Section 4.3.1), the Safe Drinking Water Act (Section 4.3.2), the Clean Air Act (Section 4.3.3),
the Resources Conservation and Recovery Act (Section 4.3.4), the Comprehensive
Environmental Response, Compensation and Liability Act (Section 4.3.5), the Superfund
Amendments and Reauthorization Act and Emergency Planning and Community Right-to-Know
Act (Section 4.3.6), and the Toxic Substances Control Act (Section 4.3.7). In addition, it
summarizes pertinent portions of the Occupational Safety and Health Act (Section 4.3.8).
Section 4.3.9 summarizes the federal environmental regulations by MHC technology. This
information is intended to provide an overview of environmental regulations potentially triggered
by MHC chemicals. It is not intended to be used as regulatory guidance.
The primary sources of information for this section were the EPA Register of Lists (EPA,
1996) and the EPA document, Federal Environmental Regulations Affecting the Electronics
Industry (EPA, 1995b). This is a database of federal regulations applicable to specific chemicals
that can be searched by chemical. The latter was prepared by the DfE PWB Project. Of the 62
chemicals used in one or more of the MHC technologies, no regulatory listings were found for 21
chemicals.
4.3.1 Clean Water Act
The Clean Water Act (CWA) is the basic federal law governing water pollution control in
the U.S. today. The various MHC processes used by the PWB industry contain a number of
chemicals that are regulated under the CWA. Applicable provisions, as related to specific
chemicals found in MHC technologies, are presented in Table 4.30; these particular provisions
and process-based regulations are discussed in greater detail below.
CWA Hazardous Substances and Reportable Quantities
The CWA designates hazardous substances under Section 31 l(b)(2)(a) which, when
discharged to navigable waters or adjoining shorelines, present an imminent and substantial
danger to the public health or welfare, including fish, shellfish, wildlife, shorelines, and beaches.
40 Code of Federal Regulations (CFR) Part 117 establishes the Reportable Quantity (RQ) for
each substance listed in 40 CFR Part 116. When an amount equal to or in excess of the RQ is
discharged, the facility must provide notice to the federal government of the discharge, following
Department of Transportation requirements set forth hi 33 CFR Section 153.203. Liability for
cleanup can result from such discharges. This requirement does not apply to facilities that
discharge the substance under a National Pollutant Discharge Elimination System (NPDES)
Permit or a CWA Section 404 dredge and fill permit, or to a Publicly-Owned Treatment Works
(POTW), as long as any applicable effluent limitations or pretreatment standards have been met.
DRAFT
4-59
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4.3 REGULATORY STATUS
Table 4.30 lists RQs of hazardous substances under the CWA that may apply to chemicals used
in the MHC process.
Table 4.30 CWA Regulations That May Apply to Chemicals in MHC Technologies
Chemical
Ammonia
Ammonium Chloride
Copper (I) Chloride; Copper
Copper Sulfate
Ethylenediaminetetraacetic Acid (EDTA)
Formaldehyde
Formic Acid
Hydrochloric Acid
Isophorone
Phosphoric Acid
Potassium Cyanide
Potassium Hydroxide
Silver
Sodium Bisulfate
Sodium Cyanide
Sodium Hydroxide
Sulfuric Acid
CWA 311 RQ
(Ibs.)
100
5,000
10
10
5,000
100
5,000
5,000
5,000
10
1,000
5,000
10
1,000
1,000
CWA Priority
Pollutant
/
/
/
/
/
/
CWA307a
/
/
/
/
/
/
CWA304b
/
/
/
/
S
Abbreviations and definitions:
CWA - Clean Water Act
CWA 304b - Effluent Limitations Guidelines
CWA 307a - Toxic Pollutants
CWA 311 - Hazardous Substances
RQ - Reportable Quantities of CWA 311 hazardous
substances
The NPDES permit program (40 CFR Part 122) contains regulations governing the
discharge of pollutants to waters of the U.S. Forty states and one territory are authorized to
administer NPDES programs that are at least as stringent as the federal program; EPA
administers the program in states that are not authorized to do so. The following discussion
covers federal NPDES requirements. Facilities may be required to comply with additional state
requirements not covered hi this document.
The NPDES program requires permits for the discharge of "pollutants" from any "point
source" into "navigable waters" (except those covered by Section 404 dredge and fill permits).
CWA defines all of these terms broadly, and a source is required to obtain an NPDES permit if it
discharges almost anything other than dredge and fill material directly to surface waters. A
source that sends its wastewater to a POTW is not required to obtain an NPDES permit, but may
be required to obtain an industrial user permit from the POTW to cover its discharge.
DRAFT
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4.3 REGULATORY STATUS
CWA Priority Pollutants
In addition to other NPDES permit application requirements, facilities will need to be
aware of priority pollutants listed in 40 CFR Part 122, Appendix D; this list of 126 compounds
was developed by EPA to define a specific list of chemicals to be given priority consideration in
the development of effluent limitations. Each applicant for an NPDES permit must provide
quantitative data for those priority pollutants which the applicant knows or has reason to believe
will be discharged in greater than trace amounts. Each applicant must also indicate whether it
knows or has reason to believe it discharges any of the other hazardous substances or non-
conventional pollutants listed at 40 CFR Part 122, Appendix D. Quantitative testing is not
required for the other hazardous pollutants; however, the applicant must describe why it expects
the pollutant to be discharged and provide the results of any quantitative data about its discharge
for that pollutant. Quantitative testing is required for the non-conventional pollutants if the
applicant expects them to be present in its discharge.
CWA Effluent Limitations Guidelines
A principal means for attaining water quality objectives under the CWA is the
establishment and enforcement of technology-based effluent limitations, which are based on the
pollutant control capabilities of available technologies, taking into consideration the economic
achievability of these limitations and a number of other factors. Because of differences in
production processes, quantities, and composition of discharges, separate standards are
established for discharges associated with different industry categories. These standards are
referred to as technology-based effluent limitation guidelines.
The effluent limitation to be applied to a particular pollutant in a particular case depends
on the following:
• Whether the pollutant is conventional, nonconventional, or toxic.
• Whether the point source is a new or existing source.
• Whether the point source discharges directly to the waters of the U.S. or to a POTW.
(Facilities that discharge to POTWs must comply with the pretreatment standards.)
Existing sources must comply with either best practicable control technology currently
available (BPT), best conventional pollution control technology (BCT), or best available control
technology economically practicable (BAT) standards. New facilities must comply with New
Source Performance Standards. NPDES permits must also contain any more stringent permit
limitations based on state water quality standards.
In the absence of effluent limitation guidelines for a facility category, permit writers
establish technology-based controls using their Best Professional Judgement. In essence, the
permit writer undertakes an effluent guideline-type analysis for a single facility. The permit
writer will use information such as permit limits from similar facilities using similar treatment
technology, performance data from actual operating facilities, and scientific literature. Best
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4.3 REGULATORY STATUS
Professional Judgement may not be used in lieu of existing effluent guidelines. These guidelines
apply only to direct dischargers of wastewater.
Pretreatment Standards
Only those facilities that discharge pollutants into waters of the U.S. need to obtain an
NPDES permit. Facilities that discharge to POTWs, however, must comply with pretreatment
requirements, as set out in Section 307 of CWA. These requirements were developed because of
concern that dischargers' waste containing toxic, hazardous, or concentrated conventional
industrial wastes might "pass through" POTWs or that pollutants might interfere with the
successful operation of the POTW.
40 CFR Part 413 contains pretreatment standards for existing sources. Existing sources
are those which, since July 15,1983, have not commenced construction of any building or
facility that might result in a discharge. For the MHC step of the PWB manufacturing process,
the main pollutant of concern is copper and copper compounds. Table 4.31 describes PWB
pretreatment standards applicable to copper.
Table 4.31 PWB Pretreatment Standards Applicable to Copper
,
Facilities discharging 38,000 liters or more per
day - Existing Sources
Facilities discharging 38,000 liters or more per
day - Existing Sources
All plants except job shops and independent PWB
manufacturers - Existing Sources (metal finishing)11
New Sources6 Limitations (metal finishing)
Maximum for
Iday
(mg/l)
4.5
401"
3.38
3.38
Average Daily Value for
4 Consecutive Days
(rogrt)
2.7
241"
2.07
2.07
preceding category under prior agreement between a source subject to these standards and the POTW receiving such
regulated wastes.
b "Metal finishing" applies to plants performing any of the following operations on any basis material:
electroplating, electroless plating, anodizing, coating, chemical etching and milling and PWB manufacturing.
Pretreatment standards have been promulgated for Total Toxic Organics (TTO) in this category; none of the
chemicals evaluated in the MHC technologies are listed.
" Pretreatment standards for new sources applies to facilities that commenced construction after July 15,1983.
4.3.2 Safe Drinking Water Act
The Federal Safe Drinking Water Act (SDWA) was first passed in 1974; it has been
amended several times. The purpose of the SDWA is to make sure the drinking water supplied
to the public is safe and wholesome. It requires water monitoring and limitations on the presence
of chemical contaminants, viruses, and other disease-causing organisms in public water systems
that serve 25 or more people. The SDWA also includes provisions for protection of groundwater
resources hi areas around wells that supply public drinking water. In addition, the injection of
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4.3 REGULATORY STATUS
wastes into deep wells that are above or below drinking water sources are regulated by the
SDWA Underground Injection Program (40 CFR Part 144). While most of the regulations under
the SWDA affect public water supplies and suppliers, PWB manufacturers could be affected by
the groundwater protection policies or the regulation of underground injection wells.
. National Primary and Secondary Drinking Water Regulations
The SDWA National Primary Drinking Water Regulations (NPDWR) (40 CFR Part 141)
set maximum concentrations for substances found in drinking water that may have an adverse
affect on human health. The National Secondary Drinking Water Regulations (NSDWR)(40
CFR Part 143) established guidelines for contaminants hi drinking water that primarily affect the
aesthetic qualities related to public acceptance of drinking water. The NSDWR are not federally
enforceable but are intended as guidelines for the states. Table 4.32 presents MHC chemicals
listed by these provisions of the SDWA.
Table 4.32 SWDA Regulations That May Apply to Chemicals in MHC Technologies
Chemical
Copper (I) Chloride; Copper
Copper Sulfate
Fluoroboric Acid (as fluoride)
Silver
SWBAKPDWR
/
/
/
SWBANSBWM
S
/
/
/
Abbreviations and definitions:
SDWA - Safe Drinking Water Act
SDWA NPDWR - National Primary Drinking Water Rules
SDWA NSDWR - National Secondary Drinking Water Rules
4.3.3 Clean Air Act
The Clean Air Act (CAA), with its 1990 amendments, sets the framework for air
pollution control in the U.S. The various MHC technologies produce a number of pollutants that
are regulated under the CAA. Applicable provisions, as related to specific chemicals, are
presented in Table 4.33; these particular provisions and process-based regulations are discussed
below.
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Table 4.33 CAA Regulations That May Apply to Chemicals in MHC Technologies
Chemical
2-Ethoxyethanol
1,3-BenezenedioI
2^Butoxyethanol Acetate; Butylcellusolve Acetate
Ammonia
Diethylene Glycol Ethyl Ether
Diethylene Glycol Methyl Ether
Dimethylformamide
Ethylene Glycol
Fluoroboric Acid (as fluoride)
Formaldehyde
Formic Acid
Hydrochloric Acid
Isophorone
Methanol
p-Toluene Sulfonic Acid
Potassium Cyanide
Sodium Cyanide
Sulfuric Acid
CAA 111
^
/
/
/
/
/
/
/
/
/
/
S
/
/
CAA112&
Hazardous Air Pollutants
/
/
/
/
/
/
/
S
/
/
CAA 112r
/
/
^
Abbreviations and definitions:
CAA - Clean Air Act
CAA 111 - Standards of Performance for New Stationary Sources of Air Pollutants-Equipment Leaks Chemical List
CAA 112b - Hazardous Air Pollutant
CAA 112r - Risk Management Program
Hazardous Air Pollutants
Section 112 of the CAA established a program of regulation development for 189
hazardous air pollutants and directed EPA to add other compounds to the list as needed. EPA is
authorized to establish Maximum Achievable Control Technology (MACT) standards for source
categories that emit at least one of the pollutants on the list. Chemicals listed in Section 112(b)
of the CAA that are used in PWB manufacturing are shown in Table 4.33. EPA is in the process
of identifying categories of industrial facilities that emit substantial quantities of any of these 189
pollutants and will develop emissions limits for those industry categories.
Section 112(r) of the CAA deals with sudden releases of or accidents involving acutely
toxic, explosive, or flammable chemicals. This provision, added by the CAA Amendments of
1990, establishes a list of substances which, if present in a process in a quantity hi excess of a
threshold, would require that the facility establish a Risk Management Program to prevent
chemical accidents. This program would include preparing a risk management plan for
submission to the state and to local emergency planning organizations.
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Minimum Standards for State Operating Permit Programs
The CAA and its implementing regulations (at 40 CFR Part 70) define the minimum
standards and procedures required for state operating permit programs. The permit system is a
new approach established by the 1990 Amendments that is designed to define each source's
requirements and to facilitate enforcement. In addition, permit fees will generate revenue to fund
implementation of the program.
Any facility defined as a "major source" is required to secure a permit. Section 70.2 of
the regulations defines a source as a single point from which emissions are released or as an
entire industrial facility that is under the control of the same person(s). A major source is defined
as any source that emits or has the potential to emit:
• 10 tons per year (TPY) or more of any hazardous air pollutant.
• 25 TPY or more of any combination of hazardous air pollutants.
• 100 TPY of any air pollutant.
For ozone non-attainment areas, major sources are defined as sources with the potential to
emit:
• 100 TPY or more of volatile organic compounds (VOCs) in areas defined as marginal or
moderate.
• 50 TPY or more of VOCs in areas classified as serious.
• 25 TPY or more of VOCs in areas classified as severe.
• 10 TPY or more of VOCs in areas classified as extreme.
In addition to major sources, all sources that are required to undergo New Source Review,
are subject to New Source Performance Standards, or are identified by federal or state
regulations, must obtain a permit.
By November 15,1993, each state must submit a design for an operating permit program
to EPA for approval. EPA must either approve or disapprove the state's program within one year
after submission. Once approved, the state program goes into effect.
Major sources, as well as the other sources identified above, must submit their permit
applications to the state within one year of approval of the state program. (This was scheduled to
take place near the end of 1995.) Once a source submits an application, it may continue to
operate until the permit is issued. Permit issuance may take years because permit processing
allows time for terms and conditions to be presented to and reviewed by the public and
neighboring states as well as by EPA. Applicants should make certain that their applications
contain a comprehensive declaration of all allowable emissions, because current emissions are
used as the basis for calculating proposed reductions to meet future limits.
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When issued, the permit will include all air requirements applicable to the facility.
Among these are compliance schedules, emissions monitoring, emergency provisions, self-
reporting responsibilities, and emissions limitations. Five years is the maximum permit term.
As established hi 40 CFR Part 70, the states are required to develop fee schedules to
ensure the collection and retention of revenues sufficient to cover permit program costs. The
CAA sets a presumptive minimum annual fee of $25 per ton for all regulated pollutants (except
carbon monoxide), but states can set higher or lower fees so long as they collect sufficient
revenues to cover program costs.
4.3.4 Resource Conservation and Recovery Act
One purpose of the Resource Conservation and Recovery Act (RCRA) of 1976 (as
amended in 1984) is to set up a cradle-to-grave system for tracking and regulating hazardous
waste. EPA has issued regulations, found in 40 CFR Parts 260-299, which implement the federal
statute. These regulations are Federal requirements. As of March 1994,46 states have been
authorized to implement the RCRA program and may include more stringent requirements in
their authorized RCRA programs. In addition, non-RCRA-authorized States (Alaska, Hawaii,
Iowa, and Wyoming) may have state laws that set out hazardous waste management
requirements. A facility should always check with the state when analyzing which requirements
apply to their activities.
To be a hazardous waste, a material must first be a solid waste, which is defined broadly
under RCRA and RCRA regulations. Assuming the material is a solid waste, the first evaluation
to be made is whether it is also considered a hazardous waste. 40 CFR Part 261 addresses the
identification and listing of hazardous waste. The waste generator has the responsibility for
determining whether a waste is hazardous, and what classification, if any, may apply to the
waste. The generator must examine the regulations and undertake any tests necessary to
determine if the wastes generated are hazardous. Waste generators may also use their own
knowledge and familiarity with the waste to determine whether it is hazardous. Generators may
be subject to enforcement penalties for improperly determining that a waste is not hazardous.
RCRA Hazardous Waste Codes
Wastes can be classified as hazardous either because they are listed by EPA through
regulation in 40 CFR Part 261 or because they exhibit certain characteristics: tOxicity,
corrosivity, reactivity, or ignitability. Listed hazardous wastes are specifically named (e.g.,
discarded commercial toluene, spent non-halogenated solvents). Characteristic hazardous wastes
are solid waste which "fail" a characteristic test, such as the RCRA test for ignitability.
There are four separate lists of hazardous wastes in 40 CFR Part 261. If any waste from a
PWB facility is on any of these lists, the facility is subject to regulation under RCRA. The
listing is often defined by industrial processes, but all wastes are listed because they contain
particular chemical constituents (these constituents are listed in Appendix VII to Part 261).
Section 261.31 lists wastes from non-specific sources and includes wastes generated by industrial
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processes that may occur in several different industries; the codes for such wastes always begin
with the letter "F." The second category of listed wastes (40 CFR Section 261.32) includes
hazardous wastes from specific sources; these wastes have codes that begin with the letter "K."
The remaining lists (40 CFR Section 261.33) cover commercial chemical products that have been
or are intended to be discarded; these have two letter designations, "P" and "U." Waste codes
beginning with "P" are considered acutely hazardous, while those beginning with "U" are simply
considered hazardous. Listed wastes from chemicals that are used in an MHC process are shown
in Table 4.34. While this table is intended to be as comprehensive as possible, individual
facilities may use other chemicals and generate other listed hazardous wastes that are not
included in Table 4.34. Facilities may wish to consult the lists at 40 CFR 261.31-261.33.3
Table 4.34 RCRA Hazardous Waste Codes That May Apply to Chemical Wastes From
MHC Technologies
Chemical
2-Ethoxyethanol
1,3 Benezenediol
Formaldehyde
Formic Acid
Methanol
Potassium Cyanide
Sodium Cyanide
II Waste Code
U359
U201
U122
U123
U154
F Waste Code
P098
P106
Generator Status
The hazardous waste generator is defined as any person, by site, who creates a hazardous
waste or makes a waste subject to RCRA Subtitle C. Generators are divided into three
categories:
• Large Quantity Generators (LQG) - These facilities generate at least 1,000 kg
(approximately 2,200 Ibs) of hazardous waste per month, or greater than 1 kg (2.2 Ibs) of
acutely hazardous waste per month.
• Small Quantity Generators (SQG) - These facilities generate greater than 100 kg
(approximately 220 Ibs) but less than 1,000 kg of hazardous waste per month, and up to 1
kg (2.2 Ibs) per month of acutely hazardous waste.
• Conditionally Exempt Small Quantity Generators (CESQG) - These facilities generate no
more than 100 kg (approximately 220 Ibs) per month of hazardous waste and up to 1 kg
(2.2 Ibs) per month of acutely hazardous waste.
Large and small quantity generators must meet many similar requirements. 40 CFR Part
262 provides that SQGs may accumulate up to 6,000 kg of hazardous waste on-site at any one
time for up to 180 days without being regulated as a treatment, storage, or disposal facility
Lists of the "F, P, K and U" hazardous wastes can also be obtained by calling the EPA
RCRA/Superfund/EPCRA Hotline at (800) 424-9346.
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4.3 REGULATORY STATUS
(TSDF) and thereby having to apply for a TSDF permit. The provisions of 40 CFR 262.34(f)
allow SQGs to store waste on-site for 270 days without having to apply for TSDF status
provided the waste must be transported over 200 miles. LQGs have only a 90-day window to
ship wastes off-site without needing a RCRA TSDF permit. Keep in mind that most provisions
of 40 CFR Parts 264 and 265 (for hazardous waste treatment, storage and disposal facilities) do
not apply to generators who send their wastes off-site within the 90- or 180-day window,
whichever is applicable.
Hazardous waste generators that do not meet the conditions for CESQGs must (among
other requirements such as record keeping and reporting):
• Obtain a generator identification number.
• Store and ship hazardous waste in suitable containers or tanks (for storage only).
• Manifest the waste properly.
• Maintain copies of the manifest, a shipment log covering all hazardous waste shipments,
and test records.
• Comply with applicable land disposal restriction requirements.
• Report releases or threats of releases of hazardous waste.
Treatment. Storage, or Disposal Facility Status
As mentioned above, Subtitle C of RCRA (40 CFR Parts 264 and 265) outlines
regulation and permit requirements for facilities that treat, store, or dispose of hazardous wastes.
Any generator (except some CESQGs [see 40 CFR Part 261.5(g)]), no matter what monthly
waste output, who treats, stores, or disposes of waste on site is classified as a treatment, storage,
or disposal facility (TSDF). Every TSDF must comply with 40 CFR Part 264-267 and Part 270,
including requirements to apply for a permit and meet certain stringent technical and financial
responsibility requirements. Generators who discharge hazardous waste into a POTW or from a
point source regulated by an NPDES permit are not required to comply with TSDF regulations,
nor are generators who store waste for short periods (see Generator Status, above).
4.3.5 Comprehensive Environmental Response, Compensation and Liability Act
The Comprehensive Environmental Response, Compensation and Liability Act (also
known as CERCLA, or more commonly as Superfund) was enacted in 1980. CERCLA is the
Act that created the Superfund hazardous substance cleanup program and set up a variety of
mechanisms to address risks to public health, welfare, and the environment caused by hazardous
substance releases.
CERCLA ROs
Substances deemed hazardous under CERCLA are listed in 40 CFR Section 302.4.
Under CERCLA, EPA has assigned a reportable quantity (RQ) to most hazardous substances;
regulatory RQs are either 1,10,100,1,000, or 5,000 pounds (except for radionuclides). If EPA
has not assigned a regulatory RQ to a hazardous substance, its RQ is one pound (Section 102).
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Any person in charge of a facility (or a vessel) must immediately (within a 24-hour period) notify
the National Response Center as soon as a person has knowledge of a release of an amount of a
hazardous substance that is equal to or greater than its RQ.4 There are some exceptions to this
requirement, including exceptions for certain continuous releases and for federally permitted
releases. Table 4.35 lists RQs of substances under CERCLA that may apply to chemicals used hi
the MHC process.
Table 4.35 CERCLA Reportable Quantities That May Apply to Chemicals in MHC
Technologies
Chemical
1,3-Benezenediol
Ammonia
Ammonia Chloride
Copper (I) Chloride
Copper Sulfate
Dimethyformamide
Ethyl Glycol
Formaldehyde
Formic Acid
Hydrochloric Acid
CERCLA RQ
0&s)
5,000
100
5,000
10
10
100
5,000
100
5,000
5,000
Chemical
Isophorone
Methanol
Phosphoric Acid
Potassium Cyanide
Potassium Hydroxide
Silver
Sodium Cyanide
Sodium Hydroxide
Sulfuric Acid
CERCLA RQ
(Ibs)
5,000
5,000
5,000
10
1,000
1,000
10
1,000
1,000
Abbreviations and definitions:
CERCLA - Comprehensive Environmental Response, Compensation and Liability Act
CERCLA RQ - CERCLA reportable quantity.
CERCLA Liability
CERCLA further makes a broad class of parties liable for the costs of removal or
remediation of the release or threatened release of any hazardous substance at a facility. Section
107 specifies the parties liable for response costs, including the following: 1) current owners and
operators of the facility; 2) owners and operators of facility at the time hazardous substances
were disposed; 3) persons who arranged for disposal or treatment, or for transportation for
disposal or treatment, of such substances; and 4) persons who accepted such substances for
transportation for disposal or treatment. These parties are liable for: 1) all costs of removal or
remedial action incurred by the federal government, a state, or an Indian tribe not inconsistent
with the National Contingency Plan (NCP); 2) any other necessary costs of response incurred by
any person consistent with the NCP; 3) damages for injury to natural resources; and 4) costs of
health assessments.
4 The national toll-free number for the National Response Center is (800) 424-8802; in Washington, DC., call
(202)426-2675.
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4.3.6 Superfund Amendments and Reauthorization Act and
Emergency Planning and Community Right-To-Know Act
CERCLA was amended in 1986 by the Superfund Amendments and Reauthorization Act
(SARA). Title III of SARA is also known as the Emergency Planning and Community Right-
To-Know Act (EPCRA). Certain sections of SARA and EPCRA may be applicable to MHC
chemicals and PWB manufacturers. Table 4.36 lists applicable provisions as related to specific
chemicals.
Table 4.36 SARA and EPCRA Regulations That May Apply to Chemicals in MHC
Technologies
Chemical
2-Ethoxyethanol
Ammonia
Copper (I) Chloride
Copper Sulfate
Dimethylformamide
Ethylene Glycol
EDTA
Fluoroboric Acid
(as fluoride)
Formaldehyde
Formic Acid
SARA
110
/
S
/
S
/
EPCRA
302a
^
/
EPCRA
313
/
S
S
S
S
S
S
s
s
Chemical
Hydrochloric Acid
Hydrogen Peroxide
Isopropyl Alcohol
Methanol
Phosphoric Acid
Potassium Cyanide
Silver
Sodium Cyanide
Stannous Chloride (as tin)
Sulfuric Acid
SARA
no
s
s
s
EPCRA
302a
/
/
/
/
S
EPCRA
313
/
/
/
S
/
/
S
S
SARA - Superfund Amendments and Reauthorization Act
SARA 110 - Superfund Site Priority Contaminant
EPCRA - Emergency Planning & Community Right-To-Know Act
EPCRA 302a - Extremely Hazardous Substances
EPCRA 313 - Toxic Chemical Release Inventory
SARA Priority Contaminants
SARA Section 110 addresses Superfund site priority contaminants. This list contains the
275 highest ranking substances of the approximately 700 prioritized substances. These chemical
substances, found at Superfund sites, are prioritized based on their frequency of occurrence,
toxicity rating, and potential human exposure. Once a substance has been listed, the Agency for
Toxic Substances and Disease Registry (ATSDR) is mandated to develop a toxicological profile
that contains general health/hazard assessments with effect levels, potential exposures, uses,
regulatory actions, and further research needs.
EPCRA Extremely Hazardous Substances
Section 302(a) of EPCRA regulates extremely hazardous substances and is intended to
facilitate emergency planning for response to sudden toxic chemical releases. These chemicals,
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4.3 REGULATORY STATUS
if present in quantities greater than their threshold planning quantities, must be reported to the
State Emergency Response Commission and Local Emergency Planning Committee and
addressed in community emergency response plans. These same substances are also subject to
regulation under EPCRA Section 304, which requires accidental releases hi excess of reportable
quantities to be reported to the same state and local authorities.
EPCRA Toxic Release Inventory
Under EPCRA Section 313, a facility in SIC Codes 20-39 that has ten or more full-time
employees and that manufactures, processes, or otherwise uses more than 10,000 or 25,000
pounds per year of any toxic chemical listed in 40 CFR Section 372.65 must file a toxic chemical
release inventory (TRI) reporting form (EPA Form R) covering releases of these toxic chemicals
(including those releases specifically allowed by EPA or state permits) with the EPA and a state
agency where the facility is located. Beginning with the 1991 reporting year, such facilities must
also report pollution prevention and recycling data for TRI chemicals pursuant to Section 6607 of
the Pollution Prevention Act, 42 USC 13106. The threshold for reporting releases is 10,000 or
25^000 pounds, depending on how the chemical is used (40 CFR Section 372.25). Form R is
filed annually, covers all toxic releases for the calendar year, and must be filed on or before the
first of July of the following year.
4.3.7 Toxic Substances Control Act
The Toxic Substances Control Act (TSCA)(40 CFR Part 700-799), originally passed in
1976 and subsequently amended, applies to the manufacturers, importers, processors,
distributors, users, and disposers of chemical substances or mixtures. Table 4.37 lists TSCA
regulations that may be pertinent to the MHC process.
Table 4.37 TSCA Regulations That May Apply to Chemicals in MHC Technologies
Chemical
Benzotriazole
Diethylene Glycol Methyl Ether
Dimethylformamide
Formaldehyde
Isophorone
Isopropyl Alcohol
TSCA
8d
HSDR
/
/
/
/
TSCA
5*
MTL
S
S
TSCA
Sa
PAIR
/
/
/
/
Chemical
Palladium Chloride
Silver
Sodium Cyanide
Triethanolamine
Vanillin
TSCA;
8d
HSDR
TSCA
8a
MTL
/
S
S
TSCA
Sa
PAIR
/
/
/
Abbreviations and definitions:
TSCA - Toxic Substances Control Act
TSCA 8d HSDR - Health & Safety Data Reporting Rules
TSCA MTL - Master Testing List
TSCA 8a PAIR - Preliminary Assessment Information Rule
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Testing Requirements
Section 4 authorizes EPA to require the testing of any chemical substance or mixture on
finding that such testing is necessary due to insufficient data from which the chemical's effects
can be predicted and that the chemical either may present an unreasonable risk of injury to health
or the environment or the chemical is produced in substantial quantities or may result in
substantial human exposure.
The TSCA Master Testing List (MTL) is a list compiled by EPA's Existing Chemicals
Program to set the Agency's testing agenda under TSCA Section 4. The major purposes are to:
1) identify chemical testing needs; 2) focus limited EPA resources on those chemicals with the
highest priority testing needs; 3) identify and publicize EPA's testing priorities for existing
chemicals; 4) obtain broad public comments on EPA's testing program and priorities; and 5)
encourage initiatives by Industry to help EPA meet those priority needs. Since 1990, EPA has:
1) added 222 specific chemicals and nine categories to the MTL; 2) deleted 45 chemicals from
the MTL; 3) proposed testing for 113 chemicals via proposed rulemaking under TSCA Section 4;
4) required testing for six chemicals and one category via final TSCA Section 4 test rules,
negotiated consent orders, or voluntary testing agreements; and 5) made risk assessment or
management decisions on 41 chemicals based on TSCA Section 4 test results received. The
MTL now contains over 320 specific chemicals and nine categories.
Existing Chemical Requirements
Section 6 authorizes EPA, to the extent necessary to protect adequately against
unreasonable risk using the least burdensome requirements, to prohibit the manufacture,
processing, or distribution in commerce of a chemical substance; to limit the amounts,
concentrations, or uses of it; to require labeling or record keeping concerning it; or to prohibit or
otherwise regulate any manner or method of disposal, on finding there is a reasonable basis to
conclude that the chemical presents or will present an unreasonable risk of injury to human
health or the environment.
Preliminary Assessment Information Rules
Section 8(a) of TSCA, the Preliminary Assessment Information Rules (PAIR), establishes
procedures for chemical manufacturers and processors to report production, use, and exposure-
related information on listed chemical substances. Any person (except a "small business") who
imports, manufactures, or processes chemicals identified by EPA by rule must report information
on production volume, environmental releases, and/or chemical releases. Small businesses are
required to report such Information in some circumstances.
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4.3.8 Occupational Safety and Health Act
OSHA Hazard Communication Standard
The Occupational Safety and Health Act (OSHA) governs the exposure of workers to
chemicals in the workplace. Any facility that is required by OSHA's Hazard Communication
Standard (29 CFR Section 1910.1200) to have Material Safety Data Sheets (MSDSs) for certain
hazardous chemicals, and that has such chemicals above certain minimum threshold levels, must
provide copies of the MSDSs for these substances or a list of the substances to the State
Emergency Response Commission (SERC), the Local Emergency Planning Commission
(LEPC), and the local fire department. MSDSs must also be made available to workers. In
addition, facilities must annually submit to the SERC, the LEPC, and the fire department a Tier I
report indicating the aggregate amount of chemicals (above threshold quantities) at their
facilities, classified by hazard category. If any agency that receives a Tier I report requests a Tier
II report requiring additional information, facilities must submit this second report to the agency
within 30 days of receiving a request for such a report. Tier II reports include an inventory of all
chemicals at the facility. Most of the chemicals used in the MHC technologies industry are
subject to these MSDS and Tier reporting requirements (40 CFR Part 370).
4.3.9 Summary of Regulations by MHC Technology
Tables 4.38 through 4.45 provide a summary of regulations that may apply to chemicals
in each of the MHC technology categories. Chemicals listed in bold in the tables are used in all
of the technology product lines evaluated. For example, formaldehyde is used in all of the
electroless copper lines evaluated in this study, but dimethylformamide is only used in one
product line. PWB manufacturers should check with their chemical supplier or review their
MSDSs to determine which chemicals are present in the products they use.
Chemicals and wastes from the MHC alternatives appear to be subject to fewer overall
federal environmental regulations than electroless copper. This suggests that implementing an
alternative could potentially improve competitiveness by reducing compliance costs.
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4-75
DRAFT
-------
4.3 REGULATORY STATUS
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DRAFT
4-76
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4.3 REGULATORY STATUS
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DRAFT
4-78
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4.3 REGULATORY STATUS
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DRAFT
4-79
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43 REGULATORY STATUS
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DRAFT
4-80
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4.3 REGULATORY STATUS
Table 4.44 Summary of Regulations That May Apply to Chemicals in the Organic-Palladium Technology
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4-81
DRAFT
-------
43 REGULATORY STATUS
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" Chemicals in bold were in all tin-pall
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DRAFT
4-82
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4.4 INTERNATIONAL INFORMATION
4.4 INTERNATIONAL INFORMATION
Several alternatives to the electroless copper process are being adopted more quickly
abroad than in the U.S. This section discusses the world market for PWBs and the international
use of MHC alternatives. It also discusses factors driving the international use of MHC
alternatives, including economic, environmental and regulatory considerations.
4.4.1 World Market for PWBs
The total world market for PWBs is approximately $21 billion (EPA, 1995c). The U.S.
and Japan are the leading suppliers of PWBs but Hong Kong, Singapore, Taiwan, and Korea are
increasing their market share. In 1994 the U.S. provided 26 percent of the PWBs in the world
market, Japan 28 percent, and Europe 18 percent (EPA, 1995c). IPC estimates that domestic
PWB imports are approximately $500 to $600 million annually (EPA, 1995c). Taiwan
comprises approximately 30 to 35 percent of the import market with Japan, Hong Kong, Korea,
and Thailand comprising 10 percent each. Domestic PWB exports were approximately $100
million in 1993, which represents two to three percent of total domestic production (EPA,
1995c).
4.4.2 International Use of MHC Alternatives
The alternatives to the traditional electroless copper MHC process are in use in many
countries abroad, including England, Italy, France, Spain, Germany, Switzerland, Sweden, Japan,
China, Hong Kong, Singapore, Taiwan, and Canada. In addition, most of the suppliers of these
alternatives have manufacturing facilities located in the countries to which they sell. One
company provides its palladium alternative to Japan, France, Sweden, the UK, Canada, and
Germany (Harnden, 1996). Another company, which provides a palladium alternative to
electroless copper, provides both processes to England, Italy, France, Spain, Germany,
Switzerland, China, Hong Kong, Singapore, and Taiwan. Presently, that company's electroless
copper process is used more frequently than the palladium alternative (Nargi-Toth, 1996).
However, restrictions on EDTA in Germany are making the use of the palladium alternative
almost equal to the use of the traditional electroless copper process. Similarly, in Taiwan and
China the use of the palladium process is increasing relative to the electroless copper process due
to the high cost of water (Nargi-Toth, 1996). Internationally, one company reports its conductive
polymer and organic-palladium processes make up approximately five percent of the world
market (Boyle, 1996).
Another company provides its graphite alternative in Germany, England, France, Japan,
Taiwan, and Hong Kong, and is opening manufacturing facilities in both China and Malaysia
within a few months (Carano, 1996). The company's graphite process is reportedly used more
frequently in Europe than is its electroless copper process. However, in Asia, the electroless
copper process is used more frequently (Carano, 1996).
Several suppliers have indicated that the use of their particular MHC alternative to
electroless copper is increasing throughout the international arena. Some suppliers have
DRAFT
4-83
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4.4 INTERNATIONAL INFORMATION
indicated that the international usage of the electroless copper process is also on the rise but that
the MHC alternatives are increasing in usage more rapidly than traditional electroless copper
processes (Carano, 1996). A pollution prevention and control survey performed under the DfE
PWB Project confirmed that the electroless copper is the predominate method employed in the
U.S. The survey was conducted of 400 PWB manufacturers in the U.S.; 40 responses were
received, representing approximately 17 percent of the total U.S. PWB production (EPA, 1995d).
Eighty-six percent of survey respondents use the electroless copper for most of their products, 14
percent use palladium alternatives, and 1 respondent uses a graphite system (EPA, 1995d). The
Pollution Prevention and Control Survey is discussed further in Chapter 1 of the CTSA.
Reasons for Use of Particular Alternatives Internationally
For the most part, the alternatives to the electroless copper process appear to be employed
due to reasons other than environmental pressures. According to international manufacturers
who participated hi the Performance Demonstration Project, the most common reason for use of
an alternative is economics. According to suppliers, some of the alternatives are in fact less
costly than the traditional electroless copper process (see Section 4.2 for an analysis of the
comparative costs of alternatives developed for the CTSA). An example of this is one
company's graphite process, which reportedly costs less than the company's comparable
electroless copper process (Carano, 1996). Furthermore, several of the performance
demonstration participants in Europe indicated that their use of an alternative MHC process has
resulted in increased throughput and decreased manpower requirements.
Some of the economic drivers for adopting alternatives to the electroless copper process
internationally also relate to environmental issues. Several of the countries adopting the MHC
alternatives have high population densities as compared to the U.S., making water a scarcer
resource. As a result, these companies face high costs to buy and treat their wastewater. In
Germany, for example, companies pay one cent per gallon to have water enter the plant and then
must pay 1.2 cents per gallon to dispose of wastewater (Obermann, 1996). As a result, any
alternative that offers a reduction in the use of wastewater is potentially more attractive from a
cost-effectiveness standpoint. Several MHC alternatives allow wastewater to be reused a number
of times, something that is not available when using the electroless copper process due to the
high levels of chelators and copper that cannot be removed from the water except through
chemical treatment (Obermann, 1996). Therefore, the costs of buying the water and paying to
have it treated are reduced through the use of less water-intensive alternatives.
In some countries there are "pressures" rather than environmental regulations that have
led to the adoption of an alternative to the electroless copper MHC process. Some countries have
identified the use of EDTA and formaldehyde as areas of potential concern. For instance, in
Germany there are restrictions on the use of the chelator EDTA that are making the adoption of
non-EDTA using alternatives more attractive (Nargi-Toth, 1996). Some alternatives do not use
formaldehyde and as such are used with more frequency than the electroless copper process in
countries that are attempting to limit the use of formaldehyde (Harnden, 1996).
DRAFT
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4.4 INTERNATIONAL INFORMATION
Barriers to Trade and Supply Information
The alternatives to the electroless copper process do not suffer from any readily apparent
barriers to trade or tariff restrictions that would make their increased adoption more costly. The
alternatives discussed above are all made from readily available materials. Therefore, if the
demand for these alternatives should increase there should be no problem with meeting the
increased demand. Most of the suppliers of these alternatives have manufacturing facilities
located in the countries to which they sell and so they face no tariffs from importing these
chemicals. The companies that wish to use the particular alternative simply contact the
manufacturer in their country to purchase the alternatives. Therefore, there are no trade barriers
in the form of tariffs making one alternative more attractive to a potential purchaser (Carano,
1996; Nargi-Toth, 1996; Harnden, 1996). As was indicated above, most alternatives are
available in the same countries so they all appear to be on equal footing in terms of availability
and susceptibility to trade barriers.
4.4.3 Regulatory Framework
Most of the driving forces leading to the use of an alternative to electroless copper are
related to the cost-effectiveness of the alternative. However, there are several regulatory
mechanisms in place internationally that favor alternatives to traditional electroless copper
processes. These include wastewater effluent requirements and water consumption issues,
discussed below.
Wastewater Effluent Requirements
Suppliers and international performance demonstration participants report that
economics, not chemical bans or restrictions on specific chemicals, are the leading cause for the
adoption of an MHC alternative. However, wastewater effluent requirements for certain
chemicals found in electroless copper processes are also speeding the adoption of other MHC
processes. For example, in Germany the chemical EDTA is restricted so that it must be removed
from wastewater before the wastewater is discharged to an off-site wastewater treatment facility.
This restriction led one manufacturer to replace his electroless copper process with an organic-
palladium process (Schwansee, 1996). This restriction is a national one so that all companies
must adhere to it.
Also in Germany, the wastewater leaving a plant cannot contain copper in amounts in
excess of 0.5 mg/L or any ammonia (Obermann, 1996). The German regulation on copper
discharges is much more stringent than comparable regulations in the U.S., where facilities must
at least comply with federal effluent regulations and are sometimes subjected to more stringent
regulations from the states (EPA, 1995d). The federal effluent guidelines for copper discharges
are 3.38 mg/1 maximum and 2.07 mg/1 average monthly concentration (EPA, 1995d).
According to the Pollution Prevention and Control Survey discussed previously, 63 percent of
the respondents must meet discharge limitations that are more stringent than the federal effluent
limitations (EPA, 1995d). However, only 15 percent of the respondents had to meet effluent
DRAFT
4-85
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4.4 INTERNATIONAL INFORMATION
limitations that were as stringent as, or more stringent than, the German regulation (EPA
1995d).
Water Consumption
As indicated above, water usage is a main concern in many of the international arenas
that use these alternatives. While there are few direct regulations on the amount of water that can
be used in a MHC process, the cost of buying and treating the water make a more water-intensive
process less economical. In Germany, the high cost of purchasing water and discharging
wastewater greatly influences the decision of whether or not to use to use an alternative. The
less water a process uses, the more likely it is that process will be used. In addition, in certain
parts of Germany, local authorities examine plans for the MHC process and issue permits to
allow use of the line. If the process that is proposed for use is too water-intensive, a permit will
not be issued by the local authorities (Carano, 1996). In addition, local authorities sometimes
give specific time limits in which an older more water-intensive process must be phased out
(Carano, 1996). For example, one international participant in the Performance Demonstration
Project uses an older electroless copper process for some of its products. The local authorities
have given the company four years to cease operation of the line because it uses too much water
(Obermann, 1996).
4.4.4 Conclusions
The information set forth above indicates that the cost-effectiveness of an alterative has
been the main driver causing PWB manufacturers abroad to switch from an electroless copper
process to one of the newer alternatives. In addition to the increased capacity and decreased
labor requirements of some of the MHC alternatives over the non-conveyorized electroless
copper process, environmental concerns also affected the process choice. For instance, the rate at
which an alternative consumes water and the presence or absence of strictly regulated chemicals
are two factors which have a substantial affect on the cost-effectiveness of MHC alternatives
abroad. Finally, in some parts of Germany, local authorities can deny a permit for a new MHC
process line if it is deemed too water-intensive, or require an existing MHC process to be
replaced. While environmental regulations do not seem to be the primary forces leading toward
the adoption of the newer alternatives, it appears that the companies that supply these alternatives
are taking environmental regulations and concerns into consideration when designing alternatives
to the electroless copper process.
DRAFT
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REFERENCES
REFERENCES
Badgett, Lona, Beth Hawke and Karen Humphrey. 1995. Analysis of Pollution Prevention and
Waste Minimization Opportunities Using Total Cost Assessment: A Study in the
Electronics Industry. Seattle, Washington. Pacific Northwest Pollution Prevention
Research Center Publication.
Boyle, Mike. 1996. Atotech, USA. 1996, Telephone discussion with Christine Dummer,
UT Center for Clean Products and Clean Technologies. July 19.
Carano, Mike. 1996. Electrochemicals. Telephone discussion with Christine Dummer,
UT Center for Clean Products and Clean Technologies. July 8.
Circuit Chemistry. 1996. Personal Communication with sales representative of Circuit
Chemistry, Golden Valley, MN (612-591-0297). June.
Coates AST. 1996. Personal communication with sales representative of Coates ASI,
Hutchinson, MN (320-587-7555) and Phoenix, AZ (602-276-7361). June.
DeGarmo, E. Paul, William G. Sullivan and James A. Bontadelli. 1996. Engineering
Economy, lOthed. New York, New York: Macmillan Publishing Co.
Ferguson, John H. 1996. Means Square Foot Costs: Means-Southern Construction Information
Network. Kingston, MA: R.S. Means Co., Inc. Construction. Publishers and
Consultants.
Fisher, Helen S. 1995. American Salaries and Wages Survey, 3rd ed. Detroit, MI: Gale
Research Inc. (An International Thompson Publishing Co.)
Harnden, Eric. 1996. Solution Technological Systems. Telephone discussion with Christine
Dummer, UT Center for Clean Products and Clean Technologies. June 28.
KUB. 1996a. Knoxville Utilities Board, Personal communication with Jim Carmen's (Senior
VP of Gas Division) office, Knoxville, TN (423-524-2911).
KUB. 1996b. Knoxville Utilities Board. Personal communication with Bill Elmore's (VP)
office, Knoxville, TN (423-524-2911).
Microplate. 1996. Personal communication with sales representative of Microplate, Clearwater,
FL (813-577-7777). June.
Nargi-Toth, Kathy. 1996. Enthone-OMI. Telephone discussion with Christine Dummer,
UT Center for Clean Products and Clean Technologies. July 1.
DRAFT
4-87
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REFERENCES
Obermann, Alfons. 1996. Metalex GmbH. Telephone discussion with Christine Dummer,
UT Center for Clean Products and Clean Technologies. July 3.
PAL Inc. 1996. Personal communication with sales representative of PAL, Inc., Dallas, TX
(214-298-9898). June.
Schwansee, Gunther. 1996. Schoeller Elektronik GmbH. Telephone discussion with Christine
Dummer, UT Center for Clean Products and Clean Technologies. July 3.
U.S. Environmental Protection Agency (EPA). 1995a. Pollution Prevention and Control
Survey. EPA's Office of Prevention, Pesticides, and Toxic Substances, Washington, DC.
EPA 744-R-95-006.
U. S. Environmental Protection Agency (EPA). 1995b. Federal Environmental Regulations
Affecting the Electronics Industry. EPA's Office of Prevention, Pesticides, and Toxic
Substances. EPA744-B-95-001. September.
U.S. Environmental Protection Agency (EPA). 1995c. Printed Wiring Board Industry and Use
Cluster Profile. Design for the environment Printed Wiring Board Project. September.
U.S. Environmental Protection Agency (EPA). 1995d. Printed Wiring Board Pollution
Prevention and Control: Analysis of Survey Results, Design for the Environment Printed
Wiring Board Project. September.
U.S. Environmental Protection Agency (EPA). 1996. Register of Lists. ECLIPS Software, 13th
update (Fall, 1995). Version: Government. Washington, DC.
Vishanoff, Richard. 1995. Mar shall Valuation Service: Marshall and Swift the Building Cost
People. Los Angeles, CA: Marshall and Swift Publications.
Western Technology Associates. 1996. Personal communication with sales representative of
Western Technology Associates, Anaheim, CA (714-632-8740).
White, Allan L., Monica Becker and James Goldstein. 1992. Total Cost Assessment:
Accelerating Industrial Pollution Prevention Through Innovative Project Financial
Analysis: With Application to Pulp and Paper Industry. EPA's Office of Pollution
Prevention and Toxics, Washington, DC.
DRAFT
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Chapter 5
Conservation
Businesses are finding that by conserving natural resources and energy they can cut costs,
improve the environment, and improve their competitiveness. And due to the substantial amount
of rinse water consumed and wastewater generated by traditional electroless copper processes,
water conservation is an issue of particular concern to printed wiring board (PWB) manufacturers
and to the communities in which they are located. This chapter of the Cleaner Technologies
Substitutes Assessment (CTSA) evaluates the comparative resource consumption and energy use
of the making holes conductive (MHC) technologies. Section 5.1 presents a comparative
analysis of the resource consumption rates of MHC technologies, including the relative amounts
of rinse water consumed by the technologies and a discussion of factors affecting process and
wastewater treatment chemicals consumption. Section 5.2 presents a comparative analysis of the
energy impacts of MHC technologies, including the relative amount of energy consumed by each
MHC process, the environmental impacts of this energy consumption, and factors affecting
energy consumption during other life-cycle stages, such as chemical manufacturing or MHC
waste disposal.
5.1 RESOURCE CONSERVATION
Resource conservation is an increasingly important goal for all industry sectors,
particularly as global industrialization increases demand for limited resources. A PWB
manufacturer can conserve resources through his or her selection of an MHC process and the
manner in which it is operated. By reducing the consumption of resources, a manufacturer will
not only minimize process costs and increase process efficiency, but will also conserve resources
throughout the entire life-cycle chain. Resources typically consumed by the operation of the
MHC process include water used for rinsing panels, process chemicals used on the process line,
energy used to heat process baths and power equipment, and wastewater treatment chemicals.
The focus of this section is to perform a comparative analysis of the resource consumption rates
of the baseline and alternative MHC technologies. Section 5.1.1 discusses the types and
quantities of natural resources (other than energy) consumed during MHC operation. Section
5.1.2 presents conclusions of this analysis.
5.1.1 Natural Resource Consumption
To determine the effects that alternatives have on the rate of natural resource
consumption during the operation of the MHC process, specific data were gathered through the
Performance Demonstration Project, a survey of chemical suppliers, and dissemination of the
Workplace Practices Survey to industry. Natural resource data gathered through these means
include the following:
• Process specifications (i.e., type of process, facility size, process throughput, etc.).
DRAFT
5-1
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5.1 RESOURCE CONSERVATION
• Physical process parameters and equipment description (i.e., automation level, bath size,
rinse water system configuration, pollution prevention equipment, etc.).
• Operating procedures and employee practices (i.e., process cycle-time, individual bath
dwell times, bath maintenance practices, chemical disposal procedures, etc.).
• Resource consumption data (i.e., rinse water flow rates, frequency of bath replacement,
criteria for replacement, bath formulations, frequency of chemical addition, etc.).
Using the collected data, a comparative analysis of the water consumption rates for each
of the MHC alternatives was developed. For both process chemical and treatment chemical
consumption, however, statistically meaningful conclusions could not be drawn from the
compiled data. Differences in process chemicals and chemical product lines, bath maintenance
practices, and process operating procedures, just to name a few possibilities, introduced enough
uncertainly and variability to prevent the formulation of quantifiable conclusions. A qualitative
analysis of these data is therefore presented and factors affecting the chemical consumption rates
are identified. Table 5.1 summarizes the types of resources consumed during the MHC operation
and the effects of the MHC alternatives on resource conservation. Water, process chemicals, and
treatment chemicals consumption are discussed below.
Table 5.1 Effects of MHC Alternatives on Resource Consumption
Resource
Water
Process Chemicals
Energy
Treatment Chemicals
Effects of MHC Alternative on Resource Consumption
Water consumption can vary significantly according to MHC alternative and
level of automation. Other factors such as water and sewage costs and operating
practices also affect water consumption rates.
Reduction in the number of chemical baths comprising MHC substitutes
typically leads to reduced chemical consumption. The quantity of process
chemicals consumed is also dependent on other factors such as expected bath
lives (e.g., the number of surface square feet (ssf) processed before a bath must
be replaced or chemicals added), process throughput, and individual facility
operating practices.
Energy consumption rates can differ substantially among the baseline and
alternatives. Energy consumption is discussed in Section 5.2.
Water consumption rates and the associated quantities of wastewater generated
as well as the elimination of chelators from the MHC process can result in
differences in the type and quantity of treatment chemicals consumed.
Water Consumption
The MHC process line consists of a series of chemical baths which are typically separated
by one, and sometimes several, water rinse steps. These water rinse steps account for virtually
all of the water consumed during the operation of the MHC process. The water baths dissolve or
displace residual chemicals from the panel surface, preventing contamination of subsequent
baths, while creating a clean panel surface for future chemical activity. The number of rinse
stages recommended by chemical suppliers for their MHC processes range from two to seven,
but can actually be much higher depending on facility operating practices. The number of rinse
stages reported by respondents to the Workplace Practices Survey ranged from two to fifteen
separate water rinse stages.
DRAFT
5-2
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5.1 RESOURCE CONSERVATION
The flow rate required by each individual rinse tank to fulfill its role in the process is
dependent on several factors, including the time of panel submersion, the type and amount of
chemical residue to be removed, the type of agitation used in the rinse stage, and the purity of
rinse water. Because proper water rinsing is critical to the MHC process, manufacturers often
use more water than is required to ensure that panels are cleaned sufficiently. Other methods,
such as flow control valves and sensors, are available to ensure that sufficient water is available
to rinse PWB panels, while minimizing the amount of water consumed by the process.
PWB manufacturers often use multiple rinse water stages between chemical process steps
to facilitate better rinsing. The first rinse stage removes the majority of residual chemicals and
contaminants, while subsequent rinse stages remove any remaining chemicals. Counter-current
or cascade rinse systems minimize water use by feeding the water effluent from the cleanest rinse
tank, usually at the end of the cascade, into the next cleanest rinse stage, and so on, until the
effluent from the most contaminated, initial rinse stage is sent for treatment or recycle. Other
water reuse or recycle techniques include ion exchange, reverse osmosis, as well as reusing rinse
water in other plant processes. A detailed description of methods to reduce water consumption,
including methods to reuse or recycle contaminated rinse water, is presented in Chapter 6 of this
CTSA.
To assess the water consumption rates of the different process alternatives, data from
chemical suppliers and the Workplace Practices Survey were used and compared for consistency.
Estimated water consumption rates for each alternative were provided by chemical suppliers for
each MHC process. Consumption rates were reported for three categories of manufacturing
facilities based on board surface area processed in ssf per day: small (2,000 - 6,000), medium
(6,000 - 15,000), and large (15,000 +). Water consumption rates for each alternative were also
calculated using data collected from the Workplace Practices Survey. An average water flow
rate per rinse stage was calculated for both non-conveyorized (1,840 gal/day per rinse stage) and
conveyorized processes (1,185 gal/day per rinse stage) from the survey data collected. The
average flow rate was then multiplied by the number of rinse stages in the standard configuration
for each process (see Section 3.1, Source Release Assessment) to generate a water consumption
rate per day for each MHC alternative. The number of rinse stages in a standard configuration of
an alternative, the daily rinse water flow rate calculated from the Workplace Practices Survey,
and the daily water flow rate reported by chemical suppliers for each MHC alternative are
presented in Table 5.2.
To determine the overall amount of rinse water consumed by each alternative, the rinse
water flow rate from Table 5.2 was multiplied by the amount of time needed for each alternative
to manufacture 3 50,000 ssf of board (the average MHC throughput of respondents to the
Workplace Practices Survey). The operating time required to produce the panels was simulated
using a computer model developed for each MHC alternative. For the purposes of this
evaluation it was assumed that the water flow to the rinse stages was turned off during periods of
MHC process shutdown (e.g., bath replacements). The results of the simulation along with a
discussion of the data and parameters used to define each alternative are presented in Section 4.2,
Cost Analysis. The days of MHC operation required to manufacture 350,000 ssf from the
simulation, the total amount of rinse water consumed for each MHC alternative, and the water
DRAFT
5-3
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5.1 RESOURCE CONSERVATION
consumption per ssf of board produced are presented in Table 5.3. The amount of rinse water
consumed for each alternative is also displayed in Figure 5.1.
Table 5.2 Rinse Water Flow Rates for MHC Process Alternatives
MOHC Process Alternative ;
Electroless Copper, non-conveyorized (BASELINE)
Electroless Copper, conveyorized
Carbon, conveyorized
Conductive Polymer, conveyorized
Graphite, conveyorized
Non-Formaldehyde Electroless Copper, non-conveyorized
Organic-Palladium, non-conveyorized
Organic-Palladium, conveyorized
Tin-Palladium, non-conveyorized
Tin-Palladium, conveyorized
No. of
Rinse
Stages3
7
7
4
4
2
5
5
5
4
4
MHC Riase Water Flow Rate
(gal/day)
Workplace
Practices Survey*
12,880
8,300
4,740
4,740
2,370
9,200
9,200
5,930
7,360
4,740
Supplier Data
Sheet'
5,700 - 12,500
3,840
ND
ND
1,400 - 3,800
ND
ND
ND
4,300 - 9,400
2,900 - 7,200
* Data reflects the number of rinse stages required for the standard configuration of each MHC alternative as
reported in Section 3.1, Source Release Assessment. Multiple rinse tanks in succession were considered to be
cascaded and thus were counted as a single rinse stage with respect to water usage.
b Rinse water flow rate was calculated by averaging water flow data per stage from both survey and performance
demonstrations (non-conveyorized = 1,840 gals/day per rinse stage; conveyorized =1,185 gals/day per rinse stage)
and then multiplying by the number of rinse stages in each process.
c Data ranges reflect estimates provided by chemical suppliers for facilities with process throughputs ranging from
2,000 - 15,000 ssf per day.
ND - No Data.
An analysis of the data shows that the type of MHC process, as well as the level of
automation, have a profound effect on the amount of water that a facility will consume dining
normal operation of the MHC line. All of the MHC alternatives have been demonstrated to
consume less water during operation than the traditional non-conveyorized electroless copper
process. The reduction in water usage is primarily attributable to the decreased number of rinse
stages required by many of the alternative processes and the decreased operating time required to
process a set number of boards. The table also demonstrates that the conveyorized version of a
process typically consumes less water during operation than the non-conveyorized version of the
same process, a result attributed to the decreased number of rinse steps required and the greater
efficiency of conveyorized processes. Some companies have gone a step farther by developing
equipment systems that monitor water quality and usage in order to optimize water rinse
performance, a pollution prevention technique recommended to reduce water consumption and,
thus, wastewater generation. The actual water usage experienced by manufacturers employing
such a system may be less than that calculated hi Table 5.3.
DRAFT
5-4
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5.1 RESOURCE CONSERVATION
Table 5.3 Total Rinse Water Consumed by MHC Process Alternatives by Board
Production Rate
MHC Process Alternative
Electroless Copper, non-conveyorized (BASELINE)
Electroless Copper, conveyorized
Carbon, conveyorized
Conductive Polymer, conveyorized
Graphite, conveyorized
Non-Formaldehyde Electroless Copper, conveyorized
Organic-Palladium, non-conveyorized
Organic-Palladium, conveyorized
Tin-Palladium, non-conveyorized
Tin-Palladium, conveyorized
Process
Operating
Time"
(days)
317.5
48.4
95.6
53.9
66.1
142.8
51.5
67.0
85.5
41.8
Rinse Water
Consumed
(gal/350,000 ssf)
4.09 x 106
4.02 xlO5
4.53 x 105
2.55 x 105
1.57xl05
1.31 xlO6
4.74 x 105
3.97 x 10s
6.29 x 105
1.98 x 10s
Water
Consumption
Rate
(gaVssf)
11.7
1.15
1.29
0.73
0.45
3.74
1.35
1.13
1.80
0.57
Operating time is reported in the number of days required to produce 350,000 ssf of board with a day equal to 6.8
hours of process operating time. Rinse water was assumed to be turned off during periods of process shutdown,
thus the simulated operating time for each alternative was adjusted to exclude these periods of shutdown. For a
more detailed description of the simulation model see Section 4.2, Cost Analysis.
Figure 5.1 Water Consumption Rates of MHC Alternatives
Graphite [c]
Tin-Palladium [c]
Conductive Polymer [c]
Organic-Palladium [c]
Electroless Copper [c]
Carbon [c]
Organic-Palladium [nc]
Tin-Palladium [nc]
Non-Formaldehyde Electroless Copper [nc]
Electroless Copper [nc]
4 6 8 10 12
(gal/ssf)
c: conveyorized
nc: non-conveyorized
5-5
DRAFT
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5.1 RESOURCE CONSERVATION
A study of direct metallization processes conducted by the City of San Jose, California
also identified reduced rinse water consumption as one of the many advantages of MHC
alternatives (City of San Jose, 1996). The study, performed by the city's Environmental Services
Department, included a literature search of currently available MHC alternatives, a survey of
PWB manufacturing facilities in the area, and a comparative analysis of the advantages of MHC
alternatives to electroless copper. The study report also presents several case studies of
companies that have already implemented MHC alternatives. The study found that 14 out of 46
(30 percent) survey respondents cited reduced water usage as a prominent advantage of replacing
their electroless copper MHC process with an alternative. On a separate survey question another
five survey respondents indicated that high water use was a prominent disadvantage of operating
an electroless copper MHC process. Although a couple of the companies studied reported little
reduction in water usage, several other companies implementing MHC alternatives indicated
decreases in water consumption. The study concluded that the magnitude of the reduction in
water consumption is site-specific depending on the facility's former process set-up and
operating practices.
Process Chemicals Consumption
Some of the resources consumed through the operation of the MHC process are the
chemicals that comprise the various chemical baths or process steps. These chemicals are
consumed through the normal operation of the MHC process line by either deposition onto the
panels or degradation caused by chemical reaction. Process chemicals are also lost through
volatilization, bath depletion, or contamination as PWBs are cycled through the MHC process.
Process chemicals are incorporated onto the panels, lost through drag-out to the following
process stages, or become contaminated through the build-up of impurities requiring the
replacement of the chemical solution. Methods for limiting unnecessary chemical loss and thus
minimizing the amount of chemicals consumed are presented in Chapter 6 in this CTSA.
Performing a comparative analysis of the process chemical consumption rates is difficult
due to the variability and site-specific nature of many of the factors that contribute to process
chemical consumption. Factors affecting the rate at which process chemicals are consumed
through the operation of the MHC process include:
• Characteristics of the process chemicals (i.e., composition, concentration, volatility, etc.).
• Process operating parameters (i.e., number of chemical baths, process throughput,
automation, etc.).
• Bath maintenance procedures (i.e., frequency of bath replacement, replacement criteria,
frequency of chemical additions, etc.).
The chemical characteristics of the process chemicals do much to determine the rate at
which chemicals are consumed in the MHC process. A chemical bath containing a highly
volatile chemical or mixture of chemicals can experience significant chemical losses to the air.
A more concentrated process bath will lose a greater amount of process chemicals in the same
volume of drag-out than a less concentrated bath. These chemical characteristics not only vary
DRAFT
5-6
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5.1 RESOURCE CONSERVATION
among MHC alternatives, but can also vary considerably among MHC processes offered by
different chemical suppliers within the same MHC alternative category.
The physical operating parameters of the MHC process is a primary factor affecting the
consumption rate of process chemicals. One such parameter is the number of chemical baths that
comprise the MHC process. Many of the MHC alternatives have reduced the number of
chemical process baths, not counting rinse stages, through which a panel must be processed to
perform the MHC function. The number of chemical baths in an MHC technology category
range from eight for electroless copper to four in the graphite substitute. The process throughput,
or quantity of PWBs being passed through the MHC process, also affects chemical usage since
the higher the throughput, the more process chemicals are consumed. However, conveyorized
processes tend to consume less chemicals per ssf than non-conveyorized versions of the same
process due to the smaller bath sizes and higher efficiencies of the automated processes.
The greatest impact on process chemical consumption can result from the bath
maintenance procedures of the facility operating the process. The frequency with which baths
are replaced and the bath replacement criteria used are key chemical consumption factors.
Chemical suppliers typically recommend that chemical baths be replaced using established
testing criteria such as concentration thresholds of bath constituents (e.g., 2 g/L of copper
content). Other bath replacement criteria include ssf of PWB processed and elapsed time since
the last bath replacement. The practice of making regular adjustments to the bath chemistry
through additions of process chemicals consumes process chemicals, but extends the operating
life of the process baths. Despite the supplier recommendations, survey data showed a wide
range of bath replacement practices and criteria for manufacturing facilities operating the same,
as well as different, MHC technologies.
A quantitative analysis of the consumption of process chemicals could not be performed
due to the variability of factors that affect the consumption of this resource. Chemical bath
concentration and composition differs significantly among MHC alternatives, but can also differ
considerably among chemical product lines within an MHC alternative category. Facilities
operating the same MHC alternative may have vast differences in both their MHC operating
parameters and bath maintenance procedures which can vary significantly from shop-to-shop and
from process-to-process. Because chemical consumption can be significantly affected by so
many factors not directly attributable to the type of MHC alternative (i.e., process differences
within an alternative, facility operating practices, bath maintenance procedures, etc.) it is difficult
to perform any quantitative analysis of chemical consumption among alternatives. Further
analysis of these issues is beyond the scope of this project and is left to future research efforts.
Wastewater Treatment Chemicals Consumption
The desire to eliminate chelating agents from the MHC process has been a factor in the
movement away from electroless copper processes and toward the development of substitute
MHC processes. Chelators are chemical compounds that inhibit precipitation by forming
chemical complexes with metals, allowing the metals to remain soluble in solution well past their
normal solubility limits. The elimination of chelating compounds from MHC wastewater greatly
DRAFT
5-7
-------
5.1 RESOURCE CONSERVATION
simplifies the chemical precipitation process required to effectively treat the streams. A detailed
description of the treatment process for both chelated and non-chelated wastes, as well as a
discussion of the effect of MHC alternatives on wastewater treatment, is presented in Section 6.2,
Recycle, Recovery and Control Technologies Assessment.
The extent to which the consumption of treatment chemicals will be reduced, if any, is
dependant on several factors, some of which include the rate at which wastewater is generated
(e.g., the amount of rinse water consumed), the type of treatment chemicals used, composition of
waste streams from other plant processes, percentage of treatment plant throughput attributable
to the MHC process, the resulting reduction in MHC waste volume realized, and the extent to
which the former MHC process was optimized for waste reduction. Because many of the above
factors are site-specific and not dependent on the type of MHC process a quantitative evaluation
would not be meaningful. However, the San Jose study mentioned previously addressed this
issue qualitatively.
The San Jose study found that 21 out of 46 (46 percent) survey respondents cited ease of
waste treatment as a prominent advantage of MHC alternatives. In response to a separate
question, 8 out of 46 (17 percent) respondents cited copper-contaminated wastewater as a
prominent disadvantage of electroless copper. Most of the facilities profiled in the study
reported mixed results with regard to the effects of MHC alternatives on wastewater treatment
chemical usage. Although several companies reported a decrease in the amount of treatment
chemicals consumed, others reported no effect or a slight increase in consumption. It was
concluded that the benefits of the reduction or elimination of chelators and their impact on the
consumption of treatment chemicals is site-specific (City of San Jose, 1996).
5.1.2 Conclusions
A comparative analysis of the water consumption rates was performed for the MHC
process alternatives. The daily water flow rate was developed for the baseline and each
alternative using survey data provided by industry. A computer simulation was used to
determine the operating time required to produce 350,000 ssf of PWB for each technology and a
water consumption rate was determined. Calculated water consumption rates ranged from a low
of 0.45 gal/ssf for the graphite process to a high of 11.7 gal/ssf for the non-conveyorized
electroless copper process. The results indicate all of the alternatives consume significantly less
water than the traditional non-conveyorized electroless copper process. Conveyorized processes
were found to consume less water than non-conveyorized versions of the same process.
A quantitative analysis of both process chemicals and treatment chemicals consumption
could not be performed due to the variability of factors that affect the consumption of these
resources. The role the MHC process has in the consumption of these resources was presented
and the factors affecting the consumption rates were identified.
DRAFT
5-8
-------
5.2 ENERGY IMPACTS
5.2 ENERGY IMPACTS
Energy conservation is an important goal for PWB manufacturers, as companies strive to
cut costs and seek to improve environmental performance and global competitiveness. Energy
use has become an important consideration in the manufacture of PWBs as much of the
manufacturing process requires potentially energy-intensive operations, such as the addition of
heat to process baths. This is especially true in the operation of the MHC process, where energy
is consumed by immersion heaters, fluid pumps, air blowers, agitation devices such as vibrating
motors, and by conveyorized transport systems. The focus of this section is to perform a
comparative analysis of the relative energy consumption rates of the baseline MHC process and
process alternatives and to qualitatively assess their relative energy impacts throughout the
product life cycle.
Data collected for this analysis focus on the use of MHC chemical products in PWB
manufacturing. Although a quantitative life-cycle analysis is beyond the scope and resources of
this project, a qualitative discussion of other life-cycle stages is presented, including a discussion
of the energy impacts of manufacturing or synthesizing the chemical ingredients of MHC
products, as well as a discussion of the relative life-cycle environmental impacts resulting from
energy consumption during the use of MHC chemicals. Section 5.2.1 discusses energy
consumption during MHC process operation. Section 5.2.2 discusses the environmental impacts
of this energy consumption, while Section 5.2.3 discusses energy consumption of other life-cycle
stages. Section 5.2.4 presents conclusions of the comparative energy analysis.
5.2.1 Energy Consumption During MHC Process Operation
To determine the relative rates of energy consumption during the operation of the MHC
technologies, specific data were collected regarding energy consumption through the
Performance Demonstration project and through dissemination of the Workplace Practices
Survey to industry members. Energy data collected include the following:
• Process specifications (i.e., type of process, facility size, etc.).
• Physical process parameters (i.e., number of process baths, bath size, bath conditions
such as temperature and mixing, etc.).
• Process automation (i.e., conveyorized, computer-controlled hoist, manual, etc.).
• Equipment description (i.e., heater, pump, motor, etc.).
• Equipment energy specifications (i.e., electric load, duty, nominal power rating,
horsepower, etc.).
Each of the MHC process alternatives consist of a series of chemical baths which are
typically separated by one or more water rinse steps. In order for the process to perform
properly, each chemical bath should be operated within specific supplier recommended
parameters, such as parameters for bath temperature and mixing. Maintaining these chemical
baths within the desired parameters often requires energy-consuming equipment such as
immersion heaters, fluid circulation pumps, and air blowers. In addition, the degree of process
automation affects the relative rate of energy consumption. Clearly, conveyorized equipment
DRAFT
5-9
-------
5.2 ENERGY IMPACTS
requires energy to operate the system, but also non-conveyorized systems require additional
equipment not found in conveyorized systems, such as panel agitation equipment.
Table 5.4 lists the types of energy-consuming equipment used in MHC process lines and
the function of the equipment. In some cases, one piece of equipment may be used to perform a
function for the entire process line. For example, panel vibration is typically performed by a
single motor used to rock an apparatus that extends over all of the process tanks. The apparatus
provides agitation to each individual panel rack that is connected to it, thus requiring only a
single motor to provide agitation to every bath on the process line that may require it. In other
cases, each process bath or stage may require a separate piece of energy-consuming equipment.
Table 5.4 Energy-Consuming Equipment Used in MHC Process Lines
Type of Equipment
Conveyor Drive Motor
Immersion Heater
Fluid Pump
Air Pump
Panel Agitation Motor
Gas Heater
Ventilation Equipment
Function
Powers the conveyor system required to transport PWB panels through the
MHC process.
Raise and maintain temperature of a process bath to the optimal operating
temperature.
Circulate bath fluid to promote flow of bath chemicals through drilled
through-holes and to assist filtering of impurities from bath chemistries.
Compress and blow air into process baths to promote agitation of bath to
ensure chemical penetration into drilled through-holes. Also provides
compressed air to processes using air knife to remove residual chemicals
from PWB panels.
Agitate apparatus used to gently rock panel racks back and forth in process
baths. Not required for conveyorized processes.
Heat PWB panels to promote drying of residual moisture remaining on the
panel surface.
Provides ventilation required for MHC bath chemistries and to exhaust
chemical fumes.
To assess the energy consumption rate of each of the MHC alternatives, an energy use
profile was developed for each MHC technology that identified typical sources of energy
consumption during the operation of the MHC process. The number of MHC process stages that
result in the consumption of energy during then- operation was determined from Performance
Demonstration and Workplace Practices Survey data. This information is listed in Table 5.5
according to the function of the energy-consuming equipment. For example, a typical non-
conveyorized electroless copper process consists of four heated process baths, two baths
requiring fluid circulation, and a single process bath that is air sparged. The panel vibration is
typically performed by a single motor used to rock an apparatus that extends over all of the
process tanks. Ventilation equipment is not presented in Table 5.5 because the necessary data
were not collected during the Performance Demonstration or in the Workplace Practices Survey.
However, the amount of ventilation required varies according to the type of chemicals, bath
operating conditions, and the configuration of the process line. Because they are enclosed, the
ventilation equipment for conveyorized processes are typically more energy efficient than non-
conveyorized processes.
DRAFT
5-10
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5.2 ENERGY IMPACTS
Table 5.5 Number of MHC Process Stages that Consume Energy by Function of
Equipment
Process Type
ss
Electroless Copper, non-conveyorized
(BASELINE)
Electroless Copper, conveyorized
Carbon, conveyorized
Conductive Polymer, conveyorized
Graphite, conveyorized
Non-Formaldehyde Electroless Copper,
non-conveyorized
Organic-Palladium, non-conveyorized
Organic-Palladium, conveyorized
Tin-Palladium, non-conveyorized
Tin-Palladium, conveyorized
Function of Equipment*
Conveyor
0
1
1
1
1
0
0
1
0
1
Satfc
Heat
4
5
2
2
1
5
3
3
3
3
Fluid
Circulation
2
7
6
4
4
2
3
7
3
9
Air
Sparging1*
1
0
0
0
0
0
0
0
1
0
Panel i
Agitation'
1
0
0
0
0
1
1
0
1
0
Panel
Drying
0
0
2
0
1
0
0
0
0
0
Table entries for each MHC alternative represent the number of process baths requiring each specific function.
All functions are supplied by electric equipment, except for drying, which is performed by gas-fired oven.
b Air sparging is used selectively by some manufacturers to enhance bath performance. Sparging may not be
required for all product lines or facilities using an alternative.
c Processes reporting panel agitation for one or more baths are entered as one in the summary regardless of the
number since a single motor can provide agitation for the entire process line.
The electrical energy consumption of MHC line equipment as well as equipment
specifications (power rating, average duty, and operating load), were collected during the
Performance Demonstration. In cases where electricity consumption data were not available, the
electricity consumption rate was calculated using the following equation and equipment
specifications:
EC = NPR x OL x AD x (lkW/0.746 HP)
where:
EC
NPR
OL
AD =
= electricity consumption rate (kWh/day)
= nominal power rating (HP)
= operating load (%), or the percentage of the maximum load or output of
the equipment that is being used
tne equipment tnat is oemg usea
average duty (h/day), or the amount of time per day that the equipment is
being operated at the operating load
Electricity consumption data for each equipment category were averaged to determine the
average amount of electricity consumed per hour of operation for each type of equipment per
process. The natural gas consumption rate for a drying oven was supplied by an equipment
vendor. Electricity and natural gas consumption rates for MHC equipment per process stage are
presented in Table 5.6.
DRAFT
5-11
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5.2 ENERGY IMPACTS
Table 5.6 Energy Consumption Rates for MHC Equipment
Function of Equipment
Conveyorized Automation
Non-Conveyorized Process Line6
Heat
Fluid Circulation
Air Sparging
Drying Oven
Type of Equipment
Conveyor System
Panel Agitation Motor
Immersion Heater
Fluid Pump
Air Pump
Gas Heater
Energy Consumption Rates Per
. Process Stage
Electricity"
(kW/hr)
14.1
3.1
4.8
0.7
3.5
-
Natural <3asfr
(frVhr)
-
-
-
-
-
90
Electricity consumption rates for each type of equipment were calculated by averaging energy consumption data
per stage from the performance demonstrations. If required, consumption data were calculated from device
specifications and converted to total kW/hr per bath using 1 HP = 0.746 kW.
b Natural gas consumption rate for the gas heater was estimated by an equipment vendor (Exair Corp.).
c Non-conveyorized process lines are assumed to be manually operated with no automated panel transport system.
The electricity consumption rate reported includes the electricity consumed by a panel agitation motor.
The total electricity consumption rate for each MHC alternative was calculated by
multiplying the number of process stages that consume electricity (Table 5.5) by the appropriate
electricity consumption rate (Table 5.6) for each equipment category, then summing the results.
The calculations are described by the following equation:
n
ECRtl
,olal
= £
[NPSixECRi]
where:
ECR,ota]
NPSj
ECRr
= total electricity consumption rate (kW/h)
= number of process stages requiring equipment i
= energy consumption rate for equipment i (kW/h)
Natural gas consumption rates were calculated using a similar method. The individual
energy consumption rates for both natural gas and electricity were then converted to British
Thermal Units (Btu) per hour and summed for each alternative to give the total energy
consumption rate for each MHC alternative. The individual consumption rates for both natural
gas and electricity, as well as the hourly energy consumption rate calculated for each of the MHC
process alternatives are listed in Table 5.7.
DRAFT
5-12
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5.2 ENERGY IMPACTS
Table 5.7 Hourly Energy Consumption Rates for MHC Alternatives
Process Type
Electroless Copper, non-conveyorized (BASELINE)
Electroless Copper, conveyorized
Carbon, conveyorized
Conductive Polymer, conveyorized
Graphite, conveyorized
Non-Formaldehyde Electroless Copper, non-conveyorized
Organic-Palladium, non-conveyorized
Organic-Palladium, conveyorized
Tin-Palladium, non-conveyorized
Tin-Palladium, conveyorized
Energy Consumption
Bates
Electricity
(kW/hr)
27.2
^43
27.2
26.5
21.7
28.5
19.6
33.4
23.1
34.8
Natural Gas
CftVfcr)
-
-
180
-
90
-
-
-
-
-
Hourly
Consumption i
Rate*
(Bttt/fcr)
92,830
146,750
276,430
90,440
165,860
97,270
66,890
113,990
78,840
118,770
Electrical energy was converted at the rate of 3,413 Btu per kilowatt hour where a kWh = 1 kW/hr. Natural gas
consumption was converted at the rate of 1,020 Btu per cubic feet of gas consumed.
These energy consumption rates only consider the types of equipment listed in Table 5.4,
which are commonly recommended by chemical suppliers to successfully operate an MHC
process. However, equipment such as ultrasonics, automated chemical feed pumps, vibration
units, panel feed systems, or other types of electrically powered equipment may be part of the
MHC process line. The use of this equipment may improve the performance of the MHC line,
but is not required in a typical process for any of the MHC technologies.
To determine the overall amount of energy consumed by each technology, the hourly
energy consumption rate from Table 5.7 was multiplied by the amount of time needed for each
alternative to manufacture 350,000 ssf of board (the average MHC throughput of respondents to
the Workplace Practices Survey). Because insufficient survey data exist to accurately estimate
the amount of time required for each process to produce the 350,000 ssf of board, the operating
time was simulated using a computer model developed for each alternative. The results of the
simulation along with a discussion of the data and parameters used to define each alternative are
presented in Section 4.2, Cost Analysis. The hours of MHC operation required to produce
350,000 ssf of board from the simulation, the total amount of energy consumed, and the energy
consumption rate for each alternative per ssf of board produced are presented in Table 5.8.
Table 5.8 shows that all of the alternatives are more energy efficient than the traditional
non-conveyorized electroless copper process. This is primarily attributable to a process
operating time for non-conveyorized electroless copper that is two to eight times greater than the
operating times of the alternatives. Other processes with high energy consumption rates include
non-formaldehyde electroless copper due to its long operating time and both carbon and graphite
due to their high hourly consumption rates. The three processes consuming the least energy per
unit of production are the organic-palladium non-conveyorized system and the conductive
polymer and tin-palladium conveyorized systems.
DRAFT
5-13
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5.2 ENERGY IMPACTS
Table 5.8 Energy Consumption Rate per ssf of Board Produced for MHC Alternatives
Process Type
Electroless Copper, non-conveyorized (BASELINE)
Electroless Copper, conveyorized
Carbon, conveyorized
Conductive Polymer, conveyor ized
Graphite, conveyorized
Non-Formaldehyde Electroless Copper, non-conveyorized
Organic-Palladium, non-conveyorized
Organic-Palladium, conveyorized
Tin-Palladium, non-conveyorized
Tin-Palladium, conveyorized
Process
Operating
Time9
(hours)
2,160
329
650
367
450
971
350
456
581
284
Total
Energy
Consumed
(Bta/350,000 »sf)
2.01 x 108
4.83 x 107
l.SOxlO8
3.31xl07
7.46 x 107
9.44 x 107
2.34 x 107
5.19 xlO7
4.58 x 107
3.38 xlO7
Ensrgy i
Consumption;
Rate
(Bfoi/ss#
573
138
514
94.7
213
270
66.9
148
131
96.4
* Times listed represent the operating time required to manufacture 350,000 ssf of board by each process as
simulated by computer model.
The performance of specific MHC processes with respect to energy is primarily
dependent on the hourly energy consumption rate (Table 5.7) and the overall operating time for
the process (Table 5.8). Non-conveyorized processes typically have lower hourly consumption
rates than conveyorized processes because the operation of conveyorized equipment is more
energy-intensive. Although conveyorized processes typically have higher hourly consumption
rates, these differences are more than offset by the shorter operating times that are required to
produce an equivalent quantity of PWBs.
When MHC processes with both non-conveyorized and conveyorized versions are
compared, the conveyorized versions of the alternatives are typically more energy efficient.
Table 5.8 shows this to be true for both the electroless copper and tin-palladium processes. The
organic-palladium processes are the exceptions. The non-conveyorized configuration of this
process not only has a better hourly consumption rate than the conveyorized, but also benefits
from a faster operating time, a condition due to the low number of process baths and its short
rate-limiting step.1 These factors combine to give the non-conveyorized organic-palladium
process a lower energy consumption rate than the conveyorized version and make it the most
energy efficient process evaluated.
Finally, it should be noted that the overall energy use experienced by a facility will
depend greatly upon the operating practices and the energy conservation measures adopted by
that facility. To minimize energy use, several simple energy conservation opportunities are
available and should be implemented. These include insulating heated process baths, using
thermostats on heaters, and turning off equipment when not in use.
1 The rate-limiting step is the process step that requires more time than the other steps, thus limiting the
feed rate for the system.
DRAFT
5-14
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5.2 ENERGY IMPACTS
5.2.2 Energy Consumption Environmental Impacts
The production of energy results in the release of pollution into the environment,
including pollutants such as carbon dioxide (CO2), sulfur oxides (SO*), carbon monoxide (CO),
sulfuric acid (H2SO4), and particulate matter. The type and quantity of pollution depends on the
method of energy production. Typical energy production facilities hi the U.S. include
hydroelectric, nuclear, and coal-fired generating plants.
The environmental impacts attributable to energy production resulting from the
differences in energy consumption among MHC alternatives were evaluated using a computer
program developed by EPA National Risk Management Research Laboratory called P2P-
version 1.50214 (EPA, 1994). This program can, among other things, estimate the type and
quantity of pollutant releases resulting from the production of energy as long as the differences hi
energy consumption and the source of the energy used (i.e., does the energy come from a coal-
fired generating plant, or is it thermal energy from a oil-fired boiler, etc.) are known. The
program uses data reflecting the "national average" pollution releases per kilowatt-hour derived
from particular sources. Electrical power derived from the average national power grid was
selected as the source of electrical energy, while natural gas was used as the source of thermal
energy for this evaluation. Energy consumption rates from Table 5.7 were multiplied by the
operating time required to produce 350,000 ssf of board reported for each alternative in Table
5.8. These totals were then divided by 350,000 to get the electrical and thermal energy
consumed per ssf of board, which were then used as the basis for the analysis. Results of the
environmental impact analysis from energy production have been summarized and are presented
in Table 5.9. Appendix H contains printouts from the P2P program for each alternative.
Although the pollutant releases reported in Table 5.9 are combined for all media (i.e. air,
water, and land), they often occur in one or more media where they may present different hazards
to human health or the environment. To allow a comparison of the relative effects of any
pollution that may occur, it is necessary to identify the media of releases. Table 5.10 displays the
pollutants released during the production of energy, the media into which they are released, and
the environmental and human health concerns associated with each pollutant.
The information presented in Tables 5.9 and 5.10 show that the generation of energy is
not without environmental consequences. Pollutants released to air, water, and soil resulting
from energy generation can pose direct threats to both human health and the environment. As
such the consumption of energy by the MHC process contributes directly to the type and
magnitude of these pollutant releases. Primary pollutants released from the production of
electricity include carbon dioxide, solid wastes, sulfur oxides and nitrogen oxides. These
pollutants contribute to a wide range of environmental and human health concerns. Natural gas
consumption results primarily in releases of carbon dioxide and hydrocarbons which typically
contribute to environmental problems such as global warming and smog. Because all of the
MHC alternatives consume less energy than the traditional non-conveyorized electroless copper
process, they all decrease the quantity of pollutants released into the environment resulting from
the generation of the energy consumed during the MHC process.
DRAFT
5-15
-------
5.2 ENERGY IMPACTS
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5.2 ENERGY IMPACTS
Table 5.10 Pollutant Environmental and Human Health Concerns
Pollutant
Carbon Dioxide (CO2)
Carbon Monoxide (CO)
Dissolved Solids
Hydrocarbons
Nitrogen Oxides (NOJ
Particulates
Solid Wastes
Sulfur Oxides (SOX)
Sulfuric Acid (H2SO4)
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Particulates0
Land disposal capacity
Toxic inorganic/ acid rain, corrosive
Corrosive, dissolved solids'5
Toxic organic and inorganic pollutants can result in adverse health effects in humans and wildlife.
b Dissolved solids are a measure of water purity and can negatively affect aquatic life as well as the future use of the
water (e.g., salinity can affect the water's effectiveness at crop irrigation).
0 Particulate releases can promote respiratory illness in humans.
5.2.3 Energy Consumption in Other Life-Cycle Stages
When performing a comparative evaluation among MHC technologies, the energy
consumed throughout the entire life cycle of the chemical products in the technology should be
considered. The product use phase is only one aspect of the environmental performance of a
product. A life-cycle analysis considers all stages of the life of a product, beginning with the
extraction of raw materials from the environment, and continuing on through the manufacture,
transportation, use, recycle, and ultimate disposal of the product.
Each stage within this life cycle consumes energy. It is possible for a product to be
energy efficient during the use phase of the life cycle, yet require large amounts of energy to
manufacture or dispose of the product. The manufacture of graphite is an example of an energy-
intensive manufacturing process. Graphite is manufactured by firing carbon black particles to
temperatures over 3000 °F for several hours, which is required to give a crystalline structure to
the otherwise amorphic carbon black particles (Thorn, 1996). There are also energy consumption
differences in the transportation of wastes generated by an MHC line. The transportation of large
quantities of sludge resulting from the treatment of processes with chelated waste streams (i.e.,
electroless copper), will consume more energy than the transportation of smaller quantities of
sludge resulting from processes that do not use chelators. These examples show that energy use
from other life-cycle stages can be significant and should be considered when evaluating the .
energy performance of a product. However, a comprehensive assessment of other life-cycle
stages was beyond the scope of this study.
5.2.4 Conclusions
A comparative analysis of the relative energy consumption rates was performed for the
MHC technologies. An hourly energy consumption rate was developed for the baseline and each
alternative using data collected from industry through a survey. A computer simulation was used
DRAFT
5-17
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5.2 ENERGY IMPACTS
to determine the operating time required to produce 350,000 ssf of PWB and an energy
consumption rate per ssf of PWB was calculated. The energy consumption rates ranged from
66.9 Btu/ssf for the non-conveyorized organic-palladium process to 573 Btu/ssf for the non-
conveyorized electroless copper process. The results indicate all of the MHC alternatives are
more energy efficient than the traditional non-conveyorized electroless copper process. It was
also found that for alternatives with both types of automation, the conveyorized version of the
process is typically the more energy efficient, with the notable exception of the organic-
palladium process.
An analysis of the impacts directly resulting from the production of energy consumed by
the MHC process showed that the generation of the required energy is not without environmental
consequence. Pollutants released to air, water, and soil can result in damage to both human
health and the environment. The consumption of natural gas tends to result in releases to the air
which contribute to odor, smog, and global warming, while the generation of electricity can
result in pollutant releases to all media with a wide range of possible affects. Since all of the
MHC alternatives consume less energy than electroless copper they all result in less pollutant
releases to the environment from energy production.
DRAFT
5-18
-------
REFERENCES
REFERENCES
City of San Jose, California. 1996. "Direct Metallization Report-Draft." Environmental
Services Dept. June.
Thorn, Ed. Electrochemicals. 1996. Personal communication with Jack Geibig, UTCenter for
Clean Products and Clean Technologies. March 18.
U.S. Environmental Protection Agency. 1994. P2P-Version 1.50214 computer software
program. Office of Research and Development, National Risk Management Research
Laboratory, Cincinnati, OH. 1994.
DRAFT
5-19
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-------
Chapter 6
Additional Environmental Improvement Opportunities
This chapter of the Cleaner Technologies Substitute Assessment (CTSA) identifies and
qualitatively discusses techniques that can be used by printed wiring board (PWB) manufacturing
facilities to prevent pollution, minimize waste, recycle and recover valuable resources, and
control releases. The Pollution Prevention Act of 1990, set forth the following hierarchy to
waste management in order of desirability:
• Pollution prevention at the source.
• Recycling in an environmentally safe manner.
• Treatment in an environmentally safe manner.
• Disposal or other release into the environment only as a last resort and in an
environmentally safe manner.
This hierarchy has been adopted by EPA as the preferred method of waste management to
reduce or eliminate potential releases by industry. The hierarchy reflects the common sense
notion that preventing pollution is preferable to any subsequent response, be it recycling,
treatment, or disposal. By preventing pollution we also eliminate potential transfers of the
pollution across media (Kling, 1995).
The hierarchy also recognizes that pollution prevention is not always feasible and that
other waste management methods are often required. When pollution prevention is not feasible,
we should turn in order to recycling, treatment, and finally disposal if no other option remains.
A manufacturing facility often combines pollution prevention techniques with these other
approaches to effectively reduce emissions from a production process. While pollution
prevention is clearly the most desirable, all of these methods contribute to overall environmental
improvement (Kling, 1995).
This chapter focuses on the application of the waste management hierarchy to potential
waste streams generated by the making holes conductive (MHC) process of the PWB industry.
Techniques are identified, organized, and presented in an order corresponding to the hierarchy.
Pollution prevention techniques are presented in Section 6.1, while methods for minimizing
waste, recycling or recovering resources, and controlling releases are presented in Section 6.2.
While the focus of this chapter is on the MHC line, many of the techniques described here can be
applied to other processes used in PWB manufacturing. A series of pollution prevention case
studies developed by the EPA DfE Program for the PWB industry present examples of the
successful implementation of techniques available to industry (EPA, 1995a; EPA 1995b; EPA,
1996a; EPA 1996b; EPA 1996c).
DRAFT
6-1
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6.1 POLLUTION PREVENTION
6.1 POLLUTION PREVENTION
Pollution prevention, defined in the Pollution Prevention Act of 1990, is the reduction in
the amounts or hazards of pollution at the source and is often referred to as source reduction.
Source reduction, also defined in the Pollution Prevention Act, is any practice which: 1) reduces
the amount of any hazardous substance, pollutant, or contaminant entering any waste stream or
otherwise released into the. environment (including fugitive emissions) prior to recycling,
treatment, or disposal; and 2) reduces the hazards to public health and the environment
associated with the release of such substances, pollutants, or contaminants. Source reduction
includes equipment or technology modification, process or procedure modifications,
reformulation or redesign of products, substitution of raw materials, and improvements in
housekeeping, maintenance, training, or inventory control.
Current pollution prevention practices within the PWB industry were identified and data
were collected through contact with industry personnel, extensive review of published accounts,
and through the design and dissemination of two industry surveys of PWB manufacturers. The
Workplace Practices Survey, conducted as part of this CTSA, specifically focused on the MHC
process to identify important process parameters and operating practices for the various MHC
technologies. For a breakdown of survey respondents by alternative, refer to Section 1.3.4 of the
Introduction. Facility characteristics of survey respondents are presented in Section 3.2,
Exposure Assessment. The questionnaire used in the Workplace Practices Survey is presented in
Appendix A.
The Pollution Prevention and Control Technology Survey (hereafter referred to as the
Pollution Prevention Survey) was designed to collect information about past and present
pollution prevention procedures and control technologies for the entire PWB manufacturing
process. This Survey was performed by the DfE PWB Project and is documented in the EPA
publication, Printed Wiring Board Pollution Prevention and Control: Analysis of Survey Results
(EPA, 1995c). The survey results presented periodically throughout this chapter are compiled
from responses to the Pollution Prevention Survey unless otherwise indicated. Results from the
Pollution Prevention Survey pertaining to recycle or control technologies are presented in
Section 6.2 of this chapter.
Opportunities for pollution prevention in PWB manufacturing were identified in each of
the following areas:
• Management and personnel practices.
• Materials management and inventory control.
• Process improvements.
The successful implementation of pollution prevention practices can lead to reductions in
waste treatment, pollution control, environmental compliance, and liability costs. Cost savings
can result directly from pollution prevention techniques that minimize water usage, chemical
consumption, and process waste generation.
DRAFT
6-2
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6.1 POLLUTION PREVENTION
6.1.1 Management and Personnel Practices
Pollution prevention is an ongoing activity that requires the efforts of both management
and employees to achieve the best results. While management's commitment to reducing
pollution is the foundation upon which a successful pollution prevention program is built, any
pollution prevention measures taken are ultimately implemented by the process employees,
making them an integral part of any pollution prevention effort. Management and employees
must work together to form an effective pollution prevention program.
Approximately half (52.6 percent) of the PWB companies responding to the Pollution
Prevention Survey reported having a formal pollution prevention policy statement while half (50
percent) of the survey respondents reported having a pollution prevention program. Over two
thirds (68.4 percent) of PWB companies surveyed reported conducting employee education for
pollution prevention.
The scope and depth of pollution prevention planning and the associated activities will
vary with the size of the facility. While larger facilities may go through an entire pollution
prevention planning exercise (as described below), smaller facilities may require as little as a
commitment by the owner to pollution prevention along with cooperation and assistance from
employees to meet any stated goals. A list of management and personnel practices that promote
pollution prevention, along with their benefits, are listed in Table 6.1.
Table 6.1 Management and Personnel Practices Promoting Pollution Prevention
--' Method
Create a company pollution prevention and waste
reduction policy statement.
Develop a written pollution prevention and waste
reduction plan.
Provide periodic employee training on pollution
prevention.
Make employees accountable for their pollution
prevention performance and provide feedback on
their performance.
Promote internal communication between
management and employees.
Implement total cost accounting or activity-based
accounting system.
Benefits
Communicates to employees and states publicly the
company commitment to achieving pollution
prevention and waste reduction goals.
Communicates to employees how to accomplish the
goals identified in the company's policy statement.
Identifies in writing specific implementation steps
for pollution prevention.
Educates employees on pollution prevention
practices.
Provides incentives to employees to improve
pollution prevention performance.
Informs employees and facilitates input on pollution
prevention from all levels of the company.
Identifies true costs of waste generation and the
benefits of pollution prevention.
A company's commitment to pollution prevention begins with a pollution prevention and
waste reduction policy statement. This statement, which is the company's public proclamation
of its dedication to preventing pollution and reducing waste, should clearly state why a program
is being undertaken, include specific pollution prevention and waste reduction goals, and assign
responsibility for accomplishing those goals. The statement details to the public and to its
employees the depth of the company's commitment to pollution prevention.
DRAFT
DRAFT
6-3
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6.1 POLLUTION PREVENTION
A pollution prevention plan is needed to detail how the pollution prevention and waste
reduction goals described in the company's policy statement will be achieved. The pollution
prevention plan builds on the company's policy statement by:
• Creating a list of waste streams and their point sources.
• Identifying opportunities for pollution prevention.
• Evaluating and prioritizing waste reduction options.
• Developing an implementation strategy for options that are feasible.
• Creating a timetable for pollution prevention implementation.
• Detailing a plan for measuring and evaluating pollution prevention and waste reduction
progress.
The plan is best developed with input drawn from the experiences of a team of people
selected from levels throughout the company. The team approach provides a variety of
perspectives to pollution prevention and helps to identify pollution prevention opportunities and
methods for implementing them. Team members should include representatives from
management, supervisory personnel, and line workers who are familiar with the details of the
daily operation of the process. The direct participation of employees in the development of the
pollution prevention plan is important since it is the employees who are responsible for
implementing the plan.
Data should be collected by performing a waste minimization assessment on the
company or process being targeted. Once identified, pollution prevention options should be
evaluated and prioritized based on their cost, feasibility of implementation, and their overall
effectiveness of reducing waste. After an implementation strategy and timetable is established,
the plan, along with expected benefits, should be presented to the remaining company employees
to communicate the company's commitment to pollution prevention.
Once the pollution prevention plan has been finalized and implementation is ready to
begin, employees must be given the skills to implement the plan. Training programs play an
important role in educating process employees about current pollution prevention practices and
opportunities. The goal of the training program is to educate each employee on how waste is
generated, its effects on worker safety and the environment, possible methods for waste
reduction, and on the overall benefits of pollution prevention.
Employee training should begin at the time of new employee orientation, introducing
them to the company's pollution prevention plan, thus highlighting the company's dedication to
reducing waste. More advanced training focusing on process operating procedures, potential
sources of release, and pollution prevention practices already in place should be provided after a
few weeks of work or when an employee starts a new position. Retraining employees
periodically will keep them focused on the company's goal of pollution prevention.
Effective communication between management and employees is an important part of a
successful pollution prevention program. Reports to employees on the progress of implementing
pollution prevention recommendations, as well as the results of actions already taken, reiterate
DRAFT
6-4
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6.1 POLLUTION PREVENTION
management's commitment to reducing waste, while keeping employees informed and intimately
involved in the process. Employee input should also be solicited both during and after the
creation of the pollution prevention plan to determine if any changes hi the plan are warranted.
Assigning responsibility for each source of waste is an important step hi closing the
pollution prevention loop. Making individual employees and management accountable for
chemical usage and waste generated within their process or department provides incentive for
employees to reduce waste. The quantity of waste generated should be tracked and the results
reported to employees who are accountable for the process generating the waste. Progress hi
pollution prevention should be an objective upon which employees will be evaluated during
performance reviews, once again emphasizing the company's commitment to waste reduction.
Employee initiative and good performance in pollution prevention areas should be
recognized and rewarded. Employee suggestions that prove feasible and cost effective should be
implemented and the employee recognized either with a company commendation or with some
kind of material award. These actions will ensure continued employee participation in the
company's pollution prevention efforts.
Implementing an activity-based or total cost accounting system will identify the costs of
waste generation that are typically hidden hi overhead costs by standard accounting systems.
These cost accounting methods identify cost drivers (activities) within the manufacturing process
and assign the costs incurred through the operation of the process to the cost drivers. By
identifying the cost drivers, manufacturers can correctly assess the true cost of waste generation
and the benefits of any pollution prevention efforts.
6.1.2 Materials Management and Inventory Control
Materials management and inventory control focuses on how chemicals and materials
flow through a facility in order to identify opportunities for pollution prevention. A proper
materials management and inventory control program is a simple, cost-effective approach to
preventing pollution. Table 6.2 presents materials management and inventory control methods
that can be used to prevent pollution.
Table 6.2 Materials Management and Inventory Control Pollution Prevention Practices
Practice
Minimize the amount of chemicals kept on the
floor at one time.
Manage inventory on a first-in, first-out basis.
Centralize responsibility for storing and
distributing chemicals.
Store chemical products in closed, clearly marked
containers.
Use a pump to transfer chemical products from
stock to transportation container.
Benefits
Provides incentives to employees to use less
chemicals.
Reduces materials and disposal costs of expired
chemicals.
Provides incentives to employees to use less
chemicals.
Reduces materials loss; increases worker safety by
reducing worker exposure.
Reduces potential for accidental spills; reduces
worker exposure.
DRAFT
DRAFT
6-5
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6.1 POLLUTION PREVENTION
Controlling inventory levels and limiting access to inventory are widely used practices in
the PWB manufacturing industry (78.9 percent of Pollution Prevention Survey respondents).
Keeping track of chemical usage and limiting the amount of chemicals on the process floor
provides process operators an incentive to use the minimum quantity of chemical required to do
the job. Using chemicals on a first-in/first-out basis reduces the time chemicals spend in storage
and the amount of expired chemical that is disposed. Some companies have contracted with a
specific chemical supplier to provide all of their process chemicals and manage their inventory.
In exchange for the exclusive contract, the chemical supplier assumes many of the inventory
management duties including managing the inventory, material safety data sheets (MSDSs),
ordering the chemicals, distributing the chemicals throughout the plant, and disposing of spent
chemicals and packaging (Brooman, 1996).
Chemical storage and handling practices also provide pollution prevention opportunities.
Ensuring that all chemical containers are kept closed when not in use minimizes the amount of
chemical lost through evaporation or volatilization. When transferring chemicals from container
to container, utilizing a hand pump can reduce the amount of chemical spillage. These simple
techniques not only result in less chemical usage representing a cost savings, but also result in
reduced worker exposure and an improved worker environment.
6.1.3 Process Improvements
Improving the efficiency of a production process can significantly reduce waste
generation at the source. Process improvements include process or procedural changes in
operations carried out by employees, process equipment modification or automation, and
redesign of the process altogether. Process improvements that lead to pollution prevention in the
MHC process are categorized by the following goals:
• Extend chemical bath life.
• Reduce water consumption.
• Improve process efficiency through automation.
Pollution prevention through process improvement does not always have to be expensive.
In fact, some of the most cost-effective pollution prevention techniques are simple, inexpensive
changes in production procedures. Process improvements that help achieve the goals listed
above, along with their benefits, are discussed in detail in the sections below.
Extend Chemical Bath Life
The MHC process involves the extensive use of chemicals, many of which are costly and
pose a hazard to human health and the environment. Improvements in the efficient usage of
these chemicals can occur by accomplishing the following:
• Reducing chemical bath contamination.
• Reducing chemical bath drag-out.
• Improving bath maintenance.
DRAFT
6-6
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6.1 POLLUTION PREVENTION
Inefficiencies in the use of chemicals can result in increased chemical usage, higher
operating costs, increased releases to the environment, and increased worker exposure.
Techniques to improve the efficient use of chemicals by the MHC and other PWB process steps
are discussed in detail below.
Reduce Bath Contaminants. The introduction of contaminants to a chemical bath will
affect its performance and significantly shorten the life of the chemical bath. Bath contaminants
include chemicals dragged-in from previous chemical baths, chemical reaction by-products, and
particulate matter which may be introduced to the bath from the air. Process baths are replaced
when impurities reach a level where they degrade product quality to an unacceptable level. Any
measure that prevents the introduction of Impurities will not only result in better bath
performance, but also will reduce chemical usage and generate less waste. Table 6.3 presents
pollution prevention methods for reducing bath contamination.
Table 6.3 Pollution Prevention Practices to Reduce Bath Contaminants
Practices
Improve the efficiency of the water rinse system.
Use distilled or deionized water during chemical
bath make-up.
Maintain and rebuild panel racks.
Clean process tanks efficiently before new bath
make-up.
Utilize chemical bath covers when process baths
are not in operation.
Filter contaminants continuously from process
baths.
Benefits ,
Rinses off any residual bath chemistries and
dislodges any particulate matter from panels and
racks.
Reduces chemical contamination resulting from
water impurities.
Prevents the build-up of deposits and corrosion that
can dislodge or dissolve into chemical baths.
Prevents contamination of the new bath from
residual spent bath chemistries.
Reduces the introduction of unwanted airborne
particulate matter; prevents evaporation or
volatilization of bath chemistries.
Prevents the build-up of any contaminants.
Thorough and efficient water rinsing of process panels and the racks that carry them is
crucial to preventing harmful chemical drag-in and to prolonging the life span of the chemical
baths. The results of the Workplace Practices Survey indicate that nearly every chemical bath in
the MHC process is preceded by at least one water rinse tank. Improved rinsing can be achieved
by using spray rinses, panel and/or water agitation, warm water, or by several other methods that
do not require the use of a greater volume of water. A more detailed discussion of these methods
is presented in the reduced water consumption portion in this section.
A rack maintenance program is also an important part of reducing chemical bath
contamination and is practiced by 87 percent of the respondents to the Pollution Prevention
Survey. By cleaning panel racks regularly and replacing corroded metal parts, preferably with
parts of plastic or stainless steel, chemical deposition and build-up can be minimized.
Respondents to the Workplace Practices Survey typically perform rack cleaning using a chemical
solution, usually acid. Mechanical methods, such as peeling or filing away the majority of any
metal deposits before applying a weak acid solution, can be used to prevent pollution by reducing
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the quantity of acid required. An added benefit is that the reclaimed metal can be sold or reused
in the process.
According to the Workplace Practices Survey, 42 percent of the respondents reported
using bath covers on at least some of their baths during periods when the MHC process was not
operating. Respondents were not specifically questioned about the other methods for reducing
bath contamination described above; consequently, no information was collected.
Chemical Bath Drag-Out Reduction. The primary loss of bath chemicals during the
operation of the MHC process comes from chemical bath drag-out (Bayes, 1996). This loss
occurs as the rack full of panels is being removed from the bath, dragging with it a film of
chemical solution still coating the panels. The drag-out is then typically rinsed from the panels
by a water rinse tank, making bath drag-out the primary source of chemical contaminant
introduction into the MHC rinse water. In some cases, however, the panels are deposited directly
into the next process bath without first being rinsed (e.g., predip followed directly by palladium
catalyst in tin-palladium process).
Techniques that minimize bath drag-out also prevent the premature reduction of bath
chemical concentration, extending the useful life of a bath. In addition to extended bath life,
minimizing or recovering drag-out losses also has the following effects:
• Requires less rinse water.
• Minimizes bath chemical usage.
* Reduces chemical waste.
• Requires less water treatment chemical usage.
Methods for reducing or recovering chemical bath drag-out are presented in Table 6.4 and
then discussed below.
The most common methods of drag-out control employed by respondents to the Pollution
Prevention Survey are slow panel removal from the bath (52.6 percent) and increased panel
drainage time (76.3 percent). Removing the panels slowly from the bath allows the surface
tension of the solution to remove much of the residual chemical from the panels. Most of the
remaining chemicals can be removed from the panel surfaces by increasing the time allowed for
the panels to drain over the process bath. Briefly agitating the panels directly after being
removed from the tank can also help dislodge chemicals trapped in panel through-holes and
result in better drainage. All three methods require no capital investment and when practiced
individually or in combination, these techniques are effective methods for reducing drag-out.
Drain boards catch drag-out chemicals that drip from panels as they are transported to the
next process step. The chemicals are then returned to the original process bath. Chemical loss
due to splashing can be prevented by the use of drip shields, which are plastic panels that extend
the wall height of the process tank. Both drain boards and drip shields are inexpensive, effective
drag-out control options. Unlike drip shields, however, space between process steps is required
to install drain boards, making them unpractical where process space is an issue.
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Table 6.4 Methods for Reducing Chemical Bath Drag-Out
Methods
Remove panels slowly from process baths.
Increase panel drainage time over process bath.
Agitate panels briefly while draining.
Install drain boards.
Install drip shields between process baths.
Add static drag-out tanks/drip tanks to process line
where needed.
Utilize non-ionic wetting agents in the process bath
chemistries.
Utilize air knives directly after process bath in
conveyorized system."
Decrease process bath viscosity.
Employ fog rinses/spray rinses over heated baths.
Benefits
Reduces the quantity of residual chemical on panel
surfaces.
Allows a greater volume of residual bath
chemistries to drip from the panel back into the
process bath.
Dislodges trapped bath chemistries from drilled
through-holes.
Collects and returns drag-out to process baths.
Prevents bath chemical loss due to splashing.
Recovers chemical drag-out for use in bath
replenishment.
Reduces surface tension of bath solutions, thereby
reducing residual chemicals on panel surfaces.
Blows residual process chemistries from process
panels which are recaptured and returned to
process bath.
Reduces quantity of chemical that adheres to panel
surface.
Rinses drag-out from the panels as they are
removed from the solution.
a May not be a viable pollution prevention technique unless system is fully enclosed to prevent worker exposure to
bath chemicals introduced to the air.
Much of the chemical solution lost to drag-out can be recovered through the use of either
static drag-out tanks or drip tanks. A static drag-out tank is a batch water bath that immediately
follows the process bath from which the drag-out occurs. The panels are submerged and agitated
in the static rinse water, washing the residual chemicals from the panels' surface. When
sufficiently concentrated, the rinse water and chemical mixture can be used to replenish the
original bath. Drip tanks are similar to static drag-out tanks except that they contain no water.
The drip tank collects chemical drag-out which can then be returned to the process bath. Static
drag-out tanks are most suitably used in conjunction with heated process baths which lose water
by evaporation, requiring frequent replacement.
Bath viscosity can be lowered by increasing bath temperature, decreasing bath
concentration, or both. Both of these methods may negatively affect overall process performance
if done in excess, however, and the chemical supplier should be consulted. In addition, increased
bath temperatures can increase chemical volatilization and worker exposure. Energy
implications of higher temperature baths should also be considered and are discussed in Section
5.2.
Bath Maintenance Improvements. The MHC process and other wet chemistry
processes in PWB manufacturing are series of complex, carefully balanced and formulated
chemical mixtures, each one designed to operate at specific conditions, working together to
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perform an overall function. A bath testing and control program is essential in preventing the
chemical breakdown of process baths, thus extending their useful lives and preventing their
premature disposal. The premature disposal of process chemistries results hi increased chemical
costs for both bath and treatment chemicals, prolonged process down-time, and increased process
waste.
Bath maintenance, or control, refers to maintaining a process bath hi peak operating
condition by identifying and controlling key operating parameters, such as bath temperature,
individual chemical concentrations, pH, and the concentration of contaminants. Proper control
of bath operating parameters will result in more consistent bath operation, less water usage, and
better, more consistent quality of work.
According to Pollution Prevention Survey respondents, the majority of PWB
manufacturing facilities (92.1 percent) have a preventative bath maintenance program already in
place. Typical bath maintenance methods and their benefits are presented in Table 6.5 below.
Table 6.5 Bath Maintenance Improvement Methods To Extend Bath Life
Methods
Monitor bath chemistries by testing frequently.
Replace process baths according to chemical
testing.
Maintain operating chemical balance through
chemical additions according to testing.
Filter process baths continuously.
Employ steady state technologies.
Install automated/statistical process control system.
Utilize temperature control devices.
Utilize bath covers.
Benefits
Determines if process bath is operating within
recommended parameters.
Prevents premature chemical bath replacement of
good process baths.
Maintains recommended chemical concentrations
through periodic chemical replenishment as
required.
Prevents the build-up of harmful impurities that
may shorten bath life.
Maintains steady state operating conditions by
filtering precipitates or regenerating bath solutions
continuously.
Provides detailed analytical data of process
operating parameters, facilitating more efficient
process operation.
Regulates bath temperatures to maintain optimum
operating conditions.
Reduces process bath losses to evaporation and
volatilization.
Frequent monitoring and adjustment of the various chemical concentrations within a
process bath are the foundations on which a good bath maintenance program is built. Monitoring
is done by regularly testing the bath concentrations of key chemicals to ensure that the bath is
chemically balanced. If chemical concentrations are outside of the operating levels
recommended by the supplier, a volume of chemical is added to the bath to bring it back into
balance. When the concentration of contaminants reaches an established critical level, or some
other criteria reported by the supplier, the bath is disposed of and replaced with a new bath.
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Bath testing and adjustment can be performed manually or with an automated system that
can perform both functions. Either way, controlling the bath through regular testing and bath .
additions is an inexpensive, effective method for extending bath life and reducing pollution.
Nearly all of the PWB facilities surveyed (97.4 percent) report testing chemical bath
concentrations.
Bath replacement should be based upon chemical testing, instead of some other
predetermined criteria. Predetermined criteria, such as times or production volumes, are often
given by suppliers as safe guidelines for bath replacement for facilities that do not regularly test
their process baths. These criteria are conservative estimates of the effective life of the process
bath, but can be exceeded with a proper bath testing and maintenance program. By replacing the
process bath only when chemical testing indicates it is required, bath life can be extended while
chemical usage and waste are reduced. Most (92.1 percent) of the surveyed PWB facilities
reported replacing their process baths only when testing indicated.
The build-up of contaminants in a process bath will eventually require the bath to be
replaced. Bath contaminants can be solid matter, such as particulate matter and precipitates, or
undesired chemical species in solution, such as reaction byproducts or drag-in chemicals. An
effective method of extending bath life is to continuously filter the process bath to remove
undesired bath constituents. Installing standard cartridge or bag filters which remove solid
impurities from the bath is another inexpensive, yet effective method to extend bath life.
Some baths may be maintained at steady state conditions using readily obtainable
systems capable of regenerating or filtering process bath chemistries. For example, a system that
continuously filters the copper sulfate precipitate from peroxide-sulfuric microetch baths can be
used to maintain the microetch bath on a MHC process line, providing a recyclable precipitate.
Regeneration techniques can be used to continuously regenerate both alkaline and cupric chloride
etchants. Maintaining steady state conditions keeps a bath within the optimal operating
conditions resulting in extended bath life (Edwards, 1996).
Statistical process control (SPC) is a method of analyzing the current and past
performance of a process bath, using chemical testing results and operating condition records to
optimize future bath performance. SPC will lead to more efficient bath operation and extended
bath life by indicating when a bath needs maintenance through the tracking and analysis of
individual operating parameters and their effect on past performance (Fehrer, 1996). Only one
quarter (26.3 percent) of the survey respondents reported using a SPC system.
Many of the MHC process baths are heated, making temperature control an important
necessity for proper bath operation. If bath temperature is not controlled properly, the bath may
not be hot enough to perform its function, or may become too hot, leading to chemical and water
losses due to evaporation or volatilization. The bath chemicals that remain become more
concentrated, resulting in increased chemical loss to drag-out. By installing thermostats on all
heated process baths, solution temperature will be kept constant, reducing waste generation and
chemical and energy use, and saving money through decreased energy use, chemical use, and
waste treatment costs.
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Another method of limiting evaporative losses from process baths is to cover the surface
of the solution with floating plastic balls that will not react with the process solution. The plastic
balls, which do not interfere with the work pieces being processed, prevent the evaporation of the
bath solution by limiting the surface area of solution exposed to the air. One facility uses ping
pong balls which are made from polystyrene to minimize losses from the electroless copper bath.
Hexagonal-shaped balls are now available that leave even less surface area exposed to the air
(Brooman, 1996). This method is especially effective for higher temperature process baths
where evaporative losses tend to be high. This method is inexpensive, easy to utilize, and will
decrease the air emissions from the bath, limiting the amount of operator exposure to the
chemicals.
Reduced Water Consumption
Contaminated rinse water is the primary source of heavy metal ions discharged to waste
treatment processes from the MHC process and other wet chemistry process lines (Bayes, 1996).
These contaminants, which are introduced to the rinse water through chemical drag-out, must be
treated and removed from the water before it can be reused in the process or discharged to the
sewer. Because rinsing is often an uncontrolled portion of the process, large quantities of water
are consumed and treated unnecessarily. Reducing the amount of water used by the MHC
process has the following benefits:
Decreases water and sewage costs.
Reduces wastewater treatment requirements, resulting in less treatment chemical usage
and reduced operating costs.
Reduces the volume of sludge generated from wastewater treatment.
Improves opportunities to recover process chemicals from more concentrated waste
streams.
The MHC process line consists of a series of chemical baths, which are typically
separated by at least one, and sometimes more, water rinse steps. These water rinse steps
account for virtually all of the water used during the operation of the MHC line. The water baths
act as a buffer, dissolving or displacing any residual drag-in chemicals from the panels surface.
The rinse baths prevent contamination of subsequent baths while creating a clean surface for
future chemical activity.
Improper rinsing does not only lead to shortened bath life through increased drag-in, as
discussed previously, but can also lead to a host of problems affecting product quality, such as
peeling, blistering, and staining. Insufficient rinsing of panels can lead to increased chemical
drag-in quantities and will fail to provide a clean panel surface for subsequent chemical activity.
Excessive water rinsing, done by exposing the panels too long to water rinsing, can lead to
oxidation of the copper surface and may result in peeling, blistering, and staining. To avoid
insufficient rinsing, manufacturers often use greater water flow rates than are necessary, instead
of using more efficient rinsing methods that reduce water consumption but may be more
expensive to implement. These practices were found to be true among survey respondents,
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where facilities with low water and sewage costs typically used much larger amounts of water
than comparable facilities with high water and sewer costs.
Many techniques are available that can reduce the amount of water consumed while
rinsing. These techniques are categorized by the following:
• Methods to control water flow.
• Techniques to improve water rinse efficiency.
• Good housekeeping practices.
Flow control methods focus on controlling the flow of water, either by limiting the
maximum rate that water is allowed to flow into the rinse system, or by stopping and starting the
water flow as it is needed. These methods seek to limit the total water usage while ensuring that
sufficient water is made available to cleanse the PWB panels. Examples of these techniques
include the use of flow restrictors or smaller diameter piping to limit the maximum flow of
water, and control valves that provide water to the rinse baths only when it is needed. Control
valves can be either manually operated by an employee, or automated using some kind of sensing
device such as conductivity meters, pH meters, or parts sensors. All of the methods are effective
water reduction techniques that can be easily installed.
Pollution prevention techniques directed at improving water efficiency in the rinse system
seek to control or influence the physical interaction between the water and the panels. This can
be done by increasing bath turbulence, improving water quality, or by using a more efficient
rinse configuration. All of these methods, discussed below, seek to improve rinsing performance
while using less water.
Increasing bath turbulence can be accomplished through the use of ultrasonics, panel
agitation, or air sparging. All of these agitation methods create turbulence in the bath, increasing
contact between the water and the part, thereby accelerating the rate that residual chemicals are
removed from the surface. Agitating the bath also keeps the water volume well mixed,
distributing contaminants throughout the bath and preventing concentrations of contaminants
from becoming trapped. However, agitating the bath can also increase air emissions from the
bath unless pollution prevention measures are used to reduce air losses.
Water quality can be improved by using distilled or deionized water for rinsing instead of
tap water that may include impurities such as carbonate and phosphate precipitates, calcium,
fluoride, and iron. Finally, utilizing more efficient rinse configurations such as countercurrent
rinse stages, spray rinses, or fog rinses will increase the overall efficiency of the MHC rinse
system while reducing the volume of wastewater generated. PWB manufacturers often use
multiple rinse water stages between chemical process steps to facilitate better rinsing. The first
rinse stage removes the majority of residual chemicals and contaminants, while subsequent rinse
stages remove any remaining chemicals. Counter-current or cascade rinse systems minimize
water use by feeding the water effluent from the cleanest rinse tank, usually at the end of the
cascade, into the next cleanest rinse stage, and so on, until the effluent from the most
contaminated, initial rinse stage is sent for treatment or recycle.
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Good housekeeping practices focus on keeping the process equipment in good repair and
fixing or replacing leaky pipes, pumps, and hoses. These practices can also include installing
devices such as spring loaded hose nozzles that shut off when not in use, or water control timers
that shut off water flow in case of employee error. These practices often require little investment
and are effective in preventing unnecessary water usage. For a more detailed discussion on
methods of improving water rinse efficiency and reducing water consumption, refer to Section
5.1, Resource Conservation.
Improve Process Efficiency Through Automation
The operation of the MHC process presents several opportunities for important and
integral portions of the process to become automated. By automating important functions,
operator inconsistencies can be eliminated allowing the process to be operated more efficiently.
Automation can lead to the prevention of pollution by:
• Gaining a greater control of process operating parameters.
• Performing the automated function more consistently and efficiently.
• Eliminating operator errors.
• Making the process compatible with newer and cleaner processes designed to be operated
with an automated system.
Automating a part of the MHC process can be expensive. The purchase of some
automated equipment can require a significant initial investment, which may prevent small
companies from automating. Other costs that may be incurred include installing the equipment,
training employees, any lost production due to process down-time, and the cost of redesigning
other processes to be compatible with the new system. Although it may be expensive, the
benefits of automation on productivity and waste reduction will result in a more efficient process
that can save money over the long run.
Installation of automated equipment such as a rack or panel transportation system,
chemical sampling equipment, or an automated system to make chemical additions can have a
major impact on the quantity of pollution generated during the day-to-day operation of the MHC
process and can also reduce worker exposure. MHC process steps or functions that can be
automated effectively include:
• Rack transportation.
• Bath maintenance.
• Water flow control.
Rack transportation systems present an excellent opportunity for automation, due to the
repetitive nature of transporting panel racks. Various levels of automation are available ranging
from a manually operated vertical hoist to a computer controlled robotic arm. All of these
methods allow for greater process control over panel movement through the MHC process line.
By building in drag-out reduction methods such as slower panel withdraw and extended drainage
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times into the panel movement system, bath chemical loss and water contamination can be"
greatly reduced.
Automating bath maintenance testing and chemical additions can result in longer bath life
and reduced waste. These systems monitor bath solutions by regularly testing bath chemistries
for key contaminants and concentrations. The system then adjusts the process bath by making
small chemical additions, as needed, to keep contaminant build-up to a minimum and the process
bath operating as directed. The resulting process bath operates more efficiently, resulting in
prolonged bath life, less chemical waste, reduced chemical cost, and reduced drag-out.
Controlling rinse water flow is an inexpensive process function to automate. Techniques
for controlling rinse water flow were discussed previously. The reduction in fresh water usage as
a result of automating these techniques will not only reduce water costs, but will also result in
reduced treatment chemical usage and less sludge.
A conveyorized system integrates many of the methods described above into a complete
automated MHC system. The system utilizes a series of process stages connected by a horizontal
conveyor to transport the PWB panels through the MHC process. Drag-out is greatly reduced
due, in part, to the separate process stages, and to the vertical alignment of the drilled holes that
trap less chemicals. Since drag-out is reduced, much less rinse water is required to cleanse the
panel surfaces, resulting in reduced water and treatment costs. A single water tank is sufficient
between process baths where multiple stages may be required in a non-conveyorized process,
thus dramatically reducing the number of process stages required, resulting in a much shorter
cycle time and reduced floor space requirements. The enclosed process stages limit evaporative
losses, reducing chemical costs, while also reducing the amount of chemical to which an
employee is exposed. Several MHC alternative chemistry processes have been designed to
operate effectively using this type of conveyorized system.
A conveyorized system should also take advantage of other pollution prevention
techniques, such as water flow controllers, bath maintenance techniques, and other methods
discussed throughout this module, to further reduce waste. By integrating all of these methods
together into a single MHC system, the process operates more efficiently, reducing water and
chemical consumption, resulting in less process waste and employee exposure.
Segregate Wastewater Streams to Reduce Sludge Generation. Another type of
process improvement to prevent pollution relates to segregating the wastewater streams
generated by MHC and other PWB manufacturers process steps. The segregation of wastewater
streams is a simple and cost-effective pollution prevention technique for the MHC process. In a
typical PWB facility, wastewater streams from different process steps are often combined and
then treated by an on-site wastewater treatment process to comply with local discharge limits.
Some waste streams from the MHC process, however, may contain chelating agents.
These chelators, which permit metal ions to remain dissolved in solution at high pH levels, must
first be broken down chemically before the waste stream can be treated and the heavy metal ions
removed. Treatment of waste containing chelators requires extra treatment steps or more active
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chemicals to break down the chelating agents and precipitate out the heavy metal ions from the
remaining water effluent. Because the chelator-bearing streams are combined with other non-
chelated streams before being treated, a larger volume of waste must be treated for chelators than
is necessary, which also results in a larger volume of sludge.
To minimize the amount of treatment chemical used and sludge produced, the chelated
waste streams should be segregated from the other non-chelated wastes and collected in a storage
tank. When enough waste has been collected, the chelated wastes should be batch treated to
breakdown the chelator and remove the heavy metals. The non-chelated waste streams can then
be treated by the on-site wastewater treatment facility without additional consideration. By
segregating and batch treating the chelated heavy metal wastes from other non-hazardous waste
streams, the volume of waste undergoing additional treatment is minimized and treatment
chemical usage and sludge generation reduced.
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^ 6.2 RECYCLE, RECOVERY, AND CONTROL TECHNOLOGIES ASSESSMENT
6.2 RECYCLE, RECOVERY, AND CONTROL TECHNOLOGIES ASSESSMENT
While pollution prevention is the preferred method of waste management, the waste
management hierarchy recognizes that pollution prevention is not always feasible. Companies
often supplement their pollution prevention efforts with additional waste management techniques
to further reduce emissions. These techniques, presented in order of preference, include
recycling, treatment, and disposal. This section presents waste management techniques typically
used by the PWB industry in the MHC process to minimize waste, recycle or recover valuable
process resources, and to control emissions to water and air.
6.2.1 Recycle and Resource Recovery Opportunities
PWB manufacturers have begun to reevaluate the merits of recycle and recovery
technologies because of more stringent effluent pretreatment regulations. Recycling is the in-
process recovery of process material effluent, either on-site or off-site, which would otherwise
become a solid waste, air emission, or a wastewater stream. Metals recycling and recovery
processes have become more economical to operate due to the increased cost of managing sludge
containing heavy metals under stricter regulatory requirements. Technologies that recycle water
from waste streams concentrate the final effluent making subsequent treatment more efficient,
thus reducing the volume of waste generated along with overall water and sewer costs. As a
result, these technologies are being used more frequently by industry to recycle or recover
valuable process resources while also minimizing the volume of waste that is sent to disposal.
This trend was supported by the respondents of the Pollution Prevention Survey (EPA, 1995c),
76 percent of whom reported using some type of recycle or resource recovery technology.
Recycle and resource recovery technologies include those that recover materials from
waste streams before disposal or recycle waste streams for reuse in another process.
Opportunities for both types of technologies exist within the MHC process. Rinse water can be
recycled and reused in further rinsing operations while copper can be recovered from waste
streams before disposal and sold to a metals reclaimer. These recycle and recovery technologies
may be either in-line (dedicated and built into the process flow of a specific process line) or at-
line (employed at the line as desired as well as other places in the plant) technologies depending
on what is required (Brooman, 1996). Each individual waste stream that cannot be prevented
should be evaluated to determine its potential for effective recycle or resource recovery.
The decision on whether to purchase a recycle or resource recovery process should be
based on several factors. Economic factors such as process operating costs and effluent disposal
costs for the current system must be compared with those estimated for the new technology. The
initial capital investment of the new technology along with any potential cost savings and the
length of the payback period must also be considered. Other factors such as the characteristics of
the waste stream(s) considered for treatment, the ability of the process to accept reused or
recycled materials, and the effects of the recycle or recovery technology on the overall waste
treatment process should also be considered.
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The entire PWB manufacturing process must be considered when assessing the economic
feasibility of a recycle or resource recovery process. An individual recovery process can recover
copper from a single stream originating from the MHC process, or it may recover the metal from
streams that originate from other processes as well. Only by considering the new technology's
impact on the entire process, can an accurate and informed decision be made. While this section
focuses on technologies that could be used to recycle or recover resources from the waste streams
that are generated from the MHC process, many of these technologies are applicable to other
PWB process lines. Workplace practices that can lead to the recycle or reuse of resources (e.g.,
manually recovering copper from panel racks, water recycle using cascade water rinse systems)
are discussed in Section 6.1.
Reverse Osmosis
Reverse osmosis is a recovery process used by the PWB industry to regenerate rinse
waters and to reclaim process bath drag-out for return to the process (EPA, 1990). It relies on a
semi-permeable membrane to separate the water from metal impurities allowing bath solutions to
be reused. It can be used as a recycling or recovery technology to reclaim or regenerate a
specific solution, or it can be part of an overall waste treatment process to concentrate metals and
impurities before final treatment.
The reverse osmosis process uses a semi-permeable membrane which permits only
certain components to pass through it and a driving force to separate these components at a
useful rate. The membrane is usually made of a polymer compound (e.g., nylon) with hole sizes
ranging from 0.0004 to 0.06 microns in diameter. High pressure pumping of the waste stream, at
pressures typically ranging from 300 to 1,500 pounds per square inch (psi) force the solution
through the membrane (Capsule Environmental Engineering, Inc., 1993). The membrane allows
the water to pass while inhibiting the metal ions, collecting them on the membrane surface. The
concentrated metal ions are allowed to flow out of the system where they are reused as bath
make-up solution or are sent to treatment. The relatively pure water can be recycled as rinse
water or directly sewered.
The reverse osmosis process has some limitations. The types of waste streams suitable
for processing are limited to the ability of the plastic membranes to withstand the destructive
nature of the given waste stream. The membranes are sensitive to solutions with extreme pH
values, either low or high, which can degrade the polymer membranes. Pure organic streams are
likewise not treatable. Waste streams with suspended solids should be filtered prior to separation
to keep the solids from fouling the membrane, thus reducing the efficiency of the process.
Process membranes may also have a limited life due to the long-term pressure of the solution on
the membrane (Coombs, 1993). Data regarding the usage of reverse osmosis technology by
industry was not collected by the Pollution Prevention Survey.
Ion Exchange
Ion exchange is a process used by the PWB industry mainly to recover metal ions, such
as copper or palladium, from rinse waters and other solutions. This process uses an exchange
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resin to remove the metal from solution and concentrate it on the surface of the resin. It is
particularly suited to treating dilute solutions, because it removes the metal species from the
solution instead of removing the solution from the metal. As a result, the relative economics of
the process improve as the concentration of the feed solution decreases. Aside from recovering
copper, ion exchange can also be used for treating wastewater, deionizing feed water, and
recovering chemical solutions.
Ion exchange relies on special resins, either cationic or anionic, to remove the desired
chemical species from solution. Cation exchange resins are used to remove positively charged
ions such as copper. When a feed stream containing copper is passed through a bed of cation
exchange resin, the resin removes the copper ions from the stream, replacing them with hydrogen
ions from the resin. For example, a feed stream containing copper sulfate (CuSO4) is passed
through the ion exchange resin where the copper ions are removed and replaced by hydrogen
ions to form sulfuric acid (H2SO4). The remaining water effluent is either further processed
using an anion exchange resin and then recirculated into the rinse water system, or pH
neutralized and then directly sewered. Ion exchange continues until the exchange resin becomes
saturated with metal ions and must be regenerated.
Special chelating resins have been designed to capture specific metal ions that are in the
presence of chelating agents, such as metal ions in electroless plating baths. These resins are
effective in breaking down the chemical complexes formed by chelators that keep metal ions
dissolved in solution, allowing them to be captured by the resin. They ignore hard water ions,
such as calcium and magnesium that would otherwise be captured, creating a more pure
concentrate. Chelating resins require that the feed stream be pH adjusted to reduce acidity and
filtered to remove suspended solids that will foul the exchange bed (Coombs, 1993).
Regeneration of the cation or chelating exchange resin is accomplished using a
moderately concentrated (e.g., 10 percent) solution of a strong acid, such as sulfuric acid.
Regeneration reverses the ion exchange process by stripping the metal ions from the exchange
resin and replacing them with hydrogen ions from the acid. The concentration of metal ions in
the remaining regenerant depends on the concentration of the acid used, but typically ranges from
10 to 40 g/L or more (Coombs, 1993).
Ionic exchange can be combined with electrowinning (electrolytic recovery) to recover
metal from solutions that would not be cost-effective to recover using either technology alone. It
can be used to concentrate a dilute solution of metal ions for electrolytic recovery that would
otherwise be uneconomical to recover. For example, a dilute copper chloride solution can be
treated by an ion exchange unit which is regenerated using sulfuric acid, producing a
concentrated copper sulfate solution. The electrowinning unit can then be used to recover the
copper from the solution while regenerating the acid, which could then be used for the next
regeneration cycle.
A benefit of ion exchange is the ability to control the type of metallic salt that will be
formed by selecting the type of acid used to regenerate the resin. In the previous example, the
copper chloride was converted to copper sulfate while being concentrated by the ion exchange
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system. This is particularly useful when electrowinning is used, since it cannot process solutions
containing the chlorine ion without generating toxic chlorine gas.
Twenty-six percent of the respondents to the Pollution Prevention Survey reported using
an ion exchange process as a water recycle/chemical recovery technology. The average capital
cost of a unit, which is related to its capacity, reported by the respondents was $47,500 with a
low of $5,000 and a high of $100,000.
Electrolytic Recovery
Electrolytic recovery, also known as electrowinning, is a common metal recovery
technology employed by the PWB industry. Operated either in continuous or batch mode,
electrowinning can be applied to various process fluids including spent microetch, drag-out rinse
water, and ion exchange regenerant. An advantage of electrowinning, which uses an electrolytic
cell to recover dissolved copper ions from solution, is its ability to recover only the metal from
solution without recovering the other impurities that are present. The recovered copper can then
be sold as scrap or reused in the process.
Process waste solutions containing chlorine ions in any form should not be processed
using electrolytic recovery methods since the electrolysis of these solutions could generate
chlorine gas. Solutions containing copper chloride salts should first be converted using ion
exchange methods to a non-chloride copper salt (e.g., copper sulfate) solutions before undergoing
electrowinning to recover the copper content (Coombs, 1993).
Electrowinning is most efficient with concentrated solutions. Dilute solutions
with less than 100 mg/L of copper become uneconomical to treat due to the high power
consumption relative to the amount of copper recovered (Coombs, 1993). Waste streams that are
to be treated should be segregated to prevent dilution and to prevent the introduction of other
metal impurities. Already diluted solutions can be concentrated first using ion exchange or
evaporation techniques to improve the efficiency and cost-effectiveness of metal recovery.
The electrolytic cell is comprised of a set of electrodes, both cathodes and anodes, placed
in the copper laden solution. An electric current, or voltage, is applied across the electrodes and
through the solution. The positively charged metal ions are drawn to the negatively charged
cathode where they deposit onto the surface. The solution is kept thoroughly mixed using air
agitation, or other proprietary techniques, which allow the process to use higher current densities
(the amount of current per surface area of cathode) that speed deposition time and improve
efficiency. As copper recovery continues, the concentration of copper ions in solution becomes
depleted, requiring the current density to be reduced to maintain efficiency. When the
concentration of copper becomes too low for its removal to be economically feasible, the process
is discontinued and the remaining solution is sent to final treatment.
The layers of recovered copper can be sold as scrap to a metals reclaimer. Copper
removal efficiencies of 90 to 95 percent have been achieved using electrolytic methods (EPA,
1990). The remaining effluent will still contain small amounts of copper and will be acidic in
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^ 6.2 RECYCLE, RECOVERY, AND CONTROL TECHNOLOGIES ASSESSMENT
nature (i.e., low pH). Adjusting the pH may not be sufficient for the effluent to meet the
standards of some POTW authorities; therefore, further treatment may be required.
Eighteen percent of the Pollution Prevention Survey respondents reported using
electrowinning as a resource recovery technology with nearly all (89 percent) being satisfied.
The median cost of a unit reported by the respondents was $15,000; however, electrowinning
capital costs are dependant on the capacity of the unit.
6.2.2 Control Technologies
If the release of a hazardous material cannot be prevented or recycled, it may be possible
to treat or reduce the impact of the release using a control technology. Control technologies are
engineering methods that minimize the toxicity and volume of released pollutants. Most of these
methods involve altering either the physical or chemical characteristics of a waste stream to
isolate, destroy, or alter the concentration of target chemicals. While this section focuses on
technologies that are used to control on-site releases from the MHC process, many of these
technologies are also applicable to other PWB process lines.
Control technologies are typically used to treat on-site releases to both water and air from
the operation of the MHC process. Wastewater containing concentrations of heavy metal ions,
along with chelators and complexing agents, are of particular concern. Water effluent standards
require the removal of most heavy metals and toxic organics from the plant effluent before it can
be disposed to the sewer. On-site releases to air of concern include formaldehyde vapors, as well
as acid and solvent fumes. The desire to eliminate both formaldehyde and chelating agents has
led to the development of alternative MHC processes. This section identifies the control
technologies used by PWB manufacturers to treat or control wastewater and air emissions
released by the operation of the MHC process.
Wastewater Treatment
Chemical Precipitation. In the PWB industry, the majority of facilities surveyed (61
percent) reported using a conventional chemical precipitation system to accomplish the removal
of heavy metal ions from wastewater. Chemical precipitation is a process for treating wastewater
that depends on the water solubility of the various compounds formed during treatment. Heavy
metal cations that are present in the wastewater are reacted with certain treatment chemicals to
form metal hydroxides, sulfides, or carbonates that all have relatively low water solubilities. The
resulting heavy metal compounds are then precipitated from the solution as an insoluble sludge
that is subsequently recycled to reclaim the metals content or sent to disposal. The chemical
precipitation process can be operated as a batch process, but is typically operated in a continuous
process to treat wastewater.
In the chemical precipitation treatment of wastewater from PWB manufacturing, the
removal of heavy metals may be carried out by a unit sequence of rapid mix precipitation,
flocculation, and clarification. The process begins with the dispersion of treatment chemicals
into the wastewater input stream under rapid mixing conditions. The initial mixing unit is
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6.2 RECYCLE, RECOVERY, AND CONTROL TECHNOLOGIES ASSESSMENT
designed to create a high intensity of turbulence in the reactor vessel, promoting encounters
between the metal ions and the treatment chemical species, which then react to form metal
compounds that are insoluble in water. The type of chemical compounds formed depends on the
treatment chemical employed; this is discussed in detail later in this section. These insoluble
compounds form a fine precipitate at low pH levels that remains suspended in the wastewater.
The wastewater then enters the flocculation tank. The purpose of the flocculation step is
to transform smaller precipitation particles into large particles that are heavy enough to be
removed from the water by gravity settling in the clarification step. This particle growth is
accomplished in a flocculation tank using slow mixing to promote the interparticle collisions of
precipitate particles suspended in the wastewater. The degree of flocculation is enhanced
through the use of flocculating chemicals such as cationic or anionic polymers. These chemicals
promote interparticle adhesion by adding charged particles to the wastewater that attach
themselves to the precipitate, thereby increasing the growth rate of the precipitate particles.
Clarification is the final stage of the wastewater treatment process. The wastewater
effluent from the flocculation stage is fed into a clarification tank where the water is allowed to
collect undisturbed. The precipitate then settles out of the water by gravity, forming a blanket of
sludge at the bottom of the clarification tank. A portion of the sludge, typically 10 to 25 percent,
is often recirculated to the head of the flocculation step to reduce chemical requirements, as well
as to enhance the rate of precipitation (Frailey, 1996). The sludge particles provide additional
precipitation nuclei that increase the probability of particle collisions, resulting in a more dense
sludge deposit. When a dense layer of sludge has been formed, the sludge is removed from the
tank and is either dewatered or sent for recycle or disposal. The precipitate-free water is then
either recycled or sewered.
Other process steps are sometimes employed in the case of unusually strict effluent
guidelines. Filtration, reverse osmosis, ion exchange, or additional precipitation steps are
sometimes employed to further reduce the concentration of chemical contaminants present in the
wastewater effluent.
The heavy metal sludge generated by the wastewater treatment process is often
concentrated, or dewatered, before being sent to recycle or disposal. Sludge can be dewatered in
several methods including sludge thickening, press filtration, and sludge drying. Through the
removal of water, sludge volume can be minimized, thus reducing the cost of disposal.
Treatment of Non-Chelated Wastewater. The absence of complexing chemicals (e.g,.
ammonia) or chelating agents (e.g., EDTA) in the wastewater stream simplifies the removal of
heavy metal ions by precipitation. Heavy metal removal from such waste streams is
accomplished through simple pH adjustment using hydroxide precipitation. Caustic soda
(NaOH) is typically used while other treatment chemicals include calcium hydroxide and
magnesium hydroxide. The heavy metal ions react with the caustic soda to form insoluble metal
hydroxide compounds that precipitate out of solution at a high pH level. After the precipitate is
removed by gravity settling, the effluent is pH adjusted to a pH of seven to nine and then
sewered. The treatment can be performed in a chemical precipitation process similar to the one
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6.2 RECYCLE, RECOVERY, AND CONTROL TECHNOLOGIES ASSESSMENT
described above, resulting in a sludge contaminated with metals that is then sent to recycling or
disposal.
Treatment of Wastewater Containing Chelated Metals. The presence of complexing
chemicals or chelators require a more vigorous effort to achieve a sufficient level of heavy metal
removal. Chelators are chemical compounds that inhibit precipitation by forming chemical
complexes with the metals, allowing them to remain in solution beyond their normal solubility
limits. These chemicals are found in spent MHC plating baths, in cleaners, and in the water
effluent from the rinse tanks following these baths. Treatment chemicals enhance the removal of
chelated metals from water by breaking the chelant-to-metal bond, destroying the soluble
complex. The freed metal ions then react to form insoluble metal compounds, such as metal
hydroxides, that precipitate out of solution. Several different chemicals are currently being used
to effectively treat chelator-contaminated wastewater resulting from the manufacture of PWBs.
Some common chemicals used in the treatment of wastewater produced by the MHC process are
briefly described in Table 6.6. For a more information regarding individual treatment chemicals
and their applicability to treating specific wastes, consult the supplier of the treatment chemical.
Table 6.6 Treatment Chemicals Used to Remove Heavy Metals From
Chelated Wastewater
Chemical
Description
Ferrous Sulfate
Inexpensive treatment that requires iron concentrations in excess of 8:1
to form an insoluble metal hydroxide precipitate (Coombs, 1993).
Ferrous sulfate is first used as a reducing agent to breakdown the
complexed copper structures under acidic conditions before forming the
metal hydroxide during subsequent pH neutralization. Drawbacks
include the large volumes of sludge generated and the presence of iron
which reduces the value of sludge to a reclaimer.
DTC
(Dimethyl-dithiocarbamate)
Moderately expensive chemical that acts as a complexing agent,
exerting a stronger reaction to the metal ion than the chelating agent,
effectively forming an insoluble heavy metal complex. The sludge
produced is light in density and difficult to gravity separate (Guess,
1992;Frailey, 1996).
Sodium Sulfide
Forms heavy metal sulfides with extremely low solubilities that
precipitate even in the presence of chelators. Produces large volume of
sludge that is slimy and difficult to dewater (Guess, 1992).
Polyelectrolyte
Polymers that remove heavy metals effectively without contributing to
the volume of sludge. Primary drawback is the high chemical cost
(Frailey, 1996).
Sodium Borohydride
Strong reducing agent reduces heavy metal ions which then precipitate
out of solution forming a compact, low volume sludge. Drawbacks
include its high chemical cost and the evolution of potentially explosive
hydrogen gas (Guess, 1992; Frailey, 1996).
Ferrous Dithionite
Reduces heavy metal ions under acidic conditions to form metallic
particles that are recovered by gravity separation. Excess iron is
regenerated instead of being precipitated producing a low volume sludge
(Guess, 1992).
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6.2 RECYCLE, RECOVERY, AND CONTROL TECHNOLOGIES ASSESSMENT
Effects of MHC Alternatives On Wastewater Treatment. The strong desire to remove
both formaldehyde and complexing chemicals, such as chelators, from the MHC process has led
the drive away from traditional electroless copper and toward the development of alternative
MHC processes. These processes eliminate the use of chelating agents that inhibit the
precipitation of heavy metal ions in wastewater. Also eliminated is the need for expensive
treatment chemicals, which are designed to breakdown chelators and which can add to the
quantity of sludge produced. The resulting treatment of the non-chelated waste stream produces
less sludge at a lower chemical treatment cost than it would if chelators were present. A detailed
description of the treatment for both chelated and non-chelated wastes is presented elsewhere in
this chapter.
While MHC alternative processes may reduce or eliminate the presence of chelators in
the wastewater, they do not create any additional treatment concerns that would require any
physical changes in the treatment process. The treatment of wastewater generated from the
operation of a MHC alternative can be accomplished using the traditional chemical precipitation
stages of rapid mix precipitation, flocculation, and clarification.
Alternative Treatment Processes. Although chemical precipitation is the most common
process for treating wastewater by PWB manufacturers, other treatment processes exist as well.
Survey respondents reported the use of both ion exchange (33 percent) and/or electrowinning (12
percent) to successfully treat wastewater generated from the manufacture of PWBs. These
processes operate separately, or in combination, to efficiently remove heavy metal ions from
chelated or non-chelated waste streams, typically yielding a highly concentrated sludge for
disposal. These processes were discussed in Section 6.2.1.
Batch Treatment of Process Baths. Most spent process baths can be mixed with other
wastewater and treated by the on-site wastewater treatment process using chemical precipitation.
Chemical suppliers, however, recommend that some process baths be treated separately from the
usual waste treatment process. The separate treatment of these baths is usually recommended
due to the presence of strong chelating agents, high heavy metal concentrations, or other
chemicals, such as additives or brighteners, that require additional treatment measures before
they can be disposed of properly. Spent bath solution requiring special treatment measures can
be processed immediately, but is typically collected and stored until enough has accumulated to
warrant treatment. Batch treatment of the accumulated waste is then performed in a single tank
or drum, following the specific treatment procedures provided by the chemical supplier for that
bath.
Despite the supplier's recommendations, PWB facilities sometimes treat individual
process baths using their typical wastewater treatment process. Spent bath solutions can be
mixed slowly, in small quantities, with other wastewater before being treated, thus diluting the
concentration of the chemical species requiring treatment. However, the introduction of
concentrated wastes to the wastewater could result in increased treatment chemical consumption
and more sludge produced than if batch treated separately. Also the introduction of a chemical
species not typically found in the wastewater may adversely affect the treatment process or
require more vigorous treatment chemicals or processes. Factors affecting the success of such
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6.2 RECYCLE, RECOVERY, AND CONTROL TECHNOLOGIES ASSESSMENT
treatment include the type of treatment chemicals used, the contaminant concentrations in the
wastewater, and the overall robustness of the treatment process.
Air Pollution Control Technologies
Air pollution control technologies are often used by the PWB industry to cleanse air
exhaust streams of harmful fumes and vapors. Exactly half (50 percent) of the PWB facilities
surveyed have installed air scrubbers to control air emissions from various manufacturing
processes, and almost a quarter of the facilities (23 percent) scrub air releases from the MHC
process. The first step of any air control process is the effective containment of fugitive air
emissions at their source of release. This is accomplished using fume hoods over the process
areas from which the air release of concern is emanating. These hoods may be designed to
continuously collect air emissions for treatment by one of the methods described below.
Gas Absorption. One method for removing pollutants from an exhaust stream is by gas
absorption in a technique sometimes referred to as air scrubbing. Gas absorption is defined as
the transfer of material from a gas to a contacting liquid, or solvent. The pollutant is chemically
absorbed and dispersed into the solvent leaving the air free of the pollutant. The selection of an
appropriate solvent should be based upon the liquids' solubility for the solute, and the cost of the
liquid. Water is used for the absorption of water soluble gases while alkaline solutions are
typically used for the absorption of acid gases. Air scrubbers are used by the PWB industry to
treat wet process air emissions, such as formaldehyde and acid fumes, and emissions from other
processes outside the MHC process.
Gas absorption is typically carried out in a packed gas absorption tower, or scrubber. The
gas stream enters the bottom of the tower, and passes upward through a wetted bed of packing
material before exiting the top. The absorbing liquid enters the top of the tower and flows
downward through the packing before exiting at the bottom. Absorption of the air pollutants
occurs during the period of contact between the gas and liquid. The gas is either physically or
chemically absorbed and dispersed into the liquid. The liquid waste stream is then sent to water
treatment before being discharged to the sewer. Although the most common method for gas
absorption is the packed tower, other methods exist such as plate towers, sparged towers, spray
chambers, or venturi scrubbers (Cooper, 1990).
Gas Adsorption. The removal of low concentration organic gases and vapors from an
exhaust stream can be achieved by the process of gas adsorption. Adsorption is the process in
which gas molecules are retained on the interface surfaces of a solid adsorbent by either physical
or chemical forces. Activated carbon is the most common adsorbent but zeolites such as alumina
and silica are also used. Adsorption is used primarily to remove volatile organic compounds
from air, but is also used in other applications such as odor control and drying process gas
streams (Cooper, 1990). In the MHC process it can be used to recover volatile organic
compounds, such as formaldehyde.
Gas adsorption occurs when the vapor-laden air is collected and then passed through a
bed of activated carbon, or another adsorbent material. The gas molecules are adsorbed onto the
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6.2 RECYCLE, RECOVERY, AND CONTROL TECHNOLOGIES ASSESSMENT
surface of the carbon, while the clean vapor-free air is exhausted from the system. The adsorbent
material eventually becomes saturated with organic material and must be replaced or regenerated.
Adsorbent canisters, which are replaced on a regular basis, are typically used to treat small gas
flow streams. Larger flows of organic pollutants require packed beds of adsorbent material,
which must be regenerated when the adsorbent becomes saturated (Cooper, 1990).
Regeneration of the adsorbent is typically accomplished by a steam stripping process.
The adsorbent is contacted with low pressure steam which desorbs the adsorbed gas molecules
from the surface of the packed bed. Following condensation of the steam, the organic material is
recovered from the water by either decanting or distillation (Campbell, 1990).
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REFERENCES
REFERENCES
Bayes, Martin. 1996. Shipley Company. Personal communication to Jack Geibig, UT
Center for Clean Products and Clean Technologies. January.
Brooman, Eric. 1996. Concurrent Technologies Corporation. Personal communication to Lori
Kincaid, UT Center for Clean Products and Clean Technologies. August 5.
Campbell, M. and W. Glenn. 1982. "Profit from Pollution Prevention. Pollution Probe
Foundation.
Capsule Environmental Engineering, Inc. 1993. "Metal Finishing Pollution Prevention Guide."
Prepared for Minnesota Association of Metal Finishers in conjunction with The
Minnesota Technical Assistance Program. Prepared by Capsule Environmental
Engineering, Inc., 1970 Oakcrest Avenue, St. Paul, MN 55113. July.
Coombs, Jr., Clyde. 1993 Printed Circuits Handbook. 4th ed. McGraw-Hill.
Cooper, David C. and F.C. Alley. 1990. Air Pollution Control: A Design Approach.
Waveland Press, Prospect Heights, IL.
Edwards, Ted. 1996. Honeywell. Personal communication to Lori Kincaid, UT Center for
Clean Products and Clean Technologies. July 10.
Fehrer, Fritz. 1996. Silicon Valley Toxics Coalition. Personal communication to Lori
Kincaid, UT Center for Clean Products and Clean Technologies. July 22.
Frailey, Dean. 1996. Morton International. Personal communication to Jack Geibig, UT Center
for Clean Products and Clean Technologies. May 7.
Guess, Robert. 1992. Romar Technologies. United States Parent* 5,122,279. July 16.
Kling, David J. 1995. Director, Pollution Prevention Division, Office of Pollution Prevention
and Toxics. Memo to Regional OPPT, Toxics Branch Chiefs. February 17.
U.S. Environmental Protection Agency (EPA). 1990. Guides to Pollution Prevention: The
Printed Circuit Board Manufacturing Industry. EPA Office of Resource and
Development, Cincinnati, OH. EPA/625/7-90/007. June.
U.S. Environmental Protection Agency (EPA). 1995a. "Printed Wiring Board Case Study 1:
Pollution Prevention Work Practices." Pollution Prevention Information Clearinghouse
(PPIC). Washington, DC. EPA 744-F-95-004. July.
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REFERENCES
U.S. Environmental Protection Agency (EPA). 1995b. "Printed Wiring Board Case Study 2:
On-Site Etchant Regeneration." Pollution Prevention Information Clearinghouse (PPIC).
Washington, DC. EPA 744-F-95-005. July.
U.S. Environmental Protection Agency (EPA). 1995c. Printed Wiring Board Pollution
Prevention and Control: Analysis of Survey Results. EPA Office of Pollution
Prevention and Toxics. Washington, DC. EPA 744-R-95-006. September.
U.S. Environmental Protection Agency (EPA). 1995d. Federal Environmental Regulations
Affecting the Electronics Industry. EPA Office of Pollution Prevention and Toxics.
Washington, DC. EPA744-B-95-001. September.
U.S. Environmental Protection Agency. (EPA). 1996a. "Printed Wiring Board Project:
Opportunities for Acid Recovery and Management." Pollution Prevention Information
Clearinghouse (PPIC). Washington, DC. EPA 744-F-95-009. September.
U.S. Environmental Protection Agency. (EPA). 1996b. "Printed Wiring Board Project: Plasma
Desmear: A Case Study." Pollution Prevention Information Clearinghouse (PPIC).
Washington, DC. EPA 744-F-96-003. September.
U.S. Environmental Protection Agency. (EPA). 1996c. "Printed Wiring Board Project: A
Continuous-Flow System for Reusing Microetchant." Pollution Prevention Information
Clearinghouse (PPIC). Washington, DC. EPA 744-F-96-024. December.
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Chapter 7
Choosing Among MHC Technologies
This chapter of the Cleaner Technologies Substitutes Assessment (CTSA) organizes data
collected or developed throughout the assessment of the baseline non-conveyorized electroless
copper process and alternatives in a manner that facilitates decision-making. First, risk,
competitiveness, and conservation data are summarized in Section 7.1. This information is used
in Section 7.2 to assess the net benefits and costs to society of implementing an alternative as
compared to the baseline. Section 7.3 provides summary profiles for the baseline and
alternatives.
Information is presented for eight technologies for performing the making holes
conductive (MHC) function. These technologies are electroless copper, carbon, conductive ink,
conductive polymer, graphite, non-formaldehyde electroless copper, organic-palladium, and tin-
palladium. All of these technologies are wet chemistry processes, except the conductive ink
technology, which is a screen printing technology.1 The wet chemistry processes can be operated
using vertical, immersion-type, non-conveyorized equipment or horizontal, conveyorized
equipment.2 Table 7.1 presents the processes (alternatives and equipment configurations)
evaluated in the CTSA.
Table 7.1 MHC Processes Evaluated in the CTSA8
MHC Technology
Electroless Copper (BASELINE)
Carbon
Conductive Polymer
Graphite
Non-Formaldehyde Electroless Copper
Organic-Palladium
Tin-Palladium
Equipment Configuration
Jfon-Conveyorisced
/
/
/
/
Conveyomed
^
/
S
/
/
/
8 The human health and aquatic toxicity hazards and chemical safety hazards of the conductive ink technology were
also evaluated, but risk was not characterized.
1 Only limited analyses were performed on the conductive ink technology for two reasons: 1) the process
is not applicable to multi-layer boards, which were the focus of the CTSA; and 2) sufficient data were not available
to characterize the risk, cost, and energy and natural resources consumption of all of the relevant process steps (e.g.,
preparation of the screen for printing, the screen printing process itself, and screen reclamation).
2 Conveyorized MHC equipment is a relatively new innovation in the industry, and is usually more
efficient than non-conveyorized equipment. Many of the newer technologies are only being used with conveyorized
equipment, while most facilities in the U.S. still use a non-conveyorized electroless copper process to perform the
MHC function.
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7.1 RISK. COMPETITIVENESS. AND CONSERVATION DATA SUMMARY
The results of the CTSA suggest that the alternatives not only have environmental and
economic benefits compared to the non-conveyorized electroless copper process, but also
perform the MHC function as well as the baseline. While there appears to be enough
information to show that a switch away from traditional electroless copper processes has reduced
risk benefits, there is not enough information to compare the alternatives to this process among
themselves for all their environmental and health consequences. This is due to a lack of
proprietary chemical data from suppliers3 and because toxicity values are not available for some
chemicals. In addition, it is important to note that there are additional factors beyond those
assessed in this CTSA which individual businesses may consider when choosing among
alternatives. None of these sections make value judgements or recommend specific alternatives.
The actual decision of whether or not to implement an alternative is made outside of the CTSA
process.
7.1 RISK, COMPETITIVENESS, AND CONSERVATION DATA SUMMARY
Earlier sections of the CTSA evaluated the risk, performance, cost, and resource
requirements of the baseline MHC technology as well as the alternatives. This section
summarizes the findings associated with the analysis of MHC technologies. Relevant data
include the following:
• Risk information: occupational health risks, public health risks, ecological hazards, and
process safety concerns.
• Competitiveness information: technology performance, cost and regulatory status, and
international information.
• Conservation information: energy and natural resource use.
Sections 7.1.1 through 7.1.3 present risk, competitiveness, and conservation summaries,
respectively.
7.1.1 Risk Summary
This risk characterization uses a health-hazard based framework and a model facility
approach to compare the health risks of one MHC process technology to the risks associated with
switching to an alternative technology. As much as possible, reasonable and consistent
assumptions are used across alternatives. Data to characterize the model facility and exposure
patterns for each process alternative were aggregated from a number of sources, including printed
wiring board (PWB) shops in the U.S. and abroad, supplier data, and input from PWB
manufacturers at project meetings. Thus, the model facility is not entirely representative of any
3 Electrochemical, LeaRonal, and Solution Technology Systems have provided information on
proprietary chemical ingredients to the project. W.R. Grace was preparing to provide proprietary information on
chemical ingredients in the conductive ink technology when it was determined that this information was no longer
necessary because risk from the conductive ink technology could not be characterized. The other suppliers
participating in the project (Atotech, Enthone-OMI, MacDermid, and Shipley) have declined to provide proprietary
information.
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7.1 RISK, COMPETITIVENESS, AND CONSERVATION DATA SUMMARY
one facility, and actual risk could vary substantially, depending on site-specific operating
conditions and other factors.
When using the results of the risk characterization to compare health effects among
alternatives, it is important to remember that it is a screening level rather than a comprehensive
risk characterization, both because of the predefined scope of the assessment and because of
exposure and hazard data limitations. It should also be noted that this approach does not result in
any absolute estimates or measurements of risk, and even for comparative purposes there are
several important uncertainties associated with this assessment (see Section 3.4).
The exposure assessment for the risk characterization used, whenever possible, a
combination of central tendency and high-end assumptions (i.e., 90 percent of actual values are
expected to be less) to yield an overall high-end exposure estimate. Some values used in the
exposure calculations, however, are better characterized as "what-if,"4 especially pertaining to
bath concentrations, use of gloves, and process area ventilation rates for a model facility.
Because some part of the exposure assessment for both inhalation and dermal exposures qualifies
as a "what-if descriptor, the entire assessment should be considered "what-if."
As with any risk characterization, there are a number of uncertainties involved in the
measurement and selection of hazard data, and in the data, models, and scenarios used in the
exposure assessment. Uncertainties arise both from factors common to all risk characterizations
(e.g., extrapolation of hazard data from animals to humans, extrapolation from the high doses
used in animal studies to lower doses to which humans may be exposed, missing toxicity data,
including data on the cumulative or synergistic effects of chemical exposure), and other factors
that relate to the scope of the risk characterization (e.g., the MHC characterization is a screening
level characterization rather than a comprehensive risk assessment). Key uncertainties in this
characterization include the following:
• The risk characterization is based on publicly-available bath chemistry data, which do not
include the identity or concentrations of chemicals considered trade secrets by chemical
suppliers.5
• The risk estimates for occupational dermal exposure are based on limited dermal toxicity
data, using oral toxicity data with oral to dermal extrapolation when dermal toxicity data
were unavailable. Coupled with the high uncertainty in estimating dermal absorption
rates, this could result in either over- or under-estimates of exposure and risk.
• The risk characterization is based on modeled estimates of average, steady-state chemical
concentrations in air, rather than actual monitoring data of average and peak air
concentrations.
4 A "what-if description represents an exposure estimate based on postulated questions, making
assumptions based on limited data where the distribution is unknown.
5 Electrochemicals, LeaRonal, and Solution Technology Systems have provided information on
proprietary chemical ingredients to the project for evaluation in the risk characterization. Atotech, Enthone-OMI,
MacDermid, and Shipley have not. Risk results for proprietary ingredients, but not chemical identities or
concentrations, will be included in the final CTSA.
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7.1 RISK, COMPETITIVENESS, AND CONSERVATION DATA SUMMARY
• The risk characterization does not account for any side reactions occurring in the baths,
which could either underestimate exposures to toxic reaction products or overestimate
exposures to toxic chemicals that react in the bath to form more benign chemicals.
• Due to resource constraints, the risk characterization does not address all types of
exposures that could occur from MHC processes or the PWB industry, including short-
term or long-term exposures from sudden releases due to fires, spills, or other periodic
releases.
The Risk Characterization section of the CTSA (Section 3.4) discusses the uncertainties in this
characterization in detail.
Occupational Health Risks
Health risks to workers were estimated for inhalation exposure to vapors and aerosols
from MHC baths and for dermal exposure to MHC bath chemicals. Inhalation exposure
estimates are based on the assumptions that emissions to indoor air from conveyorized lines are
negligible, that the air in the process room is completely mixed and chemical concentrations are
constant over tune, and that no vapor control devices (e.g., bath covers) are used in non-
conveyorized lines. Dermal exposure estimates are based on the assumption that workers do not
wear gloves6 and that all non-conveyorized lines are operated by manual hoist. Dermal exposure
to line operators on non-conveyorized lines could occur from routine line operation and
maintenance (e.g., bath replacement, filter replacement, etc.). Dermal exposure to line operators
on conveyorized lines was assumed to occur from bath maintenance activities alone.
Risk results indicate that alternatives to the non-conveyorized electroless copper process
pose lower occupational risks. However, there are occupational inhalation risk concerns for
some chemicals hi the non-formaldehyde electroless copper and tin-palladium non-conveyorized
processes. In addition, there are occupational risk concerns for dermal contact with some
chemicals in the conveyorized electroless copper process and non-formaldehyde electroless
copper and tin-palladium processes for either conveyorized or non-conveyorized equipment.
Finally, occupational health risks could not be quantified for one or more of the chemicals used
in each of the MHC technologies. This is due to the fact that proprietary chemicals in the baths
were not identified by suppliers7 and to missing toxicity or chemical property data for some
chemicals known to be present in the baths.
Table 7.2 presents chemicals of concern for potential occupational risk from inhalation.
Table 7.3 presents chemicals of concern for potential occupational risk from dermal contact.
6 Many PWB manufacturers report that their employees routinely wear gloves in the process area.
However, risk from dermal contact was estimated assuming workers do not wear gloves to account for those
workers who do not wear proper personal protective equipment.
7 Some of the chemical suppliers have provided information on proprietary chemical ingredients to the
project for evaluation in the risk characterization. Risk results for proprietary ingredients, but not chemical
identifies or concentrations, will be included in the final CTSA.
DRAFT
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7.1 RISK, COMPETITIVENESS, AND CONSERVATION DATA SUMMARY
Table 7.2 MHC Chemicals of Concern for Potential Occupational Inhalation Risk
Chemical*
Copper Chloride
Ethanolamine
2-Ethoxyethanol
Ethylene Glycol
Formaldehyde
Methanol
Sulfuric Acidc
Non-Conveyorized Process11
Eleetroless Copper
/
/
/
/
/
/
/
Non-Formaldekyde
Electroless Copper
«/
Tin-Palladium
/
/
concern that are present in all of the product lines evaluated are indicated in bold.
b Occupational inhalation exposure from conveyorized lines was assumed to be negligible.
c Sulfuric acid was listed on the MSDSs for all of the electroless copper lines evaluated and four of the five tin-
palladium lines evaluated.
Table 7.3 MHC Chemicals of Concern for Potential Occupational Dermal Risk
Chemical11
Copper Chloride
Fluoroboric Acid
Formaldehyde
Palladium11
Palladium Chlorideb
Sodium Chlorite
Stannous Chloride'
Electroless Copper
Line Operator
NC
/
/
^
/
/
/
C
/
/
/
/
,/
/
Lab
Tech
(NC or C)
/
/
/
Non-Formaldehyde
Electroless Copper
Line Operator
(NC)
^
/
Tin-Palladium
Line Operator
NC
/
/
/
/
S
C
s
s
s
s
s
Lab
Tech
(NCorC)
/
/
/
/
\_\J\_ l.t'^/lliH-'lV&lWkJ VV tkli IIJ-VAV* 1.11U.11 \jil\s viiWiAiiVi^i uv.|^^**.**i ^"*53*5 •»»»»-—- — — — — ~ff i fj
concern that are present in all of the product lines evaluated are indicated in bold.
b Palladium or palladium chloride was listed on the MSDSs for three of the five tin-palladium lines evaluated. The
MSDSs for the two other lines did not list a source of palladium. Palladium and palladium chloride are not listed on
the MSDSs for all of the electroless copper lines evaluated.
0 Stannous chloride was listed on the MSDSs for four of the five tin-palladium lines evaluated. The MSDSs for the
remaining line did not list a source of tin. Stannous chloride is not listed on the MSDSs for all of the electroless
copper lines evaluated.
NC: Non-Conveyorized.
C: Conveyorized.
The non-conveyorized' electroless copper process is the only process for which an
occupational cancer risk has been estimated (for formaldehyde). Formaldehyde has been
classified by EPA as Group B1, a Probable Human Carcinogen. The upper bound excess
individual cancer risk estimate for line operators in the non-conveyorized electroless copper
process from formaldehyde inhalation may be as high as one in 1,000, but may be 50 times less,
DRAFT
7-5
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7.1 RISK, COMPETITIVENESS, AND CONSERVATION DATA SUMMARY
or one in 50,000.8 Risks to other workers were assumed to be proportional to the amount of time
spent in the process area, which ranged from three percent to 61 percent of the risk for a line
operator.
Other identified chemicals in the MHC processes are suspected carcinogens.
Dimethylformamide and carbon black have been determined by the International Agency for
Research on Cancer (IARC) to possibly be carcinogenic to humans (IARC Group 2B). Like
formaldehyde, the evidence for carcinogenic effects is based on animal data. However, unlike
formaldehyde, slope factors are not available for either chemical. There are potential cancer risks
to workers from both chemicals, but they cannot be quantified. Dimethylformamide is used in
the electroless copper process. Workplace exposures have been estimated but cancer potency
and cancer risk are unknown. Carbon black is used in the carbon and conductive ink processes.
Occupational exposure due to air emissions from the carbon baths in the carbon process is
expected to be negligible because this process is typically conveyorized and enclosed. There
may be some airborne carbon black, however, from the drying oven steps. Exposures from
conductive ink were not characterized.
Public Health Risks
Public health risk was estimated for inhalation exposure only for the general populace
living near a facility. Environmental releases and risk from exposure to contaminated surface
water were not quantified due to a lack of data; chemical constituents and concentrations in
wastewater could not be adequately characterized. Public health risk estimates are based on the
assumption that emissions from both conveyorized and non-conveyorized process configurations
are steady-state and vented to the outside. Risk was not characterized for short-term exposures to
high levels of hazardous chemicals when there is a spill, fire, or other periodic release.
The risk indicators for ambient exposures to humans, although limited to airborne
releases, indicate low concern from all MHC technologies for nearby residents. The upper bound
excess individual cancer risk for nearby residents from the non-conveyorized electroless copper
process was estimated to be from approaching zero to 1 x 10'7 (one in ten million), and from
approaching zero to 3 x 10'7 (one in three million) for the conveyorized electroless copper
process. Formaldehyde has been classified by EPA as Group Bl, a Probable Human Carcinogen.
The risk characterization for ambient exposure to MHC chemicals also indicates low concern
from the estimated air concentrations for chronic non-cancer effects.
Ecological Hazards
The CTSA methodology typically evaluates ecological risks in terms of risks to aquatic
organisms in streams that receive treated or untreated effluent from manufacturing processes.
* To provide further information on the possible variation of formaldehyde exposure and risk, an
additional exposure estimate was provided in the Risk Characterization (Section 3.4) using average and median
values (rather than high-end) as would be done for a central tendency exposure estimate. This results in
approximately a 35-fold reduction in occupational formaldehyde exposure and risk from the estimates presented
here.
DRAFT
7-6
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7.1 RISK, COMPETITIVENESS, AND CONSERVATION DATA SUMMARY
Stream concentrations of MHC chemicals were not available, however, and could not be
estimated because of insufficient chemical characterization of constituents and their
concentrations in facility wastewater.9 To qualitatively assess risk to aquatic organisms, MHC
chemicals were ranked based on aquatic toxicity values according to established EPA criteria for
aquatic toxicity of high, moderate, or low concern (see Section 3.3.3).
Table 7.4 presents the number of MHC chemicals evaluated for each alternative, the
number of chemicals in each alternative with aquatic toxicity of high, moderate, or low concern,
the chemicals with the lowest concern concentration (CC) by alternative, and the bath
concentrations of the chemicals with the lowest CC. The aquatic toxicity concern level could
not be evaluated for some chemicals that have no measured aquatic toxicity data or established
structure-activity relationships to estimate their aquatic toxicity. Aquatic toxicity rankings are
based only on chemical toxicity to aquatic organisms, and are not an expression of risk.
Table 7.4 Aquatic Hazard Data
Alternative
Electroless Copper
Carbon
Conductive Ink
Conductive Polymer
Graphite
Non-Formaldehyde
Electroless Copper
Organic-Palladium
Tin-Palladium
No. of
Chemicals
Evaluated3
42C
8C
llc
6
8
10
6
21C
No. of Chemicals
by Aquatic Hazard
Concern Level8
High
9
2
2
0
3
3
1
7
Medium
16
2
1
1
2
3
3
5
Low
16
3
7
5
3
4
2
8
. Chemical with
Lowest CC
copper sulfate
(0.00002 mg/1)
copper sulfate
(0.00002 mg/1)
silver
(0.000036 mg/1)
peroxymonosulfuric acid
(0.030 mg/1)
copper sulfate
(0.00002 mg/1)
copper sulfate
(0.00002 mg/1)
sodium hypophosphite
(0.006 mg/1)
copper sulfate
(0.00002 mg/1)
Bath
Concentration
of Chemical
With Lowest CCb
4.8 to 12 g/1
5.0 g/1
NA
26.85 g/1
2.7 g/1
22 g/1
75 g/ld
0.2 to 13 g/1
For technologies with more than one chemical supplier (e.g., electroless copper, graphite, and tin-palladium), all
chemicals may not be present in any one product line.
b Bath concentrations are shown as a range for technologies supplied by more than one chemical supplier and are
based on publicly-available bath chemistry data.
c No aquatic hazard data available for one chemical.
d Chemical is in microetch bath. Concentration in bath may be overestimated, because MSDS reports both
chemicals in bath (sodium persulfate and sodium bisulfate) are present in concentrations < 75 percent (< 75 g/1).
NA: Not Applicable.
9 There are well-documented copper pollution problems associated with discharges to surface waters and
many of the MHC alternatives contain copper compounds. However, there were no data available to estimate the
relative concentration of copper in different MHC line effluents. In addition, no data were available for surface
water concentrations of other chemicals, especially chemicals in alternatives to electroless copper processes. Thus,
risk to aquatic organisms were not characterized.
DRAFT
7-7
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7.1 RISK, COMPETITIVENESS, AND CONSERVATION DATA SUMMARY
A CC is the concentration of a chemical in the aquatic environment which, if exceeded,
may result in significant risk to aquatic organisms. CCs were determined by dividing acute or
chronic toxicity values by an assessment factor (ranging from one to 1,000) that incorporates the
uncertainty associated with toxicity data. CCs are discussed in more detail in Section 3.3.3.
The number of chemicals with a high aquatic hazard concern level include nine in the
electroless copper process, two in carbon, two in conductive ink, none in conductive polymer,
three in graphite, three in non-formaldehyde electroless copper, one hi organic-palladium, and
seven hi tin-palladium. However, for technologies supplied by more than one chemical supplier
(e.g., electroless copper, graphite, and tin-palladium), all chemicals of high aquatic toxicity
concern may not be present in any one product line. The lowest CC is for copper sulfate, which
is found in five of the MHC technology categories: carbon, electroless copper, graphite, non-
formaldehyde electroless copper, and tin-palladium. Bath concentrations of copper sulfate vary,
ranging from a high of 22 g/1 for the non-formaldehyde electroless copper technology to a
low of 0.2 g/1 in one of the tin-palladium processes (and, based on MSDS data, not present in the
conductive ink, organic-palladium, or conductive polymer processes).
Process Safety
Workers can be exposed to two types of hazards affecting occupational safety and health:
chemical hazards and process hazards. Workers can be at risk through exposure to chemicals and
because they work hi proximity to automated equipment. In order to evaluate the chemical
safety hazards of the various MHC technologies, MSDSs for chemical products used with each
of the MHC technologies were reviewed. Table 7.5 summarizes the hazardous properties of
MHC chemical products.
Table 7.5 Hazardous Properties of MHC Chemical Products
MHC Technology
Electroless Copper
Carbon
Conductive Ink
Conductive Polymer
Graphite
Non-Formaldehyde
Electroless Copper
Organic-Palladium
Tin-Palladium
No. of
MSDSs
Reviewed1"
68
11
5
8
12
19
8
38
Number of Chemical Products with Hazardous Properties*
Flammable
7
7
0
1
0
3
0
2
Combustible
1
0
0
0
0
0
0
1
Explosive
1
0
5
0
0
0
0
1
Fire
Hazard
1
0
0
0
1
0
0
1
Corrosive
29
5
0
5
4
4
0
12
Oxidizer
6
2
0
0
1
3
0
0
* For technologies with more than one chemical supplier (e.g., electroless copper, graphite, and tin-palladium), all
chemicals with hazardous properties may not be present in any one product line.
b Reflects the combined number of MSDSs for all product lines evaluated in a technology category.
DRAFT
7-8
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7.1 RISK, COMPETITIVENESS, AND CONSERVATION DATA SUMMARY
Table 7.5 Hazardous Properties of MHC Chemical Products (cont.)
MHC Technology
Electroless Copper
Carbon
Conductive Ink
Conductive Polymer
Graphite
Non-Formaldehyde
Electroless Copper
Organic-Palladium
Tin-Palladium
No. of
MSDSs
Reviewed1"
68
11
5
8
12
19
8
38
Number of Chemical Products with Hazardous Properties8
Reactive
16
2
0
0
0
4
0
3
Unstable
1
0
0
0
1
0
1
0
Sensitizer
0
0
0
0
0
0
0
2
Acute Health
Hazard
14
11
0
0
8
9
0
9
Chronic Health
Hazard
10
9
0
0
4
5
0
5
Eye
Damage
34
12
2
6
4
7
4
22
a For technologies with more than one chemical supplier (e.g., electroless copper, graphite, and tin-palladium), all
chemicals with hazardous properties may not be present in any one product line.
b Reflects the combined number of MSDSs for all product lines evaluated in a technology category.
Other potential chemical hazards can occur because of hazardous decomposition of
chemical products, or chemical product incompatibilities with other chemicals or materials.
With few exceptions, most chemical products used hi MHC technologies can decompose under
specific conditions to form potentially hazardous chemicals. In addition, all of the MHC
processes have chemical products with incompatibilities that can pose a threat to worker safety if
the proper care is not taken to prevent such occurrences.
Work-related injuries from equipment, improper use of equipment, bypassing equipment
safety features, failure to use personal protective equipment, and physical stresses that may
appear gradually as a result of repetitive motion are all potential process safety hazards to
workers. Regardless of the technology used, of critical importance is an effective and ongoing
safety training program. Characteristics of an effective worker health and safety program
include:
• An employee training program.
• Employee use of personal protective equipment.
• Proper chemical storage and handling.
• Safe equipment operating procedures.
Without appropriate training, the number of worker accidents and injuries is likely to
increase, regardless of the technology used. A key management responsibility is to ensure that
training is not compromised by pressure to meet production demands or by cost-cutting efforts.
7.1.2 Competitiveness Summary
The competitiveness summary provides information on basic issues traditionally
important to the competitiveness of a business: the performance characteristics of its products
DRAFT
7-9
-------
7.1 RISK, COMPETITIVENESS, AND CONSERVATION DATA SUMMARY
relative to industry standards; the direct and indirect costs of manufacturing its products; its need
or ability to comply with environmental regulations; and factors influencing world-wide markets
for its products or technologies that may affect its competitiveness. The final evaluation of a
technology involves considering these traditional competitiveness issues along with issues that
business leaders now know are equally important competitiveness issues: the health and
environmental impacts of alternative products, processes, and technologies.
Performance
The performance of the MHC technologies was tested using production run tests. In
order to complete this evaluation, PWB panels, designed to meet industry "middle-of-the-road"
technology, were manufactured at one facility, run through individual MHC lines at 26 facilities,
then electroplated at one facility. The panels were electrically prescreened, followed by
electrical stress testing and mechanical testing, in order to distinguish variability in the
performance of the MHC interconnect. The test methods used to evaluate performance were
intended to indicate characteristics of a technology's performance, not to define parameters of
performance or to substitute for thorough on-site testing; the study was intended to be a
"snapshot" of the technologies. The Performance Demonstration was conducted with extensive
input and participation from PWB manufacturers, their suppliers, and PWB testing laboratories.
The technologies tested included electroless copper (the baseline), carbon, conductive
ink10, conductive polymer, graphite, non-formaldehyde electroless copper, and palladium.11 The
test vehicle was a 24 x 18" 0.062" 8-layer panel. (See Section 4.1 for a detailed description of
the test vehicle.) Each test site received three panels for processing through the MHC line.
Test sites were submitted by suppliers of the technologies, and included production
facilities, testing facilities (beta sites), and supplier testing facilities. Because the test sites were
not chosen randomly, the sample may not be representative of all PWB manufacturing facilities
(although there is no specific reason to believe that they are not representative). In addition, the
number of test sites for each technology ranged from one to ten. Due to the smaller number of
test sites for some technologies, results for these technologies could more easily be due to chance
than the results from technologies with more test sites. Statistical relevance could not be
determined.
Product performance for this study was divided into two functions: plated-through hole
(PTH) cycles to failure and the integrity of the bond between the internal lands (post) and PTH
(referred to as "post separation"). The PTH cycles to failure observed in this study is a function
of both electrolytic plating and the MHC process. The results indicate that each MHC
10 The conductive ink test panels were processed through the MHC process and sent for testing. The
supplier of the technology felt that because the test vehicle used was incompatible with the capabilities of the
conductive ink technology, the test results were not indicative of the capabilities of the technology. Therefore, the
results of the conductive ink technology are not reported.
" The Performance Demonstration included both organic and tin-palladium processes in the overall
palladium category.
DRAFT
7-10
-------
7.1 RISK, COMPETITIVENESS, AND CONSERVATION DATA SUMMARY
technology has the capability to achieve comparable (or superior) levels of performance to
electroless copper. Post separation results indicated percentages of post separation that were
unexpected by many members of the industry. It was apparent that all MHC technologies,
including electroless copper, are susceptible to this type of failure.
Cost
Comparative costs were estimated using a hybrid cost model which combined traditional
costs with simulation modeling and activity-based costs. The cost model was designed to
determine the total cost of processing a specific amount of PWB through a fully operational
MHC line, in this case, 350,000 surface square feet (ssf). Total costs were divided by the
throughput (350,000 ssf) to determine a unit cost in $/ssf. The cost model did not estimate start-
up costs for a facility switching to an MHC alternative or the cost of other process changes that
may be required to implement an MHC alternative.
The cost components considered include capital costs (primary equipment, installation,
and facility costs), materials costs (limited to chemical costs), utility costs (water, electricity, and
natural gas costs), wastewater cost (limited to wastewater discharge cost), production costs
(production labor and chemical transport costs), and maintenance costs (tank cleanup, bath setup,
sampling and analysis, and filter replacement costs). Other cost components may contribute
significantly to overall costs, but were not quantified because they could not be reliably
estimated. These include wastewater treatment cost, sludge recycling and disposal cost, other
solid waste disposal costs, and quality costs. However, Performance Demonstration results
indicate that each MHC technology has the capability to achieve comparable levels of
performance to electroless copper. Thus, quality costs are not expected to differ among the
alternatives.
Table 7.6 presents results of the cost analysis, which indicate all of the alternatives are
more economical than the non-conveyorized electroless copper process. In general,
conveyorized processes cost less than non-conveyorized processes. Costs ranged from $0.51/ssf
for the baseline process to $0.09/ssf for the conveyorized conductive polymer process. Seven
process alternatives cost less than or equal to $0.20/ssf (conveyorized carbon at $0.18/ssf,
conveyorized conductive polymer at $0.09/ssf, conveyorized electroless copper at $0.15/ssf,
conveyorized organic-palladium at $0.17/ssf, non-conveyorized organic-palladium at $0.15/ssf,
and conveyorized and non-conveyorized tin-palladium at $0.12/ssf and $0.14/ssf, respectively).
Three processes cost more than $0.20/ssf; all of these processes are non-conveyorized (non-
conveyorized electroless copper at $0.51/ssf, non-conveyorized non-formaldehyde electroless
copper at $0.40/ssf, and conveyorized graphite at $0.22/ssf).
DRAFT
7-11
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7.1 RISK, COMPETITIVENESS, AND CONSERVATION DATA SUMMARY
Table 7.6 CostofMHC Technologies
Cost Category
Capital Cost
Material Cost
Utility Cost
Wastewater Cost
Production
Cost
Maintenance
Cost
Cost Components
Primary Equipment
Installation
Facility
Chemicals
Water
Electricity
Natural Gas
Wastewater Discharge
Transportation of Material
Labor for Line Operation
Tank Cleanup
Bath Setup
Sampling and Testing
Filter Replacement
Total Cost
Unit Cost (S/ssf)
Electroless Copper,
non-conveyorized
$64,000
$11,200
$8,690
$22,500
$6,540
$2,780
$0
$13,800
$737
$36,100
$5,430
$1,220
$4,260
$2,800
$180,000
$0.51
Carbon,
conveyorized
$7,470
$299
$2,690
$32,900
$725
$836
$418
$1,750
$446
$10,200
$3,280
$740
$405
$116
$62,300
$0.18
Conductive Polymer,
conveyorized
$5,560
$0
$2,250
$10,400
$410
$460
$0
$987
$673
$5,830
$4,960
$1,120
$436
$376
$33,500
$0.09
Cost Category
Capital Cost
Material Cost
Utility Cost
Wastewater Cost
Production
Cost
Maintenance
Cost
Cost Components
Primary Equipment
Installation
Facility
Chemicals
Water
Electricity
Natural Gas
Wastewater Discharge
Transportation of Material
Labor for Line Operation
Tank Cleanup
Bath Setup
Sampling and Testing
Filter Replacement
Total Cost
Unit Cost (S/ssf)
Electroless
Copper,
conveyorized
$6,190
$212
$2,800
$22,600
$642
$669
$0
$1,480
$883
$7,230
$6,500
$1,460
$942
$612
$52,200
$0.15
Graphite,
conveyorized
$3,580
$131
$1,090
$59,800
$251
$462
$145
$637
$319
$6,700
$2,350
$529
$316
$901
$77,200
$0.22
Non-Formaldehyde
Electroless Copper,
non-Conveyorized
$29,300
$5,120
$3,350
$69,600
$2,100
$1,310
$0
$4,580
$682
$16,200
$5,030
$1,130
$691
$214
$139,300
$0.40
DRAFT
7-12
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7.1 RISK, COMPETITIVENESS, AND CONSERVATION DATA SUMMARY
Table 7.6 Cost of MHC Technologies (cont.)
Cost Category
Capital Cost
Material Cost
Utility Cost
Wastewater Cost
Production
Cost
Maintenance
Cost
Total Cost
Cost Components
Primary Equipment
Installation
?acility
Chemicals
Water
Electricity
Natural Gas
Wastewater Discharge
Transportation of Material
Labor for Line Operation
Tank Cleanup
Bath Setup
Sampling and Testing
Filter Replacement
Unit Cost ($/ssf)
Organic-Palladium,
conveyorized
$5,780
$356
$2,220
$28,900
$635
$720
$0
$1,540
$1,260
$6,530
$9,250
$2,080
$411
$271
$60,000
$0.17
Organic-Palladium,
non-conveyorized
$4,160
$256
$1,100
$27,000
$325
$0
$1,690
$1,050
$7,190
$7,710
$1,740
$288
$385
$53,700
$0.15
Cost Category
Capital Cost
Material Cost
Utility Cost
Wastewater Cost
Production
Cost
Maintenance
Cost
Total Cost
Cost Components
Primary Equipment
nstallation
Facility
Chemicals
Water
Electricity
Natural Gas
Wastewater Discharge
Transportation of Material
Labor for Line Operation
Tank Cleanup
Bath Setup
Sampling and Testing
Filter Replacement
Unit Cost ($/ssf)
Tin-Palladium,
conveyorized
$1,280
$205
$1,490
$25,500
$317
$468
$0
$774
$537
$5,230
$3,950
$891
$493
$332
$41,500
$0.12
Tin-Palladium,
non-conveyorized
$4,760
$381
$1,910
$22,300
$1,010
$635
$0
$2,380
$455
$10,700
$3,350
$755
$916
$616
$50,200
$0.14
7-13
DRAFT
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7.1 RISK, COMPETITIVENESS, AND CONSERVATION DATA SUMMARY
Chemical cost was the single largest component cost for nine of the ten processes.
Equipment cost was the largest cost for the non-conveyorized electroless copper process. Three
separate sensitivity analyses of the results indicated that chemical cost, production labor cost, and
equipment cost have the greatest effect on the overall cost results.
Regulatory Status
Discharges of MHC chemicals may be restricted by federal, state or local air, water or
solid waste regulations, and releases may be reportable under the federal Toxic Release
Inventory program. Federal environmental regulations were reviewed to determine the federal
regulatory status of MHC chemicals.12 Table 7.7 lists the number of chemicals used in an MHC
technology with federal environmental regulations restricting or requiring reporting of their
discharges. Different chemical suppliers of a technology do not always use the same chemicals
in their particular product lines. Thus, all of these chemicals may not be present in any one
product line.
International Information
The total world market for PWBs is approximately $21 billion (EPA, 1995). The U.S.
and Japan are the leading suppliers of PWBs, but Hong Kong, Singapore, Taiwan, and Korea are
increasing their market share. Information on the use of MHC technologies worldwide was
collected to assess whether global trends affect the competitiveness of an alternative.
The alternatives to the traditional electroless copper MHC process are in use in many
countries. Most of the suppliers of these alternatives have manufacturing facilities located in
countries to which they sell. Several suppliers indicated the market shares of the alternatives are
increasing internationally quicker than they are increasing in the U.S. The cost-effectiveness of
an alternative has been the main driver causing PWB manufacturers abroad to switch from an
electroless copper process to one of the newer alternatives. In addition to the increased capacity
and decreased labor requirements of some of the MHC alternatives over the electroless copper
process, environmental concerns also affected the process choice. For instance, the rate at which
an alternative consumes water and the presence or absence of strictly regulated chemicals are two
factors which have a substantial effect on the cost-effectiveness of MHC alternatives abroad.
While environmental regulations do not seem to be the primary forces leading toward the
adoption of the newer alternatives, it appears that the companies that supply these alternatives are
taking environmental regulations and concerns into consideration when designing alternatives.
12 In some cases, state or local requirements may be more restrictive than federal requirements. However,
due to resource limitations, only federal regulations were reviewed.
DRAFT
7-14
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7.1 RISK, COMPETITIVENESS. AND CONSERVATION DATA SUMMARY
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DRAFT
-------
7.1 RISK, COMPETITIVENESS, AND CONSERVATION DATA SUMMARY
7.1.3 Resource Conservation Summary
Resources typically consumed by the operation of the MHC process include water used
for rinsing panels, process chemicals used on the process line, energy used to heat process baths
and power equipment, and wastewater treatment chemicals. A quantitative analysis of the energy
and water consumption rates of the MHC process alternatives was performed to determine if
implementing an alternative to the baseline process would reduce consumption of these resources
during the manufacturing process. A quantitative analysis of both process chemical and
treatment chemical consumption could not be performed due to the variability of factors that
affect the consumption of these resources. Section 5.1 discusses the role the MHC process has in
the consumption of these resources and the factors affecting the consumption rates.
The relative water and energy consumption rates of the MHC process alternatives were
determined as follows:
• The daily water consumption rate and hourly energy consumption rate of each alternative
were determined based on data collected from the Workplace Practices Survey.
• The operating time required to produce 350,000 ssf of PWB was determined using
computer simulations models of each of the alternatives.
• The water and energy consumption rates per ssf of PWB were calculated based on the
consumption rates and operating times.
Table 7.8 presents the results of these analyses.
Table 7.8 Energy and Water Consumption Rates of MHC Alternatives
Process Type
Electroless Copper, non-conveyorized (BASELINE)
Electroless Copper, conveyorized
Carbon, conveyorized
Conductive Polymer, conveyorized
Graphite, conveyorized
Non-Formaldehyde Electroless Copper, non-conveyorized
Organic-Palladium, non-conveyorized
Organic-Palladium, conveyorized
Tin-Palladium, non-conveyorized
Tin-Palladium, conveyorized
Water
Consumption
(gal/ssf)
11.7
1.15
1.29
0.73
0.45
3.74
1.35
1.13
1.80
0.57
Energy
Consumption
(Btu/ssf)
573
138
514
94.7
213
270
66.9
148
131
96.4
The energy consumption rates ranged from 66.9 Btu/ssf for the non-conveyorized
organic-palladium process to 573 Btu/ssf for the non-conveyorized electroless copper process.
The results indicate that all of the MHC alternatives are more energy efficient than the baseline
process. They also indicate that for alternatives with both types of automation, the conveyorized
version of the process is typically more energy efficient, with the notable exception of the
organic-palladium process.
DRAFT
7-16
-------
7.1 RISK, COMPETITIVENESS, AND CONSERVATION DATA SUMMARY
An analysis of the impacts directly resulting from the consumption of energy by the
MHC process showed that the generation of the required energy has environmental impacts.
Pollutants released to air, water, and soil can result in damage to both human health and the
environment. The consumption of natural gas tends to result in releases to the air which
contribute to odor, smog, and global warming, while the generation of electricity can result in
pollutant releases to all media with a wide range of possible affects. Since all of the MHC
alternatives consume less .energy than the baseline, they all result in less pollutant releases to the
environment.
Water consumption rates ranged from 0.45 gal/ssf for the graphite process to 11.7 gal/ssf
for the non-conveyorized electroless copper process. In addition, results indicate that all of the
alternatives consume significantly less water than the baseline process. Conveyorized processes
were found to consume less water than non-conveyorized versions of the same process.
The rate of water consumption is directly related to the rate of wastewater generation.
Most PWB facilities discharge process rinse water to an on-site wastewater treatment facility for
pretreatment prior to discharge to a publicly-owned treatment works (POTW). A pollution
prevention analysis identified a number of pollution prevention techniques that can be used to
reduce rinse water consumption. These include use of more efficient rinse configurations, use of
flow control technologies, and use of electronic sensors to monitor contaminant concentrations in
rinse water. Further discussion of these and other pollution prevention techniques can be found
in the Pollution Prevention section of this CTSA (Section 6.1) and in PWB Project Case Study 1
(EPA, 1995).
DRAFT
7-17
-------
7.2 SOCIAL BENEFITS/COSTS ASSESSMENT
7.2 SOCIAL BENEFITS/COSTS ASSESSMENT
7.2.1 Introduction to Social Benefits/Costs Assessment
Social benefits/costs analysis13 is a tool used by policy makers to systematically evaluate
the impacts to all of society resulting from individual decisions. The decision evaluated in this
analysis is the choice of an MHC technology. PWB manufacturers have a number of criteria
they may use to assess which MHC technology they will use. For example, a PWB manufacturer
might ask what impact their choice of an MHC alternative might have on operating costs,
compliance costs, liability costs, and insurance premiums. This business planning process is
unlike social benefit/cost analysis, however, because it approaches the comparison from the
standpoint of the individual manufacturer and not from the standpoint of society as a whole.
A social benefits/costs analysis seeks to compare the benefits and costs of a given action,
while considering both the private and external costs and benefits.14 Therefore, the analysis will
consider both the impact of the alternative MHC processes on the manufacturer itself (private
costs and benefits) and the impact the choice of an alternative has on external costs and benefits,
such as reductions in environmental damage and reductions in the risk of illness for the general
public. External costs are not borne by the manufacturer, rather they are the true costs to society.
Table 7.9 defines a number of terms used in benefit/cost assessment, including external costs and
external benefits.
13 The term "analysis" is used here to refer to a more quantitative analysis of social benefits and costs,
where a monetary value is placed on the benefits and costs to society of individual decisions. Examples of
quantitative benefits/costs analyses are the regulatory impact analyses done by EPA when developing federal
environmental regulations. The term "assessment" is used here to refer to a more qualitative examination of social
benefits and costs. The evaluation performed in the CTSA process is more correctly termed an assessment because
many of the social benefits and costs of MHC technologies are identified, but not monetized.
14 Private costs typically include any direct costs incurred by the decision maker and are generally
reflected in the manufacturer's balance sheet. In contrast, external costs are incurred by parties other than the
primary participants to the transaction. Economists distinguish between private and external costs because each will
affect the decision maker differently. Although external costs are real costs to some members of society, they are
not incurred by the decision maker and firms do not normally take them into account when making decisions. A
common example of these "externalities" is the electric utility whose emissions are reducing crop yields for the
farmer operating downwind. The external costs experienced by the farmer in the form of reduced crop yields are
not considered by the utility when making decisions regarding electricity production. The farmer's losses do not
appear on the utility's balance sheet.
DRAFT
7-18
-------
7.2 SOCIAL BENEFITS/COSTS ASSESSMENT
Table 7.9 Glossary of Benefits/Costs Analysis Terms
Term
Definition
Exposed
Population
The estimated number of people from the general public or a specific population group who are exposed
to a chemical through wide dispersion of a chemical in the environment (e.g., DDT). A specific
population group could be exposed to a chemical due to its physical proximity to a manufacturing facility
(e.g., residents who live near a facility using a chemical), use of the chemical or a product containing a
chemical, or through other means.
Exposed
Worker
Population
The estimated number of employees in an industry exposed to the chemical, process, and/or technology
under consideration. This number may be based on market share data as well as estimations of the number
of facilities and the number of employees in each facility associated with the chemical, process, and/or
technology under consideration.
Externality
A cost or benefit that involves a third party who is not a part of a market transaction; "a direct effect on
another's profit or welfare arising as an incidental by-product of some other person's or firm's legitimate
activity" (Mishan, 1976). The term "externality" is a general term which can refer to either external
benefits or external costs.
External
Benefits
A positive effect on a third party who is not a part of a market transaction. For example, if an educational
program results in behavioral changes which reduce the exposure of a population group to a disease, then
an external benefit is experienced by those members of the group who did not participate in the
educational program. For the example of nonsmokers exposed to second-hand smoke, an external benefit
can be said to result when smokers are removed from situations in which they expose nonsmokers to
tobacco smoke.
External
Costs
A negative effect on a third party who is not part of a market transaction. For example, if a steel mill
emits waste into a river which poisons the fish in a nearby fishery, the fishery experiences an external cost
as a consequence of the steel production. Another example of an external cost is the effect of second-hand
smoke on nonsmokers.
Human
Health
Benefits
Reduced health risks to workers in an industry or business as well as to the general public as a result of
switching to less toxic or less hazardous chemicals, processes, and/or technologies. An example would be
switching to a less volatile organic compound, lessening worker inhalation exposures as well as
decreasing the formation of photochemical smog in the ambient air.
Human
Health
Costs
The cost of adverse human health effects associated with production, consumption, and disposal of a
firm's product. An example is respiratory effects from stack emissions, which can be quantified by
analyzing the resulting costs of health care and the reduction in life expectancy, as well as the lost wages
as a result of being unable to work.
Illness
Costs
A financial term referring to the liability and health care insurance costs a company must pay to protect
itself against injury or disability to its workers or other affected individuals. These costs are known as
illness benefits to the affected individual.
Indirect
Medical
Costs
Indirect medical costs associated with a disease or medical condition resulting from exposure to a
chemical or product. Examples would be the decreased productivity of patients suffering a disability or
death and the value of pain and suffering borne by the afflicted individual and/or family and friends.
Private
(Internalized)
Costs
The direct costs incurred by industry or consumers in the marketplace. Examples include a firm's cost of
raw materials and labor, a firm's costs of complying with environmental regulations, or the cost to a
consumer of purchasing a product.
Social
Costs
The total cost of an activity that is imposed on society. Social costs are the sum of the private costs and
the external costs. Therefore, in the example of the steel mill, social costs of steel production are the sum
of all private costs (e.g., raw material and labor costs) and the sum of all external costs (e.g., the costs
associated with the poisoned fish).
Social
Benefits
The total benefit of an activity that society receives, i.e., the sum of the private benefits and the external
benefits. For example, if a new product yields pollution prevention opportunities (e.g., reduced waste in
production or consumption of the product), then the total benefit to society of the new product is the sum
of the private benefit (value of the product that is reflected in the marketplace) and the external benefit
(benefit society receives from reduced waste).
Willingness-
to-pay
Estimates used in benefits valuation are intended to encompass the full value of avoiding a health or
environmental effect. For human health effects, the components of willingness-to-pay include the value of
avoiding pain and suffering, impacts on the quality of life, costs of medical treatment, loss of income, and,
in the case of mortality, the value of life.
DRAFT
7-19
-------
7.2 SOCIAL BENEFITS/COSTS ASSESSMENT
Private benefits of the alternative MHC processes may include increased profits resulting
from improved worker productivity and company image, a reduction in energy use, or reduced
property and health insurance costs due to the use of less hazardous chemicals. External benefits
may include a reduction in pollutants emitted to the environment or reduced use of natural
resources. Costs of the alternative MHC processes may include private costs such as changes in
operating expenses and external costs such as an increase in human health risks and ecological
damage. Several of the benefit categories considered in this assessment share elements of both
private and external costs and benefits. For example, use of an alternative may result in natural
resource savings. Such a benefit may result in private benefits in the form of reduced water
usage and a resultant reduction in payments for water as well as external benefits in the form of
reduced consumption of shared resources.
7.2.2 Benefits/Costs Methodology and Data Availability
The methodology for conducting a social benefits/costs assessment can be broken down
into four general steps: 1) obtain information on the relative human and environmental risk,
performance, cost, process safety hazards, and energy and natural resource requirements of the
baseline and the alternatives; 2) construct matrices of the data collected; 3) when possible,
monetize the values presented within the matrices; and 4) compare the data generated for the
alternative and the baseline in order to produce an estimate of net social benefits. Section 7.1
presented the results of the first task by summarizing risk, competitiveness, and conservation
information for the baseline and alternative MHC technologies. Section 7.2.3 presents matrices
of private benefits and costs data, while Section 7.2.4 presents information relevant to external
benefits and costs. Section 7.2.5 presents the private and external benefits and costs together to
produce an estimate of net social benefits.
Ideally, the analysis would quantify the social benefits and costs of using the alternative
and baseline MHC technologies, allowing identification of the technology whose use results in
the largest net social benefit. This is particularly true for national estimates of net social benefits
or costs. However, because of resource and data limitations and because individual users of this
CTSA will need to apply results to their own particular situations, the analysis presents a
qualitative description of the risks and other external effects associated with each substitute
technology compared to the baseline. Benefits derived from a reduction in risk are described and
discussed, but not quantified. Nonetheless, the information presented can be very useful in the
decision-making process. A few examples are provided to qualitatively illustrate some of the
benefit considerations. Personnel in each individual facility will need to examine the
information presented, weigh each piece according to facility and community characteristics, and
develop an independent choice.
7.2.3 Private Benefits and Costs
While it is difficult to obtain an overall number to express the private benefits and costs
of alternative MHC processes, some data were quantifiable. For example, the cost analysis
estimated the average manufacturing costs of the MHC technologies, including the average
capital costs (primary equipment, installation, and facility cost), materials costs (limited to
chemical costs), utility costs (water, electricity, and natural gas costs), wastewater costs (limited
DRAFT
7-20
-------
7.2 SOCIAL BENEFITS/COSTS ASSESSMENT
to wastewater discharge cost), production cost (production labor and chemical transport costs),
and maintenance costs (tank cleanup, bath setup, sampling and analysis, and filter replacement
costs). Other cost components may contribute significantly to overall manufacturing costs, but
were not quantified because they could not be reliably estimated. These include wastewater
treatment cost, sludge recycling and disposal cost, other solid waste disposal costs, and quality
costs.
Differences in the manufacturing costs estimated in the cost analysis are summarized
below. However, in order to determine the overall private benefit/cost comparison, a qualitative
discussion of the data is also necessary. Following the discussion of manufacturing costs are
discussions of private costs associated with occupational and population health risks and other
private costs or benefits that could not be monetized but are important to the decision-making
process.
Manufacturing Costs
Table 7.10 presents the percent change in manufacturing costs for the MHC alternatives
as compared to the baseline. Only costs that were quantified in the cost analysis are presented.
All of the alternatives result in cost savings in the form of lower total costs; most of the
alternatives result in cost savings in almost every cost category. In addition, the Performance
Demonstration determined that each alternative has the capability to achieve comparable levels
of performance to electroless copper, thus quality costs are considered equal among the
alternatives. This is important to consider in a benefits/costs analysis since changes in
performance necessarily result in changed costs in the market. This is not the case in this
assessment since all alternatives yield comparable performance results.
Occupational Health Risks
Reduced risks to workers can be considered both a private and external benefit. Private
worker benefits include reductions in worker sick days and reductions in health insurance costs
to the PWB manufacturer. External worker benefits include reductions in medical costs to
workers in addition to reductions in pain and suffering associated with work-related illness.
External benefits from reduced risk to workers are discussed in more detail in Section 7.2.4.
DRAFT
7-21
-------
7.2 SOCIAL BENEFITS/COSTS ASSESSMENT
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7.2 SOCIAL BENEFITS/COSTS ASSESSMENT
Health risks to workers were estimated for inhalation exposure to vapors and aerosols
from MHC baths and for dermal exposure to MHC bath chemicals. Inhalation exposure
estimates are based on the assumptions that emissions to indoor air from conveyorized lines are
negligible, that the air in the process room is completely mixed and chemical concentrations are
constant over time, and that no vapor control devices (e.g., bath covers) are used in non-
conveyorized lines. Dermal exposure estimates are based on the assumption that workers do not
wear gloves and that all non-conveyorized lines are operated by manual hoist. Dermal exposure
to workers on non-conveyorized lines could occur from routine line operation and maintenance
(i.e., bath replacement, filter replacement, etc.). Dermal exposure to workers on conveyorized
lines was assumed to occur from bath maintenance alone. Worker dermal exposure to all MHC
technologies can be easily minimized by using proper protective equipment such as gloves
during MHC line operation and maintenance. In addition, many PWB manufacturers report that
their employees routinely wear gloves in the process area. Nonetheless, risk from dermal contact
was estimated assuming workers do not wear gloves to account for those workers who do not
wear proper personal protective equipment.
Because some parts of the exposure assessment for both inhalation and dermal exposures
qualify as "what-if" descriptors,15 the entire assessment should be considered "what-if." Table
7.11 summarizes the number of chemicals of concern for the exposure pathways evaluated and
lists the number of suspected carcinogens in each technology.
Based on the results of the risk characterization, it appears that alternatives to the non-
conveyorized electroless copper process have private benefits due to reduced occupational risks.
However, there are also occupational inhalation risk concerns for some chemicals in the non-
formaldehyde electroless copper and tin-palladium non-conveyorized processes. In addition,
there are occupational dermal exposure risk concerns for some chemicals in the conveyorized
electroless copper process and in the non-formaldehyde electroless copper and tin-palladium
processes with conveyorized or non-conveyorized equipment. Finally, occupational health risks
could not be quantified for one or more of the chemicals used in each of the MHC technologies.
This is due to the fact that proprietary chemicals in the baths are not included16 and to a lack of
toxicity or chemical property data for some chemicals known to be present in the baths.
15 A "what-if risk descriptor represents an exposure estimate based on postulated questions, making
assumptions based on limited data where the distribution is unknown.
16 Electrochemicals, LeaRonal, and Solution Technology Systems have provided information on
proprietary chemical ingredients to the project for evaluation in the risk characterization. Atotech, Enthone-OMI,
MacDermid, and Shipley have not. Risk results for proprietary chemicals, but not chemical identities or
concentrations, will be included in the final CTSA.
DRAFT
7-23
-------
7.2 SOCIAL BENEFITS/COSTS ASSESSMENT
Table 7.11 Summary of Occupational Hazards, Exposures, and Risks of Potential Concern
MHC Technology
Electroless Copper, non-conveyorized (BASELINE)
Electroless Copper, conveyorized
Carbon, conveyorized
Conductive Polymer, conveyorized
Graphite, conveyorized
Non-Formaldehyde Electroless Copper, non-conveyorized
Organic-Palladium, non-conveyorized
Organic-Palladium, conveyorized
Tin-Palladium, non-conveyorized
Tin-Palladium, conveyorized
No. of Chemicals of
Concern by Pathway"
Inhalation
7
0
0
0
0
1
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0
2-
0
Dermal
6
6
0
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2
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5
5
No, of
Suspected
Carcinogens
2b
2b
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0
0
0
0
0
* Number of chemicals of concern for an MHC line operator (the most exposed individual).
b Includes formaldehyde (EPA Group Bl, probable human carcinogen) and dimethylformamide (IARC Group 2B,
possible human carcinogen).
e Carbon black extracts have been determined by IARC to be possibly carcinogenic to humans (IARC Group 2B).
Carbon, but not carbon black extracts, is used hi the carbon and conductive ink technologies.
The non-conveyorized electroless copper process is the only process for which an
occupational cancer risk was estimated (for formaldehyde). Formaldehyde has been classified by
EPA as Group Bl, a Probable Human Carcinogen. Results indicate clear concern for
formaldehyde inhalation exposure; the upper bound excess individual cancer risk estimate for
line operators in the non-conveyorized electroless copper process from formaldehyde inhalation
may be as high as one in 1,000, but may be 50 times less, or one in 50,000.17 Risks to other
workers were assumed to be proportional to the amount of time spent in the process area, which
ranged from three percent to 61 percent of the risk for a line operator. Occupational risks from
dimethylformamide and carbon black exposures could not be quantified because cancer slope
factors have not been determined for these chemicals.
Public Health Risks
In addition to worker exposure, members of the general public may be exposed to MHC
chemicals due to their close physical proximity to a PWB plant or due to the wide dispersion of
chemicals. Reduced public health risks can also be considered both a private and external
benefit. Private benefits include reductions in potential liability costs; external benefits include
reductions in medical costs. External benefits from reduced public health risk are discussed in
more detail in Section 7.2.4.
" To provide further information on the possible variation of formaldehyde exposure and risk, an
additional exposure estimate was provided in the Risk Characterization (Section 3.4) using average and median
values (rather than high-end) as would be done for a central tendency exposure estimate. This results in
approximately a 35-fold reduction in occupational formaldehyde exposure and risk from the estimates presented
here.
DRAFT
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7.2 SOCIAL BENEFITSiXXJSTS ASSESSMENT
Public health risk was estimated for inhalation exposure only for the general populace
living near a facility. Environmental releases and risk from exposure to contaminated surface
water were not quantified due to a lack of data; chemical constituents and concentrations in
wastewater could not be adequately characterized. Public health risk estimates are based on the
assumption that emissions from both conveyorized and non-conveyorized process configurations
are steady-state and vented to the outside. Risk was not characterized for short-term exposures to
high levels of hazardous chemicals when there is a spill, fire, or other periodic release.
The risk indicators for ambient exposures to humans, although limited to airborne
releases, indicate low concern from all MHC technologies for nearby residents. The upper bound
excess individual cancer risk for nearby residents from the non-conveyorized electroless copper
process was estimated to be from approaching zero to 1 x 10"7 (one hi ten million), and from
approaching zero to 3 x 10"7 (one in three million) for the conveyorized electroless copper
process. The risk characterization for ambient exposure to other MHC chemicals also indicated
low concern from the estimated air concentrations for chronic non-cancer effects.
These results suggest little change in public health risks and, thus, private benefits or
costs if a facility switched from the baseline to an MHC alternative. However, it is important to
note that it was not within the scope of this comparison to assess all community health risks.
The risk characterization did not address all types of exposures that could occur from MHC
processes or the PWB industry, including short-term or long-term exposures from sudden
releases due to spills, fires, or other periodic releases.
Ecological Risks
MHC chemicals are potentially damaging to terrestrial and aquatic ecosystems, resulting
in both private costs borne by the manufacturers and external costs borne by society. Private
costs could include increased liability costs while external costs could include loss of ecosystem
diversity and reductions in the recreational value of streams and rivers. The CTSA evaluated the
ecological risks of the baseline and alternatives in terms of aquatic toxicity hazards. Aquatic risk
could not be estimated because chemical concentrations in MHC line effluents and streams were
not available and could not be estimated. It is not possible to reliably estimate concentrations
only from the MHC process since most PWB manufacturers combine MHC effluents with
effluents from other process lines.
Table 7.12 presents the number of chemicals in each technology with a high aquatic
hazard concern level. There are well documented copper pollution problems associated with
discharges to surface waters and many of the MHC alternatives contain copper compounds. The
lowest CC for an MHC chemical is for copper sulfate, which is found in five of the MHC
technology categories: electroless copper, carbon, graphite, non-formaldehyde electroless
copper, and tin-palladium. Bath concentrations of copper sulfate vary, ranging from a high of 22
g/1 for the non-formaldehyde electroless copper technology to a low of 0.2 g/1 in one of the tin-
palladium processes (and, based on MSDS data, not present in the conductive ink, conductive
polymer, or organic-palladium processes). Because the concentration of copper sulfate in
different MHC line effluents is not known, the benefits or costs of using one of these MHC
DRAFT
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7.2 SOCIAL BENEFITS/COSTS ASSESSMENT
alternatives cannot be assessed. For example, the non-formaldehyde electroless copper process
has a higher bath concentration of copper sulfate than the baseline; however, because the non-
formaldehyde electroless copper process does not contain the chelator EDTA, more copper may
be removed during wastewater treatment.
Table 7.12 Number of Chemicals with High Aquatic Hazard Concern Level
MHC Technology
Electroless Copper
Carbon
Conductive Ink
Conductive Polymer
Graphite
Non-Formaldehyde
Electroless Copper
Organic-Palladium
Tin-Palladium
No, of Chemicals
9
2
2
0
3
3
1
7
Plant-wide Benefits or Costs
The CTSA did not determine the PWB plant-wide benefits or costs that could occur from
implementing an alternative to the baseline MHC technology. However, a recent study of the
Davila International PWB plant in Mountain View, California, identified a number of changes to
the PWB manufacturing process that were only possible when an alternative to electroless copper
was installed. These changes reduced copper pollution and water use, resulting in cost savings.
A companion document to this publication, Implementing Cleaner Technologies in the Printed
Wiring Board Industry: Making Holes Conductive (EPA, 1997), describes some of the systems
benefits that can occur from implementing an MHC technology.
Improvements in the efficiency of the overall system not only provide private benefits,
but also social benefits.
In addition, the baseline MHC process is a production bottleneck in many shops, but the
alternative MHC technologies have substantially improved production rates. Thus, switching to
an alternative improves the competitiveness of a PWB manufacturer by enabling the same
number of boards to be produced faster or even enabling an increase in overall production
capacity. However, the increased productivity could have social costs if increased production
rates cause increased pollution rates in other process steps. Greater production rates in all the
processes should be coupled with pollution prevention measures.
Another cost could be incurred if increased production results in increased amounts of
scrap board. The Performance Demonstration determined that all of the alternatives have the
potential to perform as well as electroless copper if operated properly. However, vendors and
manufacturers who have implemented the alternatives stress the importance of taking a "whole-
process" view of new MHC technology installation. Process changes upstream or downstream
may be necessary to optimize alternative MHC processes (EPA, 1997). This is also important
DRAFT
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7.2 SOCIAL BENEFITS/COSTS ASSESSMENT
from a societal perspective because an increase in scrap boards can increase pollution generation
off-site. In particular, citizens groups are concerned about potential dioxin emissions from the
off-site process of secondary metal smelting which recycles scrap boards (Smith and Karras,
1997).
Other Private Benefits and Costs
Table 7.13 gives additional examples of private costs and benefits that could not be
quantified. These include wastewater treatment, solid waste disposal, compliance, liability,
insurance and worker illness costs, and improvements in company image that accrue from
implementing a substitute. Some of these were mentioned above, but are included in the table
due to their importance to overall benefits and costs.
7.2.4 External Benefits and Costs
External costs are those costs that are not taken into account in the manufacturer's pricing
and manufacturing decisions. These costs are commonly referred to as "externalities" and are
costs that are borne by society and not by the individuals who are part of a market transaction.
These costs can result from a number of different avenues in the manufacturing process. For
example, if a manufacturer uses a large quantity of a non-renewable resource during the
manufacturing process, society will eventually bear the costs for the depletion of this natural
resource. Another example of an external cost is an increase in population health effects
resulting from the emission of chemicals from a manufacturing facility. The manufacturer does
not pay for any illnesses that occur outside the plant that result from air emissions. Society must
bear these costs in the form of medical care payments or higher insuranpe premiums.
I
Conversely, external benefits are those that do not benefit the manufacturer directly. For
example, an alternative that uses less water results in both private and external benefits. The
manufacturer pays less for water; society in general benefits from less use of a scarce resource.
This type of example is why particular aspects of the MHC process are discussed in terms of
both private benefits and costs and external benefits and costs.
The potential external benefits associated with the use of an MHC alternative include:
reduced health risk for workers and the general public, reduced ecological risk, and reduced use
of energy and natural resources. Another potential externality is the influence a technology
choice has on the number of PWB plant jobs in a community. Each of these is discussed in turn
below.
DRAFT
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13. SOCIAL BENEFITS/COSTS ASSESSMENT
Table 7.13 Examples of Private Costs and Benefits Not Quantified
Description of Potential Costs or Benefits
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All of the alternatives result in the generation of sludge, off-specification PWBs, and other sol
filters. These waste streams must be recycled or disposed of, some of them as hazardous wast
manufacturers send sludges to a recycler to reclahn metals in the sludge. Sludges that cannot 1
likely have to be landfilled. It is likely that the manufacturer will incur costs in order to recyc]
other solid wastes, however these costs were not quantified. Three categories of MHC techno;
wastes, including electroless copper, conductive ink, and tin-palladium. However, other techn
considered hazardous because they exhibit certain characteristics. In addition, most facilities <
process lines prior to on-site treatment, including wastewater from electroplating operations. '
copper electroplating operations is a RCRA F006 hazardous waste. Reducing the volume and
provides social benefits.
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The cost of complying with all environmental and safety regulations affecting the MHC proce
However, chemicals and wastes from the MHC alternatives are subject to fewer overall federa
the baseline, suggesting that implementing an alternative could potentially reduce compliance
the relative cost of complying with OSHA requirements, because the alternatives pose similar
(although non-automated, non-conveyorized equipment may pose less overall process hazards
equipment).
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Based on the results of the risk characterization, it appears that alternatives to the baseline proi
human health and the environment. Implementing an alternative could cause private benefits i
insurance cost and increased employee productivity from decreases in incidences of illness. C
risk also provide social benefits (discussed hi Section 7.2.4).
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Many businesses are finding that using cleaner technologies results in less tangible benefits, si
image and improved community relations. While it is difficult to put a monetary value on the:
considered in the decision-making process.
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DRAFT
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7.2 SOCIAL BENEFITS/COSTS ASSESSMENT
Occupational Health Risks
Section 7.2.3 discussed risk characterization results for occupational exposures. Based on
the results of the risk characterization, it appears that alternatives to the non-conveyorized
electroless copper process have private benefits due to reduced occupational risks. However,
there are also occupational inhalation risk concerns for some chemicals in the non-formaldehyde
electroless copper and tin-palladium non-conveyorized processes. In addition, there are
occupational dermal exposure risk concerns for some chemicals in the conveyorized electroless
copper, non-formaldehyde electroless copper, and tin-palladium processes with conveyorized or
non-conveyorized equipment. Finally, occupational health risks could not be quantified for one
or more of the chemicals used in each of the MHC technologies. This is due to the fact that
proprietary chemicals in the baths are not included18 and to missing toxicity or chemical property
data for some chemicals known to occur in the baths.
Reduced occupational risks provide significant private as well as social benefits. Private
benefits can include reduced insurance and liability costs, which may be readily quantifiable for
an individual manufacturer. External benefits are not as easily quantifiable. They may result
from the workers themselves having reduced costs such as decreased insurance premiums or
medical payments or society having reduced costs based on the structure of the insurance
industry.
Data exist on the cost of avoiding or mitigating certain illnesses that are linked to
exposures to MHC chemicals. These cost estimates can serve as indicators of the potential
benefits associated with switching to technologies using less toxic chemicals or with reduced
exposures. Table 7.14 lists potential health effects associated with MHC chemicals of concern.
It is important to note that, except for cancer risk from formaldehyde, the risk characterization
did not link exposures of concern with particular adverse health outcomes or with the number of
incidences of adverse health outcomes.19 Thus, the net benefit of illnesses avoided by switching
to an MHC alternative cannot be calculated.
Health endpoints potentially associated with MHC chemicals of concern include: nasal
cancer (for formaldehyde), eye irritation and headaches. The draft EPA publication, The Medical
Costs of Selected Illnesses Related to Pollutant Exposure (EPA, 1996), evaluates the medical
cost of some forms of cancer, but not nasal cancer. Other publications have estimated the
economic costs associated with eye irritation and headaches. These data are discussed below.
18 Electrochemicals, LeaRonal, and Solution Technology Systems have provided information on
proprietary chemical ingredients to the project for evaluation in the risk characterization. Atotech, Enthone-OMI,
MacDermid, and Shipley have not. Risk results for proprietary chemicals, but not chemical identities or
concentrations, will be included in the final CTSA.
19 Cancer risk from formaldehyde exposure was expressed as a probability, but the exposure assessment
did not determine the size of the potentially exposed population (e.g., number of MHC line operators and others
working in the process area). This information would be necessary to estimate the number of illnesses avoided by
switching to an alternative from the baseline.
DRAFT
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7.2 SOCIAL BENEFITS/COSTS ASSESSMENT
Table 7.14 Potential Health Effects Associated with MHC Chemicals of Concern
Chemical of
Concern
Copper Chloride
Ethanolamine
2-Ethoxyethanol
Ethylene Glycol
Fluoroboric Acid
Formaldehyde
Methanol
Palladium
Palladium
Chloride
Alternatives with
Exposure Levels
of Concern
Electroless Copper
Electroless Copper,
Tin-Palladium
Electroless Copper
Electroless Copper
Electroless Copper,
Tin-Palladium
Electroless Copper
Electroless Copper
Electroless Copper,
Tin-Palladium
Tin-Palladium
Pathway
of
Concern"
inhalation
dermal
inhalation
inhalation
inhalation
dermal
inhalation
dermal
inhalation
dermal
dermal
Potential Health Effects
Long-term exposure to copper dust can irritate nose, mouth,
eyes and cause dizziness. Long-term exposure to high levels of
copper may cause liver damage. Copper is not known to cause
cancer. The seriousness of the effects of copper can be
expected to increase with both level and length of exposure.
No data were located for health effects from dermal exposure
in humans.
Ethanolamine is a strong irritant. Animal studies showed that
the chemical is an irritant to the respiratory tract, eyes, and
skin. No data were located for inhalation exposure in humans.
In animal studies 2-ethoxyethanol caused harmful blood
effects, including destruction of red blood cells and releases of
hemoglobin (hemolysis), and male reproductive effects at high
exposure levels. The seriousness of the effects of the chemical
can be expected to increase with both level and length of
exposure. No data were located for inhalation exposure in
humans.
In humans, low levels of vapors produce throat and upper
respiratory irritation. When ethylene glycol breaks down in the
body, it forms chemicals that crystallize and that can collect in
the body and prevent kidneys from working. The seriousness
of the effects of the chemical can be expected to increase with
both level and length of exposure.
Fluoroboric acid in humans produces strong caustic effects
leading to structural damage to skin and eyes.
EPA has classified formaldehyde as a probable human
carcinogen (EPA Group Bl). Inhalation exposure to
formaldehyde in animals produces nasal cancer at low levels.
In humans, exposure to formaldehyde at low levels in air
Droduces skin irritation and throat and upper respiratory
irritation. The seriousness of these effects can be expected to
increase with both level and length of exposure.
In humans, exposure to formaldehyde at low levels in air
Droduces skin irritation. The seriousness of these effects can
DC expected to increase with both level and length of exposure.
Long-term exposure to methanol vapors can cause headache,
irritated eyes and dizziness at high levels. No harmful effects
were seen when monkeys were exposed to highly concentrated
vapors of methanol. When methanol breaks down in the
tissues, it forms chemicals that can collect in the tissues or
jlood and lead to changes in the interior of the eye causing
Blindness.
No specific information was located for dermal exposure of
jalladium in humans.
Long-term dermal exposure to palladium chloride in humans
produces contact dermatitis.
DRAFT
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7.2 SOCIAL BENEFITS/COSTS ASSESSMENT
Chemical of
Concern
Sodium Chlorite
Stannous
Chloride
Sulfuric Acid
Alternatives with
Exposure Levels
of Concern
Electroless Copper,
Non-Formaldehyde
Electroless Copper
Electroless Copper,
Non-Formaldehyde
Electroless Copper,
Tin-Palladium
Electroless Copper,
Non-Formaldehyde
Electroless Copper,
Tin-Palladium
Pathway
of
Concern"
dermal
dermal
inhalation
Potential Health Effects
No specific information was located for health effects from
dermal exposure to sodium chlorite in humans. Animal studies
showed that the chemical produces moderate irritation of skin
and eyes.
Mild irritation of the skin and mucous membrane has been
shown from inorganic tin salts. However, no specific
information was located for dermal exposure to stannous
chloride in humans. Stannous chloride is only expected to be
harmful at high doses; it is poorly absorbed and enters and
leaves the body rapidly.
Sulfuric acid is a very strong acid and can cause structural
damage to skin and eyes. Humans exposed to sulfuric acid
mist at low levels in air experience a choking sensation and
irritation of lower respiratory passages.
* Inhalation concerns only apply to non-conveyorized processes. Dermal concerns may apply to non-conveyorized
and/or conveyorized processes (see Table 7.3).
Benefits of Avoiding Illnesses Potentially Linked to MHC Chemical Exposure
This section presents estimates of the economic costs of some of the illnesses or
symptoms associated with exposure to MHC chemicals. To the extent that MHC chemicals are
not the only factor contributing toward the illnesses described, individual costs may overestimate
the potential benefits to society from substituting alternative MHC technologies for the baseline
electroless copper process. For example, other PWB manufacturing process steps may also
contribute toward adverse worker health effects. The following discussion focuses on the
external benefits of reductions in illness. However, private benefits may be accrued by PWB
manufacturers through increased worker productivity and a reduction in liability and health care
insurance costs. While reductions in insurance premiums as a result of pollution prevention are
not currently widespread, the opportunity exists for changes in the future.
Exposure to several of the chemicals of concern is associated with eye irritation. Other
potential health effects include headaches and dizziness. The economic literature provides
estimates of the costs associated with eye irritation and headaches. An analysis by Unsworth
and Neumann summarizes the existing literature on the costs of illness based on estimates of how
much an individual would be willing to pay to avoid certain acute effects for one symptom day
(Unsworth and Neumann, 1993). These estimates are based upon a survey approach designed to
elicit estimates of individual willingness-to-pay to avoid a single incidence and not the lifetime
costs of treating a disease. Table 7.15 presents a summary of the low, mid-range, and high
estimates of individual willingness-to-pay to avoid eye irritation and headaches. These estimates
provide an indication of the benefit per affected individual that would accrue to society if
switching to a substitute MHC technology reduced the incidence of these health endpoints.
DRAFT
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7.2 SOCIAL BENEFITS/COSTS ASSESSMENT
Table 7.15 Estimated Willingness-to-Pay to Avoid Morbidity Effects for
One Symptom Day (1995 dollars)
Health Endpoint
Eye Irritation*
Headache6
Low
$21
$2
Mid-Range
$21
$13
High
$46
$67
Tolley, G.S., et al. January 1986. Valuation of Reductions in Human Health Symptoms and Risks. University of
Chicago. Final Report for the U.S. EPA. As cited in Unsworth, Robert E. and James E. Neumann, Industrial
Economics, Incorporated. Memorandum to Jim DeMocker, Office of Policy Analysis and Review. Review of
Existing Value of Morbidity Avoidance Estimates: Draft Valuation Document. September 30,1993.
b Dickie, M, et al. September 1987. Improving Accuracy and Reducing Costs of Environmental Benefit
Assessments. U.S. EPA, Washington, DC. Tolley, G.S., et al. Valuation of Reductions in Human Health Symptoms
and Risks. January 1986. University of Chicago. Final Report for the U.S. EPA. As cited in Unsworth, Robert E.
and James E. Neumann, Industrial Economics, Incorporated. Memorandum to Jim DeMocker, Office of Policy
Analysis and Review. Review of Existing Value of Morbidity Avoidance Estimates: Draft Valuation Document.
September 30, 1993.
Public Health Risk
Section 7.2.3 discussed public health risks from MHC chemical exposure. The risk
characterization identified no concerns for the general public through ambient air exposure with
the possible exception of formaldehyde exposure from electroless copper processes. While the
study found little difference among the alternatives for those public health risks that were
assessed, it was not within the scope of this comparison to assess all community health risks.
Risk was not characterized for exposure via other pathways (e.g., drinking water, fish ingestion,
etc.) or short-term exposures to high levels of hazardous chemicals when there is a spill, fire, or
other periodic release.
Ecological Hazards
The CTSA evaluated the ecological risks of the baseline and alternatives in terms of
aquatic toxicity hazards. Aquatic risk could not be estimated because chemical concentrations in
MHC line effluents and streams were not available and could not be estimated. Reduced aquatic
hazards can provide significant external benefits, including improved ecosystem diversity,
improved supplies for commercial fisheries, and improved recreational values of water resources.
There are well documented aquatic toxicity problems associated with copper discharges to
receiving waters, but this assessment was unable to determine the relative reduction in copper or
other toxic discharges from the baseline to the alternatives. Five processes contain copper
sulfate, the most toxic of the copper compounds found in MHC lines, and other processes contain
copper chloride. In order to evaluate the private and external benefits or costs of implementing
an alternative, PWB manufacturers should attempt to determine what the changes in their mass
loading of copper or other toxic discharges would be.20
20 Copper dispharges are a particular problem because of the cumulative mass loadings of copper
discharges from a number of different industry sectors, including the PWB industry.
DRAFT
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7.2 SOCIAL BENEFITS/COSTS ASSESSMENT
Energy and Natural Resources Consumption
Table 7.16 summarizes the water and energy consumption rates and percent changes in
consumption from the baseline to the MHC alternatives. All of the alternatives use substantially
less energy and water per ssf of PWB produced, with the exception of the carbon technology
which only has a slight decrease (< ten percent) in energy use from the baseline. While
manufacturers face direct costs from the use of energy and water in the manufacturing process,
society as a whole also experiences costs from this usage. For energy consumption, these types
of externalities can come in the form of increased emissions to the air either during the initial
manufacturing of the energy or the MHC processes themselves. These emissions include CO2,
SOX, NO2, CO, H2SO4, and particulate matter. Table 5.9 in the Energy Impacts section (Section
5.2) details the pollution resulting from the generation of energy consumed by MHC alternatives.
Environmental and human health concerns associated with these pollutants include global
warming, smog, acid rain, and health effects from toxic chemical exposure.
Table 7.16 Energy and Water Consumption of MHC Technologies
MHC Technology
Electroless Copper, non-conveyorized (BASELINE)
Electroless Copper, conveyorized
Carbon, conveyorized
Conductive Polymer, conveyorized
Graphite, conveyorized
Non-Formaldehyde Electroless Copper, non-conveyorized
Organic-Palladium, non-conveyorized
Organic-Palladium, conveyorized
Tin-Palladium, non-conveyorized
Tin-Palladium, conveyorized
Water
Consumption
gal/ssf
11.7
1.15
1.29
0.73
0.45
3.74
1.35
1.13
1.80
0.57
% change
-90
-89
-94
-96
-68
-88
-90
-85
-95
Energy
Consumption
Btu/ssf
573
138
514
94.7
213
270
66.9
148
131
96.4
% change
-76
- 9.6
-83
-63
-53
-88
-74
-77
-83
In addition to increased pollution, the higher energy usage of the baseline also results in
external costs in the form of depletion of natural resources. Some form of raw resource is
required to make electricity, whether it be coal, natural gas or oil, and these resources are non-
renewable. While it is true that the price of the electricity to the manufacturer takes into account
the actual raw materials costs, the price of electricity does not take into account the depletion of
the natural resource base. As a result, eventually society will have to bear the costs for the
depletion of these natural resources.
The use of water and consequent generation of wastewater also results in external costs to
society. While the private costs of this water usage are included in the cost estimates in Table
7.10, the external costs are not. The private costs of water usage account for the actual quantities
of water used in the MHC process by each different technology. However, clean water is quickly
becoming a scarce resource, and activities that utilize water therefore impose external costs on
society. These costs can come in the form of higher water costs for the surrounding area or for
higher costs paid to treatment facilities to clean the water. These costs may also come in the
DRAFT
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7.2 SOCIAL BENEFITS/COSTS ASSESSMENT
form of decreased water quality available to society. In fact, in Germany, PWB manufacturers
are required to use their wastewater at least three times before disposing of it because of the
scarcity of water.
Effects on Jobs
The results of the cost analysis suggest that alternative MHC technologies are generally
more efficient than the baseline process due to decreased cycle times. In addition, labor costs are
one of the biggest factors causing the alternatives to be cheaper. Neither the Cost Analysis nor
the GTS A analyzed the potential for job losses resulting from implementing an alternative.
However, if job losses were to occur, this could be a significant external cost to the community.
For example, in Silicon Valley, community groups are striving to retain clean, safe jobs through
directing cost savings to environmental improvements that create or retain jobs. While the
effects on jobs of wide-scale adoption of an alternative were not analyzed, anecdotal evidence
from facilities that have switched from the baseline suggests that jobs are not lost, but workers
are freed to work on other tasks (Keenan, 1997). In addition, one incentive for PWB
manufacturers to invest in the MHC alternatives is the increased production capacity of the
alternatives. Some PWB manufacturers who choose to purchase new capital-intensive
equipment are doing so because of growth, and would not be expected to lay off workers
(Keenan, 1997).
Qther External Benefits or Costs
In addition to the externalities discussed above, the baseline and MHC alternatives can
have other external benefits and costs. Many of these were discussed in Table 7.13 because
many factors share elements of both private and external benefits and costs. For example,
regulated chemicals result in a compliance cost to industry, but they also result in an enforcement
cost to society whose governments are responsible for ensuring environmental requirements are
met.
7.2.5 Summary of Benefits and Costs
The objective of a social benefits/costs assessment is to identify those technologies or
decisions that maximize net benefits. Ideally, the analysis would quantify the social benefits and
costs of using the alternative and baseline MHC technologies in terms of a single unit (e.g.,
dollars) and calculate the net benefits of using an alternative instead of the baseline technology.
Due to data limitations, however, this assessment presents a qualitative description of the
benefits and costs associated with each technology compared to the baseline. Table 7.17
compares some of the relative benefits and costs of each technology to the baseline, including
production costs, worker health risks, public health risks, aquatic toxicity concerns, water
consumption, and energy consumption. The effects on jobs of wide-scale adoption of an
alternative are not included in the table because the potential for job losses was not evaluated in
the CTSA. However, the results of the Cost Analysis suggest there are significantly reduced
labor requirements for the alternatives. Clearly, the loss of manufacturing jobs would be a
significant external cost to the community and should be considered by PWB manufacturers
when choosing an MHC technology.
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7.2 SOCIAL BENEFITS/COSTS ASSESSMENT
31
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ill
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m
t~-
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bon, conveyorized
C
ed
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Graphite, conveyorized
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-Formaldehyde Elec
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7-35
DRAFT
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7.2 SOCIAL BENEFITS/COSTS ASSESSMENT
While each alternative presents a mixture of private and external benefits and costs, it
appears that each of the alternatives have social benefits as compared to the baseline. In
addition, at least three of the alternatives appear to have social benefits over the baseline in every
category, but public health risk. These are the conveyorized conductive polymer process and
both conveyorized and non-conveyorized organic-palladium processes. However, the supplier of
these technologies has declined to provide information on proprietary chemical ingredients for
evaluation in the risk characterization. Little or no improvement is seen in public health risks
because concern levels were very low for all technologies, although formaldehyde cancer risks as
high as from 1 x 10'7 to 3 x 10~7 were estimated for non-conveyorized and conveyorized
electroless copper processes, respectively.
In terms of worker health risks, conveyorized processes have the greatest benefits for
reduced worker inhalation exposure to bath chemicals; they are enclosed and vented to the
atmosphere. However, dermal contact from bath maintenance activities can be of concern
regardless of the equipment configuration for electroless copper and tin-palladium processes. No
data were available for conveyorized non-formaldehyde electroless copper processes (the same
chemical formulations were assumed), but the non-conveyorized version of this technology also
has chemicals with dermal contact concerns.
The relative benefits and costs of technologies from changes in aquatic toxicity concerns
was more difficult to assess because only aquatic hazard was evaluated and not risk. Several of
the technologies contain copper sulfate, which has a very low aquatic toxicity concern
concentration (0.00002 mg/1). However, all of the technologies contain other chemicals with
high aquatic toxicity concern levels, although these chemicals are not as toxic as copper sulfate.
All of the alternatives provide significant social benefits in terms of energy and water
consumption, with the exception of energy consumption for the carbon technology. The drying
ovens used with this technology cause this technology to consume nearly as much energy per ssf
as the baseline.
DRAFT
7-36
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7.3 TECHNOLOGY SUMMARY PROFILES
7.3 TECHNOLOGY SUMMARY PROFILES
This section of the CTSA presents summary profiles of each of the MHC technologies.
The profiles summarize key information from various sections of the CTSA, including the
following:
Generic process steps, typical bath sequences and equipment configurations evaluated in
the CTSA.
Human health and environmental hazards data and risk concerns for non-proprietary
chemicals.
Production costs and resource (water and energy) consumption data.
Federal environmental regulations affecting chemicals in each of the technologies.
The conclusions of the social benefits/costs assessment.
The first summary profile (Section 7.3.1) presents data for both the baseline process and
the conveyorized electroless copper process. Sections 7.3.2 through 7.3.7 present data for the
carbon, conductive polymer, graphite, non-formaldehyde electroless copper, organic-palladium,
and tin-palladium technologies, respectively.
As discussed in Section 7.2, each of the alternatives appear to provide private as well as
external benefits compared to the non-conveyorized electroless copper process (the baseline
process), though net benefits could not be assessed without a more thorough assessment of
effects on jobs and wages. However, the actual decision of whether or not to implement an
alternative occurs outside of the CTSA process. Individual decision-makers may consider a
number of additional factors, such as their individual business circumstances and community
characteristics, together with the information presented in this CTSA.
7.3.1 Electroless Copper Technology
Generic Process Steps and Typical Bath Sequence
1
u
1
L»
Cleaner/ |_^
Conditioner 1 *
Catalyst |__^.
•Water Rinse x2|— >
Water Rinse x 2| — >•
Water Rinse x2| — ^
Acid Dip 1 ^.
Microetch I — >
Accelerator 1 — ^
Water Rinse 1 — >•
Water Rinse x 2 1— ^
Water Rinse I — ^
Anti-Tarnish 1 — ^
Predip 1— ,
1
J Electroless b
" Copper ri
1
H Water Rinse 1
Equipment Configurations Evaluated: Nbn-conveyorized (the baseline process) and
conveyorized.
DRAFT
7-37
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7.3 TECHNOLOGY SUMMARY PROFILES
Risk Characterization
Table 7.18 summarizes human and environmental hazards and risk concerns for non-
proprietary chemicals in the electroless copper technology. The risk characterization identified
occupational inhalation risk concerns for seven chemicals in non-conveyorized electroless copper
processes and dermal risk concerns for six chemicals for either equipment configuration.
However, no toxicity values are available for some chemicals. No public health risk concerns
were identified for the pathways evaluated, although formaldehyde cancer risks as high as
1 x 10~7 and 3 x 10~7 were estimated for non-conveyorized and conveyorized electroless copper
processes, respectively.
Table 7.18 Summary of Human Health and Environmental Hazard Data and Risk
Concerns for the Electroless Copper Technology
Chemical"
Ammonium Chloride
Benzotriazole
Boric Acid
Copper (I) Chloride8
Copper Sulfate*
Dimethylaminoborane
Dimethylformamide
Ethanolamine
2-Ethoxyethanol
ithylenediaminetetraacetic
Acid(EDTA)
Ethylene Glycol
Pluoroboric Acid
Formaldehyde
Formic Acid
Hydrochloric Acid1
Hydrogen Peroxide
Hydroxyacetic Acid
Isopropyl Alcohol; or
2-Propanol
m-Nitrobenzene Sulfonic
Acid
Magnesium Carbonate
Human Health Hazard and Occupational
Risks'3 :
Inhalation'
Toxicity*
(mg/ro*)
ND
ND
ND
0.6
(LOAEL)
ND
ND
0.03 (RfC)
12.7
(LOAEL)
0.2 (RfC)
ND
31
ND
0.1 ppm
(LOAEL)
59.2
(NOAEL)
0.007 (RfC)
79
ND
980
(NOAEL)
ND
Risk
Concerns
NA
NE
NE
yes
NE
NE
no
yes
yes
ND
yes
NE
yes
no
no
no
NE
no
NE
Dermal11
Toxicity*
(mg/kg-d)
1691 (NOAEL)
109 (LOAEL)
62.5 (LOAEL)
0.07 (LOAEL)
ND
ND
125 (LOAEL)
320 (NOAEL)
0.4 (RfD)
ND
2 (RfD)
0.77
0.2 (RfD)
ND
ND
630 (NOAEL)
250 (NOAEL)
100 (NOAEL)
ND
Risk
Concerns
no
no
no
yes
NE
NE
no
no
no
NE
no
yes
yes
NE
NEk
no
no
no
NE
Generally regarded as safe (U.S. FDA as cited in
HSDB, 1995)
Carcinogenicity
Weight-of-
Evidence
Classification
none
none
none
EPA Class D
none
none
IARC Group 2B1
none
none
none
none
none
EPA Class Bl
IARC Group 2A
none
IARC Group 3
IARC Group 3
none
none
none
none
A*p*Hc
TMicity
€C
(m
-------
7.3 TECHNOLOGY SUMMARY PROFILES
Chemical*
Methanol
Palladium
Peroxymonosulfuric Acid
Potassium Bisulfate
Potassium Cyanide
Potassium Hydroxide
Potassium Persulfate
Potassium Sodium
Tartrate
Potassium Sulfate
Sodium Bisulfate
Sodium Carbonate
Sodium Chlorite
Sodium Cyanide
Sodium Hydroxide
Sodium Hypophosphite
Sodium Sulfate
Stannous Chloride
Sulfuric Acid
Tartaric Acid
p-Toluene Sulfonic Acid
Triethanolamine
Human Health Hazard and Occupational
Risks"
Inhalation'
Toxk%c
(rng/itt*)
1,596-
10,640
ND
ND
ND
ND
7.1
ND
Risk
Concerns
yes
NA
NA
NE
NE
no
NE
Dermal*
Texicity6
(mg/kg-d)
0.5 (RfD)
0.95 (LOAEL)
ND
ND
0.05 (RfD)
ND
ND
Risk
Concerns
no
yes
NE
NE
no
NE
NE
Generally regarded as safe (U.S. FDA as cited in
HSDB, 1996)
15(TCLO)
ND
10
(NOAEL)
ND
ND
2 (LOAEL)
ND
ND
ND
0.066
(NOAEL)
ND
ND
ND
no
NA
no
NA
NE
no
NA
NA
NA
yes
NE
NA
NA
ND
ND
ND
10 (NOAEL)
0.04 (RfD)
ND
ND
420 (NOAEL)
0.62 (RfD)
ND
8.7
ND
32 (LOAEL)
NE
NE
NE
yes
no
NE
NE
no
yes
NEk
no
ND
no
Carcinogenicity
WeSgfct-of-
Evidence
Classification
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
Aquatic
Toxfcity
CC
Ciagfl)
17
0.00014
0.030h
>1.0h
0.79
0.08
0.92
ND
0.11
0.058
2.4
0.00016
0.79
2.5
0.006h
0.81
0.0009
2.0
1.0
1.0"
0.18
a Chemicals in bold were in all electroless copper technologies evaluated, unless otherwise noted.
b Risk concerns are for MHC line operators (the most exposed individual).
c Inhalation risk concerns for non-conveyorized process only. Inhalation risk from fully enclosed, conveyorized
process is assumed to be negligible.
d Dermal risk concerns apply to both conveyorized and non-conveyorized equipment.
e Toxicity measure is RfC, RfD, NOAEL, or LOAEL as indicated. If not indicated, the type of toxicity measure
was not specified in the available information, but assumed to be LOAEL in risk calculations.
f Estimated using ECOSAR computer software, based on structure-activity relationship.
g Either copper (I) chloride or copper sulfate was in all electroless copper lines evaluated.
h Estimated by EPA's Structure-Activity Team.
' Cancer risk was not evaluated because no slope (unit risk) factor is available.
j Hydrochloric acid was listed on the MSDSs for five of six electroless copper lines.
k Chronic dermal toxicity data are not typically developed for strong acids.
ND: No Data. No toxicity measure available for this pathway.
NE: Not Evaluated, due to lack of toxicity measure.
NA: Not Applicable. Inhalation exposure level was not calculated because the chemical is not volatile (vapor
pressure below 1 x 10~3 torr) and is not used in any air-sparged bath.
DRAFT
7-39
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7.3 TECHNOLOGY SUMMARY PROFILES
Performance
The performance of the electroless copper technology was demonstrated at seven test
facilities, including six sites using non-conveyorized equipment and one site using conveyorized
equipment. Performance test results were not differentiated by the type of equipment
configuration used. The Performance Demonstration determined that each of the alternative
technologies has the capability of achieving comparable levels of performance to electroless
copper.
Production Costs and Resource Consumption
Computer simulation was used to model key operating parameters, including the time
required to process a job consisting of 350,000 ssf and the amount of resources (water and
energy) consumed. This information was used with a hybrid cost model of traditional cost (i.e.,
capital costs, etc.) and activity-based costs to determine average manufacturing costs per ssf and
water and energy consumption per ssf. Average manufacturing costs for the baseline process
(the non-conveyorized electroless copper process) were $0.51/ssf, while water and energy
consumption were 11.7 gal/ssf and 573 Btu/ssf, respectively. However, the conveyorized
electroless copper process consumed less water and energy and was more cost-effective than the
baseline process (non-conveyorized electroless copper). Figure 7.1 lists the results of the
production costs and resource consumption analyses for the conveyorized electroless copper
process and illustrates the percent changes in costs and resource consumption from the baseline.
Manufacturing costs, water consumption, and energy consumption are less than the baseline by
71 percent, 90 percent, and 76 percent, respectively.
Regulatory Concerns
Chemicals contained in the electroless copper technology are regulated by the Clean
Water Act, the Safe Drinking Water Act, the Clean Air Act, the Superfund Amendments and
Reauthorization Act, the Emergency Planning and Community Right-to-Know Act, and the
Toxic Substances Control Act. In addition, the technology generates wastes listed as hazardous
(P or U wastes) under RCRA.
Social Benefits arid Costs
A qualitative assessment of the private and external (e.g., social) benefits and costs of the
baseline and alternative technologies was performed to determine if there would be net benefits
to society if PWB manufacturers switched to alternative technologies from the baseline. It was
concluded that all of the alternatives, including the conveyorized electroless copper process,
appear to have net societal benefits, though net benefits could not be completely assessed without
a more thorough assessment of effects on jobs and wages. For the conveyorized electroless
copper process this is due to reduced occupational inhalation risk as well as to lower production
costs and to reduced consumption of limited resources (water and energy).
DRAFT
7-40
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7.3 TECHNOLOGY SUMMARY PROFILES
Figure 7.1 Production Costs and Resource Consumption of Conveyorized Electroless
Copper Technology
(Percent Change from Baseline with Actual Values in Parentheses)
-100
Conveyorized
Production Costs
Energy Consumption
Water Consumption
7.3.2 Carbon Technology
Generic Process Steps and Typical Bath Sequence
1
L
^^
i
L
Plnnnor 1 ^k. Water RlTlSC • ^-
. Water Rinse 1
Carbon Black 1 ^^ Air K"nife/Drv 1
Equipment Configurations Evaluated: Conveyorized.
7-41
DRAFT
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7.3 TECHNOLOGY SUMMARY PROFILES
Risk Characterization
Table 7.19 summarizes human and environmental hazards and risk concerns for non-
proprietary chemicals in the carbon technology. The risk characterization identified no human
health risk concerns for the pathways evaluated. However, proprietary chemicals are not
included in this assessment and no toxicity data are available for some chemicals in carbon
technology baths.
Table 7.19 Summary of Human Health and Environmental Hazard Data and Risk
Concerns for the Carbon Technology
Chemical*
Carbon Black
Copper Sulfate
Ethanolamine
Ethylene Glycol
Potassium Carbonate
Potassium Hydroxide
Sodium Persulfate
Sulfuric Acid
Human Health Hazard and Occupational
Risksh
Inhalation'
Toxicity4
(mg/m3)
7.2 (LOAEL)
ND
12.7 (LOAEL)
31
ND
7.1
ND
0.066 (NOAEL)
Dermal
Toxicityd
(mg/kg"d)
ND
ND
320 (NOAEL)
2(RfD)
ND
ND
ND
ND
Risk
Concerns
NE
NE
no
no
NEe
NE
NE
NEf
Careinogeniicity
Weight-^
Evidence
Classification
IARC 2B
none
none
none
none
none
none
none
Aquatic
Toxicity
CC i
(ittgrt)
ND
0.00002
0.075
3.3
>3.0
0.08
0.065
2.0
Only one carbon technology was evaluated. All chemicals listed were present in that product line.
b Risk evaluated for conveyorized process only. Risk concerns are for line operator (the most exposed individual).
c Exposure and risk not calculated. Inhalation exposure and risk from fully enclosed, conveyorized process is
assumed to be negligible.
A Toxicity measure is RfC, RfD, NOAEL, or LOAEL, as indicated. If not indicated, the type of toxicity measure
was not specified in the available information, but assumed to be a LOAEL in risk calculations.
* Chemical has very low skin absorption (based on EPA's Structure-Activity Team evaluation); risk from dermal
exposure not expected to be of concern.
f Chronic dermal toxicity data are not typically developed for strong acids.
ND: No Data. No toxicity measure available for this pathway.
NE: Not Evaluated, due to lack of toxicity measure.
Performance
The performance of the carbon technology was demonstrated at two test facilities. The
Performance Demonstration determined that this technology has the capability of achieving
comparable levels of performance to electroless copper.
DRAFT
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7.3 TECHNOLOGY SUMMARY PROFILES
Production Costs and Resource Consumption
Computer simulation was used to model key operating parameters, including the time
required to process a job consisting of 350,000 ssf and the amount of resource (water and energy)
consumed. This information was used with a hybrid cost model of traditional costs (i.e., capital
costs, etc.) and activity-based costs to determine average manufacturing costs per ssf and water
and energy consumption per ssf. The conveyorized carbon technology consumed less water and
energy and was more cost-effective than the baseline process (non-conveyorized electroless
copper). Figure 7.2 lists the results of these analyses and illustrates the percent changes in costs
and resources consumption from the baseline. Manufacturing costs, water consumption, and
energy consumption are less than the baseline by 65 percent, 89 percent, and 9.6 percent,
respectively. J
Figure 7.2 Production Costs and Resource Consumption of Carbon Technology
(Percent Change from Baseline with Actual Values in Parentheses)
-20
£
« -40
I
-60
-80
-100-
(1.29 gal/ssf)
Production Costs
Energy Consumption
1
Conveyorized
|| Water Consumption
Regulatory Concerns
Chemicals contained in the carbon technology are regulated by the Clean Water Act, the
Safe Drinking Water Act, the Clean Air Act, the Superfund Amendments and Reauthorization
Act, and the Emergency Planning and Community Right-to-Know Act. The technology does not
generate wastes listed as hazardous (P or U waste) under RCRA, but some wastes may have
RCRA hazardous characteristics.
DRAFT
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7.3 TECHNOLOGY SUMMARY PROFILES
Social Benefits and Costs
A qualitative assessment of the private and external benefits and costs of this technology
suggests there would be net benefits to society if PWB manufacturers switched to the carbon
technology from the baseline. Among other factors, this is due to lower occupational risks to
workers and to reduced consumption of limited resources (water and, to a lesser degree, energy).
7.3.3 Conductive Polymer Technology
1
u
Microetch 1 — ^-
Water Rinse x 2| — ^
Water Rinse x si— >•
Conductive | ^
Polymer |
Cleaner/ 1 ^
C onditionerl
Water Rinse x 2 1 ^
Water Rinse x si ^.
Microetch 1 — ^.
Catalyst 1
Copper Flash 1
Equipment Configurations Evaluated: Conveyorized.
Risk Characterization
Table 7.20 summarizes human and environmental hazards and risk concerns for non-
proprietary chemicals in the conductive polymer technology. The risk characterization identified
no human health risk concerns for the pathways evaluated. However, proprietary chemicals are
not included hi this assessment and no toxicity data are available for some chemicals in
conductive polymer technology baths.
Performance
The performance of the conductive polymer technology was demonstrated at one test
facility. The Performance Demonstration determined that this technology has the capability of
achieving comparable levels of performance to electroless copper.
Production Costs and Resource Consumption
Computer simulation was used to model key operating parameters, including the tune
required to process a job consisting of 350,000 ssf and the amount of resources (water and
energy) consumed. This information was used with a hybrid cost model of traditional costs (i:e.,
capital costs, etc.) and activity-based costs to determine average manufacturing costs per ssf and
water and energy consumption per ssf.
The conveyorized conductive polymer technology consumed less water and energy than
the baseline process (non-conveyorized electroless copper). Figure 7.3 lists the results of these
analyses and illustrates the percent changes in resources consumption from the baseline.
Manufacturing costs, water consumption, and energy consumption are less than the baseline by
82 percent, 94 percent, and 83 percent, respectively.
DRAFT
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7,3 TECHNOLOGY SUMMARY PROFILES
Table 7.20 Summary of Human Health and Environmental Hazard Data and Risk
Concerns for the Conductive Polymer Technology
Chemical1'
IH-Pyrrole
Peroxymonosulfuric Acid
Phosphoric Acid
Sodium Carbonate
Sodium Hydroxide
Sulfuric Acid
Human Health Hazard and Occupational
Risks*
Inhalation4
Toxicity*
(mg/mj)
ND
ND
ND
10(NOAEL)
2 (LOAEL)
0.066 (NOAEL)
Dermal
Toxicity*
(mg/kg-d)
ND
NDe
ND
ND
ND
ND
Risk
Concerns
NE
ND
NEf
NE
NE
NEf
Carcinogenicity
Weight-Of
Evidence
Classification
none
none
none
none
none
none
Aquatic
Toxieity
CC
(mgrt)
0.21
0.030
0.138
2.4
2.5
2.0
Only one conductive polymer technology was evaluated. All chemicals were present in that product line.
b Risk evaluated for conveyorized process only. Risk concerns are for line operator (the most exposed individual).
c Exposure and risk not calculated. Inhalation exposure and risk from fully enclosed, conveyorized process is
assumed to be negligible.
d Toxicity measure is RfC, RfD, NOAEL, or LOAEL, as indicated. If not indicated, the type of toxicity measure
was not specified in the available information, but assumed to be a LOAEL in risk calculations.
e Chemical has very low skin absorption (based on EPA's Structure-Activity Team evaluation); risk from dermal
exposure not expected to be of concern.
f Chronic dermal toxicity data are not typically developed for strong acids.
ND: No Data. No toxicity measure available for this pathway.
NE: Not Evaluated, due to lack of toxicity measure.
Figure 7.3 Production Costs and Resource Consumption of Conductive Polymer Technology
(Percent Change from Baseline with Actual Values in Parentheses)
-100
Production Costs
Energy Consumption
Conveyorized
| Water Consumption
7-45
DRAFT
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7.3 TECHNOLOGY SUMMARY PROFILES
Regulatory Concerns
Chemicals contained in the conductive polymer technology are regulated by the Clean
Water Act, the Clean Air Act, and the Emergency Planning and Community Right-to-Know Act.
The technology does not generate wastes listed as hazardous (P or U waste) under RCRA, but
some wastes may have RCRA hazardous characteristics.
Social Benefits and Costs
A qualitative assessment of the private and external benefits and costs of this technology
suggests there would be net benefits to society if PWB manufacturers switched to the conductive
polymer technology from the baseline. Among other factors, this is due to lower occupational
risks to workers and to reduced consumption of limited resources (water and energy).
7.3.4 Graphite Technology
Generic Process Steps and Typical Bath Sequence
i
L>
Cleaner/ | U Water Rinse |— >•
Conditioner | ^\_ \
•i Microetch 1— >• Water Rinse x 2 1
Graphite 1 — >- Fixer (optional)l— >• Air Knife/Dry 1
\
Equipment Configurations Evaluated: Conveyorized.
Risk Characterization
Table 7.21 summarizes human and environmental hazards and risk concerns for non-
proprietary chemicals in the graphite technology. The risk characterization identified no human
health risk concerns for the pathways evaluated. However, proprietary chemicals are not included
in this assessment and no toxicity data are available for some chemicals in graphite technology
baths.
Performance
The performance of the graphite technology was demonstrated at three test facilities. The
Performance Demonstration determined that this technology has the capability of achieving
comparable levels of performance to electroless copper.
DRAFT
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7.3 TECHNOLOGY SUMMARY PROFILES
Table 7.21 Summary of Human Health and Environmental Hazard Data and Risk
Concerns for the Graphite Technology
Chemical2
Ammonia
Copper Sulfate; or
Cupric Sulfate
Ethanolamine
Graphite
Peroxymonosulfuric Acid
Potassium Carbonate
Sodium Persulfate
Sulfuric Acid
Human Health Hazard and Occupational
Risks1'
Inhalation0
Toxicity"
(mg/m3)
0.1 (RfC)
ND
12.7 (LOAEL)
56 (LOAEL)
ND
ND
ND
0.066 (NOAEL)
Derma)
Toxicit/
(mg/kg-d)
ND
ND
320 (NOAEL)
ND
NDf
NDf
ND
ND
Risk
Concerns
NE
NE
no
NE
NE
NE
NE
NEh
Carcinogenicity
Weight-of
Evidence
Classification
none
none
none
none
none
none
none
none
Aquatic
Toxicity
CC
(mg/1)
0.0042
0.00002
0.075
NDe
0.030s
>3.0
0.065
2.0
a Chemicals in bold were in both graphite technologies evaluated.
b Risk evaluated for conveyorized process only. Risk concerns are for line operator (the most exposed individual).
c Exposure and risk not calculated. Inhalation exposure and risk from fully enclosed, conveyorized process is
assumed to be negligible.
d Toxicity measure is RfC, RfD, NOAEL, or LOAEL, as indicated. If not indicated, the type of toxicity measure
was not specified in the available information.
e Not expected to be toxic at saturation levels (based on EPA Structure-Activity Team evaluation).
f Chemical has very low skin absorption (based on EPA's Structure-Activity Team evaluation); risk from dermal
exposure not expected to be of concern.
« Estimated by EPA's Structure-Activity Team.
h Chronic toxicity data are not typically developed for strong acids.
ND: No Data; no toxicity measure available for this pathway.
NE: Not Evaluated, due to lack of toxicity measure.
Production Costs and Resource Consumption
Computer simulation was used to model key operating parameters, including the time
required to process a job consisting of 350,000 ssf and the amount of resources (water and
energy) consumed. This information was used with a hybrid cost model of traditional costs (i.e.,
capital costs, etc.) and activity-based costs to determine average manufacturing costs per ssf and
water and energy consumption per ssf. The conveyorized graphite technology consumed less
water and energy and was more cost-effective than the baseline process (non-conveyorized
electroless copper). Figure 7.4 lists the results of these analyses and illustrates the percent
changes in costs and resource consumption from the baseline. Manufacturing costs, water
consumption, and energy consumption are less than the baseline by 57 percent, 96 percent, and 63
percent, respectively.
DRAFT
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7.3 TECHNOLOGY SUMMARY PROFILES
Figure 7.4 Production Costs and Resource Consumption of Graphite Technology
(Percent Change from Baseline with Actual Values in Parentheses)
-100
Conveyorized
Production Costs
Energy Consumption
Water Consumption
Regulatory Concerns
Chemicals contained in the graphite technology are regulated by the Clean Water Act, the
Safe Drinking Water Act, the Clean Air Act, the Superfund Amendments and Reauthorization
Act, and the Emergency Planning and Community Right-to-Know Act. The technology does not
generate wastes listed as hazardous (P or U waste) under RCRA, but some wastes may have
RCRA hazardous characteristics.
Social Benefits and Costs
A qualitative assessment of the private and external benefits and costs of this technology
suggests there would be net benefits to society if PWB manufacturers switched to the carbon
technology from the baseline. Among other factors, this is due to lower occupational risks to
workers and to reduced consumption of limited resources (water and energy).
DRAFT
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7.3 TECHNOLOGY SUMMARY PROFILES
7.3.5 Non-Formaldehyde Electroless Copper Technology
Generic Process Steps and Typical Bath Sequence
Electroless Copper/!
Copper Flash
Equipment Configurations Evaluated: Non-conveyorized.
Risk Characterization
Table 7.22 summarizes human and environmental hazards and risk concerns for non-
proprietary chemicals hi the non-formaldehyde electroless copper technology. The risk
characterization identified occupational inhalation risk concerns for one chemical and dermal risk
concerns for two chemicals. No public health risk concerns were identified for the pathways
evaluated. However, proprietary chemicals are not included in this assessment and no toxicity
values are available for some chemicals.
Performance
The performance of the non-formaldehyde electroless copper technology was
demonstrated at two test facilities. The Performance Demonstration determined that this
technology has the capability of achieving comparable levels of performance to electroless
copper.
Production Costs and Resource Consumption
Computer simulation was used to model key operating parameters, including the time
required to process a job consisting of 350,000 ssf and the amount of resources (water and
energy) consumed. This information was used with a hybrid cost model of traditional costs (i.e.,
capital costs, etc.) and activity-based costs to determine average manufacturing costs per ssf and
water and energy consumption per ssf. The non-conveyorized non-formaldehyde electroless
copper process consumed less water and energy and was more cost-effective than the baseline
process (non-conveyorized electroless copper). Figure 7.5 lists the results of these analyses and
illustrates the percent changes in costs and resource consumption from the baseline.
Manufacturing costs, water consumption, and energy consumption are less than the baseline by 22
percent, 68 percent, and 53 percent, respectively.
DRAFT
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7.3 TECHNOLOGY SUMMARY PROFILES
Table 7.22 Summary of Human Health and Environmental Hazard Data and Risk
Concerns for the Non-Formaldehyde Electroless Copper Technology
Chemical"
Copper Sulfate
Hydrochloric Acid
Hydrogen Peroxide
Isopropyl Alcohol; or
2-Propanol
Potassium Hydroxide
Potassium Persulfate
Sodium Chlorite
Sodium Hydroxide
Stannous Chloride
Sulfuric Acid
Human Health Hazard and Occupational
Risks"
Inhalation
Toxicity'
(mg/m3)
ND
0.007 (RfC)
79
980
(NOAEL)
7.1
ND
ND
2 (LOAEL)
ND
0.066 (NOAEL)
Risk
Concerns
NE
NA
no
no
no
NE
NA
no
NA
yes
Dermal
Toxicity0
(mg/kg-d)
ND
NDd
630 (NOAEL)
100
(NOAEL)
ND
ND
10 (NOAEL)
ND
0.62 (RfD)
NDd
Risk
Concerns
NE
NE
no
no
NE
NE
yes
ND
yes
NE
Carcinogenieity
Weight-of"
Evidence
Classification
none
IARC Group 3
IARC Group 3
none
none
none
none
none
none
none
Aquatic
Toxicity
CC
Ottg/1)
0.00002
0.1
1.2
9.0
0.08
0.92
0.00016
2.5
0.0009
2.0
* Only one non-formaldehyde electroless copper technology was evaluated. All chemicals listed were present in that
product line.
b Risk evaluated for non-conveyorized process only. Inhalation risk from fully enclosed, conveyorized process is
assumed to be low. Risk concerns are for line operator (the most exposed individual).
e Toxicity measure is RfC, RfD, NOAEL, or LOAEL, as indicated. If not indicated, the type of toxicity measure
was not specified in the available information, but assumed to be a LOAEL in risk calculations.
* Chronic toxicity data are not typically available for strong acids.
ND: No Data; no toxicity measure developed for this pathway.
NE: Not Evaluated, due to lack of toxicity measure.
NA: Not Applicable; inhalation exposure level was not calculated because the chemical is not volatile (vapor
pressure below 1 x 10'3 torr) and is not used in any air-sparged bath.
Regulatory Concerns
Chemicals contained in the non-formaldehyde electroless copper technology are regulated
by the Clean Water Act, the Safe Drinking Water Act, the Clean Air Act, the Superfund
Amendments and Reauthorization Act, the Emergency Planning and Community Right-to-Know
Act, and the Toxic Substances Control Act. The technology does not generate wastes listed as
hazardous (P or U waste) under RCRA, but some wastes may have RCRA hazardous
characteristics.
Social Benefits and Costs
A qualitative assessment of the private and external benefits and costs of this technology
suggests there would be net benefits to society if PWB manufacturers switched to the non-
formaldehyde electroless copper technology from the baseline. Among other factors, this is due
to lower occupational risks to workers and to reduced consumption of limited resources (water
and energy).
DRAFT
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7.3 TECHNOLOGY SUMMARY PROFILES
Figure 7.5 Production Costs and Resource Consumption of Non-Formaldehyde
Electroless Copper Technology
(Percent Change from Baseline with Actual Values in Parentheses)
-20
u
"o
%
m
s
&
-40
-60
-80
-100
(3.74 gal/ssf)
Production Costs
Energy Consumption
Non-Conveyorized
|H Water Consumption
7.3.6 Organic-Palladium Technology
Generic Process Steos and Tvoical Bath Sequence
Microetch
w.
^
Water Rinse 1 — ^
Pred
Water Rinse
Acid Dip
ip I
Conditioner
Equipment Configurations Evaluated: Non-conveyorized and conveyorized.
DRAFT
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7.3 TECHNOLOGY SUMMARY PROFILES
Risk Characterization
Table 7.23 summarizes human and environmental hazards and risk concerns for non-
proprietary chemicals in the organic-palladium technology. The risk characterization identified
no occupational or public health risk concerns for the pathways evaluated. However, proprietary
chemicals are not included hi this assessment and no toxicity data are available for some
chemicals.
Table 7.23 Summary of Human Health and Environmental Hazard Data and Risk
Concerns for the Organic-Palladium Technology
Chemical"
Hydrochloric Acid
Sodium Bisulfate
Sodium Carbonate
Sodium Bicarbonate
Sodium Hypophosphite
Sodium Persulfate
Trisodium Citrate 5,5-
Hydrate or Sodium Citrate
Human Health Hazard and Occupational
Bisks?1
Inhalation6
Toxicity0
(mg/m3)
0.007 (RfC)
ND
10 (NOAEL)
10 (NOAEL)"
ND
ND
ND
Risk
Concerns
NA
NA
NA
NA
NA
NA
NA
Dermal"1
Toxicity*
(mg/kg-d)
NDf
ND*
ND
ND
ND
ND8
ND
Risk
Concerns
NE
NE
NE
NE
NE
NE
NE
Carcinogenicity
Weight-of-
Evideoce
Classification
IARC Group 3
none
none
none
none
none
none
Aquatic
Toxicity
CC
<«tg/»)
0.1
0.058
2.4
2.4h
0.006
0.065
3.3
1 Only one organic-palladium technology was evaluated. All chemicals listed were present in that product line.
b Risk concerns are for MHC line operators (the most exposed individual).
c Inhalation risk concerns for non-conveyorized process only. Inhalation risk from fully enclosed, conveyorized
process is assumed to be negligible.
d Dermal risk concerns apply to both conveyorized and non-conveyorized equipment.
* Toxicity measure is RfC, RfD, NOAEL, or LOAEL as indicated. If not indicated, the type of toxicity measure was
not specified in the available information, but assumed to be a LOAEL in risk calculations.
r Chronic dermal toxicity data are not typically developed for strong acids.
8 Chemical has very low skin absorption (based on EPA's Structure-Activity Team evaluation); risk from dermal
exposure not expected to be of concern.
k Chemical properties and toxicity measures for sodium carbonate used in exposure assessment and risk
characterization since these compounds form the same ions in water and are used in aqueous baths.
ND: No Data. No toxicity measure available for this pathway.
NE: Not Evaluated, due to lack of toxicity measure.
NA: Not Applicable. Inhalation exposure level was not calculated because the chemical is not volatile (vapor
pressure below 1 x 10'3 torr) and is not used in any air-sparged bath.
Performance
For the purposes of the Performance Demonstration project, the organic-palladium and
tin-palladium technologies were grouped together into a single palladium technology category.
The performance of the palladium technology was demonstrated at ten test facilities. The
Performance Demonstration determined that this technology has the capability of achieving
comparable levels of performance to electroless copper.
DRAFT
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7.3 TECHNOLOGY SUMMARY PROFILES
Production Costs and Resource Consumption
Computer simulation was used to model key operating parameters, including the time
required to process a job consisting of 350,000 ssf and the amount of resources (water and
energy) consumed. This information was used with a hybrid cost model of traditional cost (i.e.,
capital costs, etc.) and activity-based costs to determine average manufacturing costs per ssf and
water and energy consumption per ssf. With either equipment configuration, the organic-
palladium technology consumed less water and energy and was more cost-effective than the
baseline process (non-conveyorized electroless copper). In addition, the conveyorized organic-
palladium process consumed less water than the non-conveyorized process ($1.13 gal/ssf vs.
$1.35 gal/ssf, respectively), but consumed more energy (148 Btu/ssf vs. 66.9 Btu/ssf). However,
the conveyorized organic-palladium is not as cost effective as the non-conveyorized process
($0.17/ssf vs. $0.15/ssf, respectively). Figure 7.6 lists the results of these analyses and illustrates
the percent changes in costs and resource consumption for either equipment configuration from
the baseline.
Figure 7.6 Production Costs and Resource Consumption of Organic-Palladium Technology
(Percent Change from Baseline with Actual Values in Parentheses)
(1.35 gal/ssf) (66.9 Btu/ssf)
-100
Conveyorized
Production Costs
Energy Consumption
Non-Conveyorized
Water Consumption
DRAFT
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7.3 TECHNOLOGY SUMMARY PROFILES
Regulatory Concerns
Chemicals contained in the organic-palladium technology are regulated by the Clean
Water Act, the Clean Air Act, and the Emergency Planning and Community Right-to-Know Act.
The technology does not generate wastes listed as hazardous (P or U waste) under RCRA, but
some wastes may have RCRA hazardous characteristics.
Social Benefits and Costs
A qualitative assessment of the private and external (e.g., social) benefits and costs of this
technology suggests there would be net benefits to society if PWB manufacturers switched to the
organic-palladium technology from the baseline. Among other factors, this is due to lower
occupational risks to workers and to reduced consumption of limited resources (water and
energy).
7.3.7 Tin-Palladium Technology
Generic Process Stes and Tical Bath Seuence
1 Cleaner/
[Conditioner
I
4^"j Catalyst
|
1
—>. Water Rinse x 21
—>• Water Rinse x 2
^- Microetch
^J Accelerator
H*
Water Rinse x 2 -1 — ^.
1— >- Water Rinse x 2 1 — ->.
L
Predip 1
"
Acid Dip 1
Equipment Configurations Evaluated: Non-conveyorized and conveyorized.
Risk Characterization
Table 7.24 summarizes human and environmental hazards and risk concerns for non-
proprietary chemicals in the tin-palladium technology. The risk characterization identified
occupational inhalation risk concerns for two chemicals and dermal risk concerns for five
chemicals. No public health risk concerns were identified for the pathways evaluated. However,
proprietary chemicals are not inlcuded in this assessment and no toxicity values are available for
some chemicals. At least two of these chemicals (potassium carbonate and sodium bisulfate)
have very low skin absorption, indicating risk from dermal exposure is not expected to be of
concern.
Performance
For the purposes of the Performance Demonstration project, the organic-palladium and
tin-palladium technologies were grouped together into a single palladium technology category.
The performance of the palladium technology was demonstrated at ten test facilities. The
Performance Demonstration determined that this technology has the capability of achieving
comparable levels of performance to electroless copper.
DRAFT
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7.3 TECHNOLOGY SUMMARY PROFILES
Table 7.24 Summary of Human Health and Environmental Hazard Data and Risk
Concerns for the Tin-Palladium Technology
Chemical"
1,3-Benzenediol
Copper (I) Chloride'
Copper Sulfate'
Dimethylaminoborane
Ethanolamine
Fluoroboric Acid
Hydrochloric Acidh
Hydrogen Peroxide
[sopropyl Alcohol;
or 2-Propanol
Lithium Hydroxide
Palladium'
Palladium Chloridei
Phosphoric Acid
Potassium Carbonate
Sodium Bisulfate
Sodium Chloride
Sodium Hydroxide
Sodium Persulfate
Stannous Chloride"1
Sulfuric Acidh
Triethanolamine
Vanillin
Human Health Hazard and Occupational Risks"
Inhalation0
Toxicity*
(mg/mj)
ND
0.6 (LOAEL)
ND
ND
12.7 (LOAEL)
ND
0.007 (RfC)
79
980 (NOAEL)
ND
ND
ND
ND
ND
ND
ND
2 (LOAEL)
ND
ND
0.066 (NOAEL)
ND
ND
Risk
Concerns
NA
no
NE
NA
yes
NE
NA
no
no
NA
NA
NA
NE
NA
NA
NA
NA
NE
NA
yes
NA
NE
Dermal"
Toxieity*
(mg/kg-d)
100 (NOAEL)
0.07 (LOAEL)
ND
ND
320 (NOAEL)
0.77
ND
630 (NOAEL)
100 (NOAEL)
ND
0.95 (LOAEL)
0.95 (LOAEL)
ND
NDk
NDk
ND
ND
ND
0.62 (RfD)
ND
32 (LOAEL)
64 (LOAEL)
Risk
Concerns
no
yes
NE
NE
no
yes
NE1
no
no
NE
yes
yes
ND
NE1
NE
NE1
NE
NE1
yes
NE1
no
no
Carcinogenicity
Weight-of
Evidence
Classification
IARC Group 3
EPA Class D
none
none
none
none
IARC Group 3
IARC Group 3
none
none
none
none
none
none
none
none
none
none
none
none
none
none
Aquatic
Toxicity
CC
(mgfl)
0.0025
0.0004
0.00002
0.0078
0.075
0.125
0.1
1.2
9.0
ND
0.00014
0.00014
0.138
>3.0
0.058
2.8
2.5
0.065
0.0009
2.0
0.18
0.057
" Chemicals in bold were in all tin-palladium technologies evaluated, unless otherwise noted.
b Risk concerns are for MHC line operators (the most exposed individual).
c Inhalation risk concerns for non-conveyorized process only. Inhalation risk from fully enclosed, conveyorized
process is assumed to be negligible.
° Dermal risk concerns apply to both conveyorized and non-conveyorized equipment.
e Toxicity measure is RfC, RfD, NOAEL, or LOAEL as indicated. If not indicated, the type of toxicity measure was
not specified in the available information, but assumed to be a LOAEL in risk calculations.
f Either copper (I) chloride or copper sulfate was listed on the MSDSs for four of five tin-palladium lines evaluated.
B Estimated by EPA's Structure-Activity Team.
h Hydrochloric and sulfuric acid were listed on the MSDSs for four of five tin-palladium lines evaluated.
' Chronic dermal toxicity data are not typically developed for strong acids.
j Palladium or palladium chloride was listed on the MSDSs for three of five tin-palladium lines evaluated. The MSDSs
for the two other lines did not list a source of palladium.
k Chemical has very low skin absorption (based on EPA's Structure-Activity Team evaluation); risk from dermal
exposure not expected to be of concern.
1 Dermal exposure level for line operator of conveyorized equipment was in top ten percent of dermal exposures for all
MHC chemicals.
m Stannous chloride was listed on the MSDSs for four of the five tin-palladium lines evaluated. The MSDSs for the
remaining tin-palladium product line did not list a source of tin.
ND: No Data. No toxicity measure available for this pathway.
NE: Not Evaluated, due to lack of toxicity measure.
NA: Not Applicable. Inhalation exposure level was not calculated because the chemical is not volatile (vapor pressure
below 1 x 10'3 torr) and is not used in any air-sparged bath.
DRAFT
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7.3 TECHNOLOGY SUMMARY PROFILES
Production Costs and Resource Consumption
Computer simulation was used to model key operating parameters, including the time
required to process a job consisting of 350,000 ssf and the amount of resources (water and energy)
consumed. This information was used with a hybrid cost model of traditional cost (i.e., capital
costs, etc.) and activity-based costs to determine average manufacturing costs per ssf and water and
energy consumption per ssf. With either equipment configuration, the tin-palladium technology
consumed less water and energy and was more cost-effective than the baseline process (non-
conveyorized electroless copper). In addition, the conveyorized tin-palladium process consumed
less water and energy and was more cost-effective than the non-conveyorized process ($0.12/ssf vs.
$0.14/ssf, respectively). Figure 7.7 lists the results of these analyses and illustrates the percent
changes in costs and resource consumption for either equipment configuration from the baseline.
Figure 7.7 Production Costs and Resource Consumption of Tin-Palladium Technology
(Percent Change from Baseline with Actual Values in Parentheses)
-100
Conveyorized
Production Costs
Energy Consumption
Non-Conveyorized
Water Consumption
Regulatory Concerns
Chemicals contained in the tin-palladium technology are regulated by the Clean Water Act,
the Safe Drinking Water Act, the Clean Air Act, the Superfund Amendments and Reauthorization
Act, the Emergency Planning and Community Right-to-Know Act, and the Toxic Substances
Control Act. In addition, the technology generates a waste listed as hazardous (U waste) under
RCRA.
DRAFT
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7.3 TECHNOLOGY SUMMARY PROFILES
Social Benefits and Costs
A qualitative assessment of the private and external (e.g., social) benefits and costs of this
technology suggests there would be net benefits to society if PWB manufacturers switched to the
tin-palladium technology from the baseline. However, this alternative contains chemicals of
concern for occupational inhalation risk (for non-conveyorized equipment configurations) and
occupational dermal contact risks (for either equipment configuration). Among other factors, net
social benefits would be due primarily to lower production costs and to reduced consumption of
limited resources (water and energy).
DRAFT
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REFERENCES
REFERENCES
HSDB. 1996. Hazardous Substances Data Bank. MEDLARS Online Information Retrieval
System, National Library of Medicine.
Keenan, Cheryl. 1997. Abt Associates, Inc. Personal communication with Lori Kincaid, UT
Center for Clean Products and Clean Technologies. April 7.
Mishan, E.J. 1976. Cost-Benefit Analysis. Praeger Publishers: New York.
Smith, Ted, Silicon Valley Toxics Coalition and Greg Karras, Communications for a Better
Environment. 1997. "Air Emissions of Dioxins in the Bay Area." March 27. As cited
in personal communication to Lori Kincaid, UT Center for Clean Products and Clean
Technologies. March 3.
U.S. Environmental Protection Agency (EPA). 1995. Printed Wiring Board Industry and Use
Cluster Profile. Design for the Environment Printed Wiring Board Project. September.
U.S. Environmental Protection Agency (EPA). 1996. The Medical Costs of Selected Illnesses
Related to Pollutant Exposure. Draft Report. Prepared for Nicolaas Bouwes, U.S.
EPA Regulatory Impacts Branch, Economics and Technology Division, Office of
Pollution Prevention and Toxics. Washington, DC. July.
U.S. Environmental Protection Agency (EPA). 1997. Implementing Cleaner Technologies in
the Printed Wiring Board Industry: Making Holes Conductive.
Unsworth, Robert E. and James E. Neumann. 1993. Industrial Economics, Inc. Memorandum
to Jim DeMocker, Office of Policy Analysis and Review. Review of Existing Value of
Morbidity Avoidance Estimates: Draft Valuation Document. September 30.
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