United States
Environmental Protection
Agency
Office of Pesticides
and Toxic Substances
EPA 560/4-88-004I
February 1988
4>EPA Title III Section 313
Release Reporting
Guidance
Estimating Chemical Releases From
Leather Tanning and Finishing
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I
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Estimating Chemical Releases From
Leather Tanning and Finishing
Facilities engaged in leather tanning and
finishing may be required to report annually
any releases to the environment of certain
chemicals regulated under Section 313, Title
III, of the Superfund Amendments and Re-
authorization Act (SARA) of 1986. If your
facility is classified under SIC codes 20
through 39 (leather tanning and finishing
plants generally fall under SIC code 3111)
and has 10 or more full-time employees, for
calendar year 1987 you must report all
environmental releases of any Section 313-
listed chemical or chemical category manu-
factured or processed by your facility in an
amount exceeding 75,000 pounds per year or
otherwise used in an amount exceeding
10,000 pounds per year. For calendar years
1988 and 1989 (and beyond), the threshold
reporting quantity for manufactured or pro-
cessed chemicals drops to 50,000 and 25,000
pounds per year, respectively.
This document has been developed to
assist those in the leather tanning and fin-
ishing industry in the completion of Part III
(Chemical Specific Information) of the Toxic
Chemical Release Inventory Reporting Form.
Included herein is general information on
toxic chemicals used and process wastes
generated, along with several examples to
demonstrate the types of data needed and
various methodologies available for esti-
mating releases. If your facility performs
other operations in addition to leather tan-
ning and finishing, you must also include any
releases of toxic chemicals from these
operations.
Step One
Determine if your facility processes or
uses any of the chemicals subject to
reporting under Section 313.
A suggested approach for determination
of the chemicals your facility uses that could
be subject to reporting requirements is to
make a detailed review of the chemicals and
materials you have purchased. If you do not
know the specific ingredients of a chemical
formulation, consult your suppliers for this
information. If they will not provide this in-
formation, you must follow the steps outlined
to handle this eventuality in the instructions
provided with the Toxic Chemical Release
Inventory Reporting Form.
The list presented here includes chemi-
cals typically used in leather tanning and
finishing that are subject to reporting under
Section 313. This list does not necessarily
include all of the chemicals your facility uses
that are subject to reporting, and it may
include many chemicals that you do not use.
You should also determine whether any of the
listed chemicals are created during process-
Ing at your facility.
Biocides: Paranitrophenol (PNP),
2-phenylphenol (ortho-phenylphenol)
Pickling compounds: Sulfuric acid
Tanning agents: Chromium compounds,
cresols, formaldehyde, phenol
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Dyes, pigments, and coloring agents:
Titanium dioxide, organo-metallic dyes/
pigments (barium, cadmium, chromium,
cobalt, copper, lead, nickel, and zinc
compounds), Acid Blue 9, Basic Green 4,
Direct Black 38, cyanide-containing
compounds
Miscellaneous solvents and chemicals:
Acetone, ammonia, ammonium sulfate,
chlorine, 1,2-dichlorobenzene, dichloro-
methane (methylene chloride), n-dioctyl
phthalate (bis-[2-ethylhexyl] phthalate),
ethyl benzene, glycol ethers, hexa-
chloroethane, hydrochloric acid, methyl
ethyl ketone, phosphoric acid, sodium
hydroxide, tetrachloroethylene (per-
chloroethylene), 1,1,1 -trichloroethane,
trichloroethylene, toluene, xylene
Step Two
Determine if your facility surpassed the
threshold quantities established for
^reporting of listed chemicals last year.^
You must submit a separate Toxic Chemi-
cal Release Inventory Reporting Form for
each listed chemical that is "manufactured,"
"processed," or "otherwise used" at your
facility in excess of the threshold quantities
presented earlier. Manufacture includes
materials produced in byproduct or impu-
rities. Toxic compounds that are incorpor-
ated into your products (for example, chro-
mium in tanning formulations) would be
considered "processed" because they become
part of the marketed finished product. De-
greasing solvents, cleaning agents, and other
chemicals that do not become part of the
finished product (for example, pickling agents
and dye carriers) would be considered
"otherwise used."
In leather tanning and finishing pro-
cesses, the release of toxic chemicals to the
environment usually results from the
"processing" or "use" of these chemicals
rather than their "manufacture." You must
keep in mind, however, the toxic chemicals
that may be "manufactured" indirectly during
the process. For example, ammonia is gen-
erated during the biological decay of proteins
in wastewater. Although ammonia is not a
desired "product" of the tannery, it is never-
theless "manufactured" during the process,
and if produced in sufficient quantities, it is
subject to reporting requirements.
The amount of a chemical processed or
otherwise used at your facility represents the
amount purchased during the year, adjusted
for beginning and ending inventories. To
ascertain the amount of chemical in a mixed
formulation, multiply the amount of the
mixture (in pounds) by the concentration of
the chemical (weight percent) to obtain the
amount of chemical processed.
Example: Determining whether
sulfuric acid was used in sufficient
quantity to require reporting under
Section 313.
A tanning facility used 95 percent pure
sulfuric acid in the pickling process (and
for other miscellaneous purposes). In
1987, 3,000 pounds of this material was
in storage at the beginning of the. year,
18,000 pounds was purchased, and
6,000 pounds was in storage at the end of
the year. The quantity ofH2SO4 used by
this facility equals:
(3,000 Ib x 0.95) (beginning
inventory) +
(18,000 Ib x 0.95) (purchased) -
(6,000 Ib x 0.95) (ending inventory) x
= 14,250 Ib
Because this amount exceeds the
threshold quantity of 10,000 pounds for a
chemical that is "otherwise used," the
plant in this example would have to submit
a Toxic Chemical Release Inventory
Reporting Form for H2SO4.
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A listed chemical may be a component of
several formulations you purchase, so you
may need to ask your supplier for informa-
tion on the concentration (percentage) of the
chemical in each. For chemical categories,
your reporting obligations are determined by
the total amounts of all chemicals in the
category. For example, cyanide-containing
compounds are found in sharpening agents,
tanning agents, dyes, and pigments. The
quantity of cyanide compounds used is the
sum of the quantities used in these areas.
For metal compounds, the amount of metal
compound is used to determine whether
threshold is exceeded, whereas the reported
release represents the amount of parent
metal only. For a substance such as lead
chromate, the amount used must be con-
sidered in determining whether the threshold
is met for both lead-containing and
chromium-containing compounds.
You must complete a report for each
chemical for which a threshold is exceeded.
The thresholds apply separately; therefore, if
you both process and use a chemical and
either threshold is exceeded, you must report
for both activities. If neither threshold is
exceeded, no report is needed.
Step Three
Identify points of release for the
chemical(s) subject to reporting.
An effective means of evaluating points of
release for listed toxic chemicals is to draw a
process flow diagram identifying the opera-
tions performed at your facility. The figure
provided here (oil pages 4 and 5) is an exam-
ple flow diagram of a leather tanning process
from beam house operations to finishing.
Because each facility is unique, you are
strongly urged to develop a flow diagram for
your particular operations that details the
input of materials and chemicals and the
waste sources resulting from the operation of
each unit.
Wastewater is generated by almost every
unit of operation in a leather tanning and
finishing facility. Solid wastes containing
toxic substances are generated from the
following sources:
Shavings
Buffing dust
Wastewater screenings
Wastewater treatment sludges
Some solid wastes are recycled into other
products, such as leatherboard. If recycling/
recovery is performed offsite, the amounts of
toxic chemicals contained in the solid waste
do not have to be reported; however, if these
solid wastes are to be disposed of offsite, or if
their fate is unknown, then they must be
reported as an offsite transfer. If recycling is
performed on site, the recycled wastes are not
considered to be "disposed of or "trans-
ferred"; they are simply considered an exten-
sion of the facility's processing operation.
Any toxic chemicals released during recycling
must be included in the facility's totals.
Buffing operations, coating operations in
the finishing of leather (spray booths, dryers),
and the degreasing of pigskin and sheepskin
are all likely to generate air emissions that
constitute toxic chemical releases. Typically,
control devices are in place to limit emissions
from these points, in which case, these
sources are considered "stack or point emis-
sions"; if not, they may be considered "fugi-
tive or nonpoint air emissions," depending on
the individual facility.
Your reporting must account for all
releases.
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RECEIVE AND
STORE HIDES
SIDE AND TRIM
. WEIGH AND SORT
WATER
DISINFECTANTS
NONIONIC SURFACTANTS
SODIUM SALTS
PROCESS PROCESS
WASTE- SOLID
WATER WASTE
SOAKING
DIRT, BLOOD,
SALT, PROTEINS,
CHEMICALS
FLESHING
WATER
DEPILATORY AGENTS
(CALCIUM HYDROXIDE,
SODIUM SULFIDE)
SHARPENING AGENTS
PROTEOLYTIC ENZYMES
NONIONIC SURFACTANTS
DELIMING CHEMICALS
AMMONIUM SULFATE
AMMONIUM CHLORIDE
SALT
ACID
H2SO4
WATER
TANNING AGENTS
CHROMIUM COMPOUNDS
ALUM
SYNTANS
GLUTERALDEHYDES
HEAVY OILS
FLESHINGS
FATS
UNHAIRING
(PULP OR SAVE)
HIGH pH,
PROTEINS,
SULFIDES,
OTHER CHEMICALS
TANYARD
1
BATE
NH3 AND
OTHER CHEMICALS
PICKLE
LOWpHH2S04
TAN
UNFIXED
TANNING AGENTS
WRING
SPLIT AND SHAVE
UNFIXED
TANNING AGENTS
(OR BYPRODUCT)
SHAVINGS
TO RETAN
Example Flow Diagram of Leather Tanning and Finishing
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RE-
WATER
TANNING AGENTS
CHROMIUM COMPOUNDS
ALUM
GLUTERALDEHYDE
HEAVY OILS
SODIUM BICARBONATE
H2S04
DYES AND PIGMENTS *
WATER
BIOCIDES _
FAT (OILS)
CHEMICAL EMULSIFIERS
FAN, COLORING, FAT LIQUOR PROCESS PROCESS
1 WASTE- SOLID
1 WATER WASTE
T I iMcivcn
RE1
\
BLEAC
AND CO
\
PAN
TANNING AGENTS
»ING
LORING
r
FAT LIQUORING
\
r'
SETTING OUT
DRYING
\
TO FINI
1
r
3HING
r
TRIMMING AND
CONDITIONING
STAKING AND
DRYMILLING
^""^ \
BUFFING
BUFFING DUST
'
CONTROL
UNIT
\AIR RELEAS
VOLATILE T
ORGANICS
FINIS
ANDCC
HING
JATING
AND PIGMENTS ^
OILS ^
VACUUM
DUST ,
PASTING
PLATE WASH
AIR
EMISSION
' CAPTURED
/
BUFFING
ES DUST
EXCESS
CHEMICALS
r
FINISHING
RESIDUES
\
WASTEWATER
TREATMENT
1
DIRE
DISCH
OR
PO1
\ *.
"\ ..,.. , fe
SCREENING
1
t ^
A *"
1
r SLUDGE
ECT SOI
ARGE WAJ
TO DISPC
T/V
.ID
3TE
)SAL
Example Flow Diagram of Leather Tanning and Finishing (continued)
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Step Four
Estimate releases of toxic chemicals.
After all of the toxic chemicals and waste
sources have been identified, you can esti-
mate the releases of the individual chemicals.
Section 313 requires that releases to air,
water, and land and transfers to offsite facili-
ties be reported for each toxic chemical
meeting the threshold reporting values. The
usual approach entails first estimating re-
leases from waste sources at your facility
(that is, wastewater, air release points, and
solid waste) and then, based on the disposal
method used, determining whether releases
from a particular waste source are to air,
water, land, or an offsite disposal facility.
In general, there are four types of release
estimation techniques:
Direct measurement
Mass balance
Engineering calculations
Emission factors
Descriptions of these techniques are provided
in the EPA general Section 313 guidance
document, Estimating Releases and Waste-
Treatment Efficiencies for the Toxic Chemical
Release Inventory Form.
Provisions of the Clean Air Act, Clean
Water Act, Resource Conservation and Re-
covery Act, and other regulations require
monitoring of certain waste streams. If
available, data gathered for these purposes
can be used to estimate releases. When only
a small amount of direct measurement data
is available, you must decide if another
estimation technique would give a more
accurate estimate. Mass balance techniques
and engineering assumptions and
calculations -can be used in a variety of
situations to estimate toxic releases. These
methods of estimation rely heavily on process
operating parameters; thus, the techniques
developed are very site-specific. Emission
factors are available for some industries in
publications referenced in the general Section
313 guidance document. Also, emission
factors for your particular facility can be
developed in-house by performing detailed
measurements of wastes at different pro-
duction levels.
If direct measurement data are not avail-
able, mass balances combined with engin-
eering calculations provide the next most
effective means of estimating releases at
leather tanning and finishing facilities. Be-
cause most of the chemicals are "processed"
or "otherwise used," the quantity of chemical
input to the facility equals the quantity of the
chemical leaving as product plus the quantity
leaving as waste (before treatment). The
quantity of chemical in the leather product
should be known by the manufacturer
(through engineering calculation of tanning
and dyeing chemical uptake rates). If the
chemical input quantity and the quantity
leaving in the product are known, the quan-
tity of chemical in the waste is also known.
This is especially effective for estimating toxic
metal releases, as they are not destroyed
during treatment; rather, they are transferred
from one medium to another. This method
cannot be applied as easily to organic toxics
because transformation during waste treat-
ment must be accounted for. In general, the
difficulty with this method is determining the
quantity of chemical released in different
media.
Toxic Releases Via Wastewater
Typically, wastewater is centrally collect-
ed, treated, and disposed of. For this reason,
the release estimation often can be made by
focusing on only one waste disposal stream.
6
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Most facilities dispose of their wastewater
to publicly owned treatment works (POTWs),
whereas others discharge their wastewater
directly to nearby bodies of water. Waste-
water treatment standards set forth by EPA
in 1983 require leather tanning and finishing
facilities to meet effluent limitations for
various wastewater parameters, including
total chromium. Except for small facilities
that dispose of their wastewater to POTWs,
each facility, whether discharging to a POTW
(under national pretreatment standards) or
directly to a body of water (under the National
Pollution Discharge Elimination System,
NPDES) must monitor its wastewater output
for total chromium. Some facilities are also
required by their pretreatment or NPDES
permits to monitor for other toxic chemicals,
such as toxic metals (lead, copper, cadmium,
nickel, and zinc) and ammonia. This moni-
toring information can be used directly in the
calculation of toxic releases via wastewater,
as shown in the following example.
Example: Using direct measurement
to estimate toxic release via waste-
water.
The NPDES permit of a leather tanning
facility requires daily monitoring of
waste water flow volume and biweekly
analysis of a daily composite sample of
this discharge for total chromium. The
amount of chromium in the wastewater
can be calculated as follows:
Pounds of chromium released in
wastewater per day =
gallons of wastewater/ day x
micrograms of chromium/ liter x
3. 78 liters/ gal x
1 lb/ 435,000,000 fj.g
The total chromium analytical results and
the calculated releases calculated by this
equation are presented below.
Discharge
flow rate. Total
million chromium, Releases,
gal/day ng/liter Ib/day
0.415 918 3.2
0.394 700 2.3
0.417 815 2.8
0.440 683 2.5
0.364 787 2.4
0.340 840 2.4
0.457 865 3.3
0.424 643 2.3
0.463 958 3.7
0.414 681 2.4
0.476 680 2.7
0.431 627 2.3
0.369 807 2.5
0.392 729 2.4
0.323 964 2.6
0.302 722 1.8
0.358 566 1.7
0.322 510 1.4
0.330 630 1.7
O.322 630 1.7
0.408 652 2.2
0.442 649 2.4
O.356 695 2.1
0.390 758 2.5
0.423 658 2.3
0.487 970 3.9
These data result in an average daily
release of 2.44 pounds. If the plant
discharges 250 days during the year, the
total amount of chromium released to
wastewater would thus be 6 10 pounds.
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For toxic chemicals not monitored in the
wastewater discharge, an alternative method
of estimating releases is needed. One such
method, discussed previously, is the use of a
mass balance combined with engineering
calculations. The following example shows
how this method can be used to estimate
releases of a toxic dye via wastewater.
Example: Using a mass balance and
engineering calculations to estimate
toxic release via wastewater:
In 1987, a tanning andjinishing
facility used a total of 89,000 pounds of
Direct Black 38 in its coloring and bleach-
ing process step. For the batches in which
this dye was used, the pH level in the
process drum was adjusted to 6.0. The
percentage uptake of the dye in the leather
ts afunction of a number of factors, in-
cluding pH and the type ofsyntans
present The relationship between these
factors can be found in standard refer-
ences on leather processing. Based on
such information, the facility operators
estimated that the uptake rate for Direct
Black 38 is 82 percent. This means 82
percent of the 89,000 pounds of Direct
Black. 38 was retained in the leather
product and the remaining 15,020 pounds
was drained to the wastewater collection
system.
In the collection system at this facility,
the dye flows through wastewater treat-
ment before it is discharged, where it is
btodegraded, volatilized to the air, or ad-
sorbed onto sludge particles, or it passes
through the process untreated. For dyes,
the latter two fates are the most common.
Data, on wastewater treatment effective-
ness are needed to finish the estimation of
Direct Black 38 releases to water (percent
passthrough) and to determine the quan-
tity retained in the wastewater treatment
sludge for ultimate disposal as solid waste
(percent partitioned to sludge). Waste-
water treatment effectiveness is very site-
and operation-specific; therefore, estimates
are not presented in this example.
It is suggested that any monitoring data
for the chemical in question in the influent,
effluent, and sludge of the treatment process
be used to determine the chemical's fate. An
elaborate set of monitoring data is not neces-
sary; just enough to provide a rough estimate
will do. Alternatively, you could look in the
literature for wastewater treatment fates in
systems similar to those at your facility that
treat wastewater with similar characteristics.
The EPA general Section 313 guidance docu-
ment contains a number of citations on
wastewater treatment effectiveness for some
of the chemicals subject to reporting.
If your facility uses a listed mineral acid
or base but this acid or base is effectively
neutralized in use or during wastewater
treatment (to pH of 6 to 9 as required by most
effluent standards), no release quantities
should be reported. If the acid or base is
transformed into a reportable substance,
however, you must estimate the quantity of
this substance manufactured to determine if
the threshold value has been reached. For
example, sulfuric acid neutralized by sodium
hydroxide yields sodiupi sulfate, which is a
listed chemical.
Toxic Releases Via Solid Waste
Most solid wastes from tanning and fin-
ishing facilities are specifically excluded from
hazardous waste regulations under RCRA.
Releases of toxic chemicals in these wastes
still must be estimated, however. The RCRA
regulations exclude certain solid wastes from
leather processing that contain chromium;
the exclusion does not apply, however, if
other materials are also present in the
chromium-containing waste at levels deemed
to be hazardous. Therefore, analytical moni-
toring of solid waste under RCRA generator
requirements is site-specific for tanneries. If
any solid wastes at your facility are subject to
RCRA reporting requirements, this informa-
tion can be used for direct estimating of toxic
releases.
8
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For solid wastes generated directly from
the shaving and buffing of hides, the concen-
tration of a toxic chemical in the solid waste
is roughly equal to the concentration in the
leather at that point in the process. Thus, if
the amount of toxic chemical in the leather
product and the quantity of shavings and
buffing dust generated are known, the
quantity of toxic chemical released in these
particular solid wastes can be estimated.
This estimating technique can be used in
conjunction with a mass balance to estimate
overall releases from the facility, as shown in
the following example.
Example: Using a mass balance and
engineering calculations to estimate
solid waste releases of chromium.
In 1987, a leather tanning and fin-
ishing facility used 750,000 pounds of 15
percent (as Cr2OJ basic chromic sulfate
solution in its tanning process. Waste-
water monitoring data on the facility's
effluent indicate that 3,600 pounds qfCr
was discharged during the year. The
750,000 pounds of chromic sutfate solution
used contained 77,000 pounds qfCr. In
the tanning process at this facility, the
overall chromium uptake rate in the leather
is estimated to be 80 percent. Therefore,
61,600 pounds qfCr was left in the leather
and 15,400 pounds was sent to
wastewater treatment.
Based on estimates by facility oper-
ators, the quantity of shavings and buffing
dust generated after tanning amounted to
approximately 5 percent of the leather
produced. Assuming that these solid
wastes have the same concentration qfCr
as the final product leather, they would
contain the 5 percent (or 3,080 pounds) of
the 61,600 pounds qfCr that remains fixed
in the tanning process.
The quantity ofCrin the sludge gen-
erated during wastewater treatment would
be the difference between the amount
discharged to wastewater treatment
(15,400 pounds) and the amount esti-
mated to be in the wastewater effluent
(3,600 pounds), or 11,800 pounds. The
total Cr released via solid waste would be
the sum of the sludge and shavings and
buffing dust, or 14,880 pounds. Using this
approach, the plant in this example could
report a total release of 15,000 pounds of
Cr via solid waste.
Emission factors can also be used in
estimating toxic releases via solid waste. The
EPA publication entitled "Assessment of
Industrial Hazardous Waste Practices, Leath-
er Tanning and Finishing Industry," contains
factors based on quantities of various solid
wastes generated by different types of facili-
ties. It also includes typical concentrations of
toxic metals found in these wastes. Emission
factors should only be used when other
methods of estimation cannot be applied,
however.
Toxic Releases to Air
Typically, air emissions from leather
tanning and finishing facilities will not have
been measured. Therefore, mass balances
and/or engineering calculations must be
used. If the quantity of a toxic chemical has
been directly measured in the solid waste and
wastewater from a facility, the quantity re-
leased to air can be estimated by determining
the difference between that amount and the
total quantity of that chemical used. Usually,
this much information will not be available
on those compounds released to air; thus,
engineering assumptions must be used.
Example: Using an engineering
assumption to estimate air releases of
1,1,1-trichloroethane (1,1,1-TCE).
The chemical 1,1,1-TCE is used in the
application of a coating in a leather-
finishing facility. The. coating is applied to
the leather with a roll coating machine.
The leather is then placed in a dryer,
where the 1,1,1 -TCE in the coating evap-
orates. It can be assumed that all of the
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1,1,1 -TCE is released to air. Assuming
50,000 pounds of this coating (containing
30 percent 1,1,1-TCE) is used in a year,
15,000 pounds of 1,1,1 -TCE would be
released to air. If the dryer vent is
equipped with a control device, any
transfer of 1,1,1 -TCE to solid or liquid
waste must be accounted for.
Other Toxic Releases
Leather tanning and finishing facilities
produce other wastes from which toxic
chemicals may be released. These include:
Residues from pollution control
devices
Wash water from equipment
cleaning
Product rejects
Used equipment
Empty chemical containers
Releases from these sources may already
have been accounted for, depending on the
release estimation methods used. These
items (and any other of a similar nature)
should be included in the development of
your process flow diagram.
The contribution of sources of wastes
such as cleaning out vessels or discarding
containers should be small compared with
process losses. If you do not have data on
such sources (or any monitoring data on
overall water releases), assume up to 1 per-
cent of vessel content may be lost during
each cleaning occurrence. For example, if
you discard (to landfill) "empty" drums that
have not been cleaned, calculate the release
as 1 percent of normal drum content. If the
drums are washed before disposal, this may
contribute 1 percent of the content to your
wastewater loading.
Step Five
Complete the Toxic Chemical Release
Inventory Reporting Form.
After estimating the quantity of each
chemical released via wastewater, solid
waste, and air emissions, you must deter-
mine the amount of each chemical released to
water, land, or air or transferred to an offsite
disposal facility. This determination will be
based on the disposal method you use for
each of your waste streams. Enter the re-
lease estimates for each chemical or chemical
category in Part III of the Toxic Chemical
Release Inventory Reporting Form. Also enter
the code for each treatment method used, the
weight percent by which the treatment re-
duces the chemical in the treated waste
stream, and the concentration of the chemi-
cal in the influent to treatment (see instruc-
tions). Report treatment methods that do not
affect the chemical by entering "0" for
removal efficiency.
10
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For More Information
Emergency Planning
and Community
Right-to-Know
Hotline
(800) 535-0202
or
(202) 479-2449
(in Washington, B.C.
and Alaska)
Small Business
Ombudsman
Hotline
(800) 368-5888
or
(703) 557-1938
(in Washington, D.C.
and Virginia)
The EPA brochure, Emergency Planning
and Community Right-to-Know Act, Section
313 Release Reporting Requirements (EPA
560/4-88-001) presents an overview of the
new law. It identifies the types of facilities
that come under the provisions of Section
313, the threshold chemical volumes that
trigger reporting requirements, and what
must be reported. It also contains a complete
listing of the chemicals and chemical cate-
gories subject to Section 313 reporting. The
EPA publication. Estimating Releases and
Waste-Treatment Efficiencies for the Toxic
Chemical Release Inventory Form (EPA 560/
4-88-002), presents more detailed informa-
tion on general release estimation techniques
than is included in this .document.
Additional Sources of Information
on Releases From Leather Tanning
and Finishing
U.S. Environmental Protection Agency. De-
velopment Document for Effluent Limitations
Guidelines New Source Performance Stan-
dards and Pretreatment Standards for the
Leather Tanning and Finishing Point Source
Category. Washington, D.C. November
1982.
U.S. Environmental Protection Agency. As-
sessment of Potential Toxic Releases From
Leather Industry Dyeing Operations. EPA-
600/2-78-215. Cincinnati, Ohio. October
1978.
U.S. Environmental Protection Agency. As-
sessment of Industrial Hazardous Waste
Practices, Leather Tanning and Finishing
Industry. NTIS PB-261018. November 1976.
Thorstensen, T.C. Practical Leather Tech-
nology. R.' E. Krieger Publishing Company,
New York. 1976.
11
"HI.S. Government Printing Office : 1988 - 516-002/80161
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