RESPONSE TO EXTERNAL COMMENTS
ON NEW CHEMICAL EXPOSURE LIMITS
IN TOXIC SUBSTANCES CONTROL ACT '5(e) ORDERS
MAY 19 95
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF POLLUTION PREVENTION AND TOXICS
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NEW CHEMICAL EXPOSURE LIMITS ("NCELs")
RESPONSE TO EXTERNAL COMMENTS
CONTENTS
I. Introductory Summary p.l
II. Inter-Agency Coordination p. 5
III. Establishment of the NCEL p. 10
IV. Analytical Method p. 15
V. Monitoring Requirements p. 27
VI. Respiratory Protection p. 32
VII. Recordkeeping p. 33
VIII. Miscellaneous p.35
IX. Non-NCELs p. 38
Attachment I - EPA's Method for Determining NCELs
Attachment II - List of References
Attachment III - August 1991 NCELs Provisions
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I. Introductory Summary
Section 5 of the Toxic Substances Control Act (TSCA) requires
submission of a premanufacture notice (PMN) to the U.S.
Environmental Protection Agency (EPA) at least 90-days before
commencing commercial manufacture of a new chemical substance.
Inhalation exposures of workers handling some of these PMN
substances may present an unreasonable risk of injury. To mitigate
such exposures and risks, EPA has developed "New Chemical Exposure
Limits" (NCELs) provisions in Orders issued under '5(e) of TSCA.
On August 6, 1991, EPA mailed to approximately 20 external
organizations draft NCELs provisions in a generic "boilerplate"
TSCA '5(e) Order, along with a cover letter soliciting comments.
(A copy of the 1991 draft is attached for reference in order to
help readers understand some of the comments.) Since then, EPA has
continued to make incremental revisions and to receive additional
input from various sources, generally during negotiations of
individual '5(e) Orders for specific chemicals. This "Response-to-
Comments" document provides the rationale for the corresponding
revised TSCA '5(e) Order NCELs provisions that were comprehensively
revised and, EPA believes, improved in response to those comments
from external organizations. These are standard provisions of
generic "boilerplate" '5(e) Orders that can, if warranted by the
facts, be modified in individual, chemical-specific '5(e) Orders.
This "Response-to-Comments" document presents (verbatim) the
comments received by EPA in 1991 and EPA's responses to those
comments. For each comment, an abbreviated name of the commenter
appears in parenthesis. In some places, similar comments are
grouped together and EPA's response appears after the last comment
in such a group. The following is a list of the organizations that
submitted comments and the abbreviations used herein to identify
them:
Occupational Safety and Health Administration ("OSHA")
National Institute for Safety & Health ("NIOSH")
Chemical Manufacturers Association ("CMA")
Synthetic Organic Chemical Manufacturers Association ("SOCMA")
Ecological and Toxicological Association of the Dyestuffs
Manufacturing Industry ("ETAD")
The Society of the Plastics Industry ("SPI")
Laborers' Health and Safety Fund of North America ("Labor")
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Amalgamated Clothing and Textile Workers Union ("ACTWU")
American Industrial Hygiene Association ("AIHA")
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The following is a brief summary of the comments and EPA's
responses:
A. Inter-Agency Jurisdiction & Coordination
Comment Summary: EPA should coordinate with other agencies
having expertise in worker protection. Where does EPA's
jurisdiction end and OSHA's begin?
Response Summary:
o EPA has ongoing communication with OSHA and NIOSH on worker
protection issues and has solicited input on the NCEls
program.
o EPA has sought to make its program consistent with OSHA's
wherever possible. EPA's NCELs provisions are modeled after
OSHA PELs and comprehensive standards, and now match OSHA's
program even more after NCELs revisions in response to public
comments.
o There will generally be no overlapping regulation of new
chemicals, because EPA's NCELs apply to new chemicals with
little or no data, so risk assessment is generally based on
analogue data from similar substances. EPA added an explicit
sunset provision to its '5(e) Orders which states that the
NCEL and respirator requirements are automatically nullified
if OSHA promulgates a PEL for the same substance. EPA may
raise NCELs cases to the attention of OSHA and NIOSH, in the
unlikely event that such is warranted by the toxicity data and
production volume associated with the new chemical substance.
B. Standard Setting
Comment Summary: EPA's method for setting NCELs concentrations
should not be based on such limited data, should parallel OSHA's,
should be published for comment, and should allow for prompt
modification in response to new data.
Response Summary:
o EPA is publicizing its method for setting NCELs
concentrations.
o On a case-by-case basis, EPA will consider setting NCELs
concentrations based on OSHA PELs and American Conference of
Government Industrial Hygienists (ACGIH) Threshold Limit
Values (TLVs), and will consider economic and technological
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feasibility, especially in cases where there is sufficient
evidence that the new chemical may present less risk than
existing substances which the new chemical may replace.
C. Analytical Method
Comment Summary: The NCELs analytical method criteria and
requirement for EPA approval are inconsistent with OSHA, overly
burdensome, and discourage adoption of the NCELs approach. EPA
should, like OSHA, set a performance-based standard for accuracy
of, for example, + 25% of the NCEL concentration with a confidence
level of 95%.
Response Summary:
o EPA replaced the requirement that EPA must approve the
company's analytical method with, instead, a requirement for
verification by an independent third-party laboratory.
o EPA adopted OSHA's performance standard of + 25% accuracy
with 95% confidence.
o Consistent with OSHA and NIOSH requirements, EPA raised the
lower quantitation limit from 0.1 times the NCEL to half the
NCEL, and reduced the minimum upper quantitation limit from
2,000 times the NCEL to twice the NCEL. However, the method
should cover the expected exposure range and, if a monitoring
sample exceeds the UQL by >10%, workers must wear 19C air-
supplied respirators.
o For analytical method verification and subsequent monitoring,
EPA will accept use of a laboratory accredited by the American
Industrial Hygiene Association (AIHA) as an alternative to
compliance with TSCA Good Laboratory Practice Standards
(GLPS). Other comparable programs may be used, if approved in
advance in writing by EPA.
o EPA clarified that certain analytical method requirements
apply only to method development/validation and not to
subsequent monitoring.
o EPA eliminated the cumbersome "Contents of Submission"
requirement that referenced the October 1987 OTS Guidance
Document for the Preparation of Quality Assurance Project
Plans.
D. Monitoring Requirements
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Comment Summary: The NCELs monitoring requirements are
unnecessarily more burdensome than OSHA's/not stringent enough.
Response Summary:
o EPA added an exemption from the monitoring requirements based
on documented and reliable objective data when exposures are
obviously so low that monitoring is unnecessary.
o For batch production processes of short durations, EPA reduced
the number of days between certain monitoring results required
to entitle a company to reduce respiratory protection or
terminate monitoring.
o EPA deleted the requirement for an annual report to determine
the need for additional monitoring after termination of
monitoring. OSHA does not require this. EPA is deleting only
the reporting requirement, not the monitoring requirement.
o EPA increased monitoring frequency from every 6 months to
every 3 months when samples measure above the NCEL.
E. Recordkeeping
Comment Summary: The NCELs recordkeeping requirements are
unnecessarily more/less burdensome than OSHA's.
Response Summary:
o EPA has attempted to keep recordkeeping requirements to the
minimum essential to maintain credible enforcement capability,
o Since existing OSHA regulations already require these employee
exposure records to be kept for 30 years, EPA is doing
likewise.
F. "Hierarchy of Controls"
Comment Summary: EPA should impose a mandatory "Hierarchy of
Controls" whereby respirator usage should be allowed only after
attainment of the NCEL via engineering controls and work practices
is determined unfeasible.
Response Summary:
o To allow flexibility for new chemicals manufactured in small
batches with few workers, EPA (unlike OSHA) will not mandate
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"Hierarchy of Controls"; however, EPA's '5(e) Orders expressly
state a preference for source reduction and engineering
controls over respirators.
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II. INTER-AGENCY COORDINATION
1. Comment (AIHA): AIHA suggests that one federal agency should
have regulatory jurisdiction and developmental authority for
workplace exposure limits. The NCEL proposal crosses
jurisdictional boundaries with OSHA and NIOSH in a way that could
be duplicative and counter-productive for the health and safety of
workers. Traditionally the agency with the power to establish
workplace exposure limits has been OSHA with scientific support
from NIOSH and other sources in the public and private sector.
AIHA suggests that confusion and inconsistency will result if
two agencies of the government regulate in the same area. Clear
authority should be given to one agency to avoid two sets of
standards for similar compounds resulting in a risk benefit debate
among affected parties. AIHA suggests adoption of one of the
following alternatives.
o EPA should defer to OSHA and NIOSH for NCEL standard
setting altogether.
o Alternatively, EPA should adopt OSHA criteria for
workplace exposure standard setting so that all factors
of cost, risk, feasibility, and toxicology are considered
in the arduous, but necessary, OSHA permissible exposure
limit process (AIHA makes this last suggestion on the
basis of the extensive experience of OSHA in standard
setting in an effort to maintain fair, consistent and
reasonable exposure limits with which all affected
parties can live.)
o Alternatively, EPA could rely on voluntary workplace
standard setting organizations such as the AIHA Workplace
Environmental Exposure Limits (WEEL) Committee and the
American Conference of Governmental Industrial Hygienists
(ACGIH) Threshold Limit Value (TLV) Committee for
assistance in the NCEL process.
The AIHA WEEL Committee and the ACGIH TLV Committee have
extensive experience with workplace exposure limit setting that
could lend third-party objectivity and assist in expediting the
process of setting exposure limits for new substances. AIHA would
be willing to discuss such a role for its WEEL Committee with EPA,
OSHA and NIOSH.
AIHA suggests that EPA and the Department of Labor (OSHA) and
Health and Human Services (NIOSH) work in total cooperation on all
aspects of this regulation relating to worker safety and health.
For clarity to EPA, OSHA, and private sector personnel who must
interpret and carry out this rule, AIHA suggests that once
cooperative agreement on provisions that extend beyond the 29 CFR
1910 worker protection rules is reached with OSHA these extra
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provisions should be (1) highlighted in italics or some other
fashion in the actual text of the rule and (2) placed in a table
for side by side comparison of TSCA Section 5(e) worker protection
requirements versus standard OSHA 29 CFR 1910 workplace
regulations.
2. Comment (CMA): EPA should coordinate with those agencies and
organizations that have been established to deal specifically with
occupational health and safety issues. Adding EPA to the
"universe" of organizations that sets permissible exposure limits
will lead to confusion and potential inconsistencies in the
workplace. EPA should take full advantage of the expertise of
other groups in developing occupational permissible exposure
limits. The following federal agencies and institutions are
charged with protecting the health of workers: the Occupational
Safety and Health Administration (OSHA), the National Institute for
Occupational Safety and Health (NIOSH), the American Conference of
Governmental Industrial Hygienists (ACGIH), the American Industrial
Hygiene Association (AIHA) and the American National Standards
Institute (ANSI). In embarking on this effort, the Agency should
strive to involve, or at least learn from, the agencies and
institutions, especially OSHA, which possess the required technical
expertise and experience necessary to either set a standard or
recommend guidelines. The historical experience of these groups
adds critical perspective to developing, administering and
enforcing NCELs.
EPA should consider certain questions before proceeding
further with the proposed NCELs program. What avenues of
communication must be established between EPA and other workplace-
directed agencies or institutions? Should an external consultant,
such as an appropriate OSHA representative, be enlisted to help
establish NCELs or, at the very least, to assist in formulating
procedures and policies to be used by EPA?
EPA should coordinate more closely with other Agencies that
have worker protection expertise. The Agency should take full
advantage of this expertise in developing occupational permissible
exposure limits and not set limits that will lead to confusion or
inconsistencies in the workplace.
3. Comment (SOCMA): SOCMA believes that EPA should limit the
scope of its NCELs program, and should defer to the longstanding
authority and expertise of OSHA on the establishment of workplace
exposure limits. Much of industry's concern would be alleviated if
EPA postponed implementation of the NCELs program until it develops
a mechanism to address adequately the following: (1) coordination
of EPA's efforts under the new chemicals program with the existing
efforts of OSHA with respect to the establishment of exposure
limits for chemicals, and (2) transfer of responsibility for
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workplace exposure from the NCELs program to OSHA at the earliest
appropriate time.
SOCMA certainly applauds EPA's goal to prevent potential
unreasonable risk to workers via inhalation exposure to chemical
substances subject to Section 5(e) Orders or SNURs. However, SOCMA
believes there is considerable risk that EPA's proposed approach --
involving the Agency's independent development of workplace
exposure limits -- will infringe on the longstanding jurisdiction
of OSHA over workplace safety and health conditions, and could
result in conflicting and burdensome requirements for industry.
Second, we are concerned that EPA's foray into the area of
setting workplace exposure limits will result in conflict between
EPA and the Occupational Safety and Health Administration ("OSHA")
concerning their respective jurisdictions over worker health and
safety, and could result in complex, conflicting and burdensome
requirements for industry.
The proposal also leaves unclear the effect that placement of
the new chemical on the TSCA Inventory would have on the
requirements of the NCELs program in the absence of OSHA
regulation. Does EPA intend that the requirements of the NCELs
program cease immediately (and automatically) upon termination of
a Section 5(e) Order or SNUR? Does EPA plan to coordinate its
NCELs effort with OSHA, in order to ensure that EPA and OSHA do not
establish conflicting requirements pertaining to hazard
communication, recordkeeping and reporting of workplace exposure
information?
4. Comment (CMA): Finally, EPA should clarify the extent to which
it will relinquish authority for regulating workplace exposure to
new chemicals after the completion of PMN review. At what point
does a chemical and its associated NCEL come under OSHA's authority
(that allows the establishment of a new permissible exposure
limit) ? This problem must be addressed by EPA and OSHA in a
cooperative effort, and reinforces the need for OSHA's involvement
in the process of establishing NCELs.
5. Comment (SPI): It is unclear from the draft when EPA's NCELs
end or when OSHA begins to assume regulation responsibilities.
This program covers new chemicals which at some date become
existing/old chemicals. It would appear that the enforcement
responsibility on regulatory authority should pass to OSHA at some
date. It is not clear from the proposal when this may occur.
If EPA believes that the chemical in question is a health
hazard, then the Agency should make the appropriate report to OSHA
under Section 9 of TSCA so as to avoid unnecessary duplication of
regulations. Any substance which is subject to the requirements of
an OSHA standard would presumptively not be an unreasonable risk
with respect to communication of hazards because OSHA's rule is
expressly intended to eliminate such risks. EPA could simply make
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the statement that the substance should be considered a health
hazard for purposes of the OSHA standard and that manufacturers
should prepare Material Safety Data Sheets and labels accordingly.
6. Comment (SOCMA): EPA's general proviso that it "could revoke
or modify the NCEL" in the event of OSHA regulation of workplace
exposure leaves a number of significant questions unanswered, and
leaves industry threatened with potentially conflicting OSHA and
EPA requirements. For example, the NCELs program is intended to
apply only to new chemicals that are not otherwise regulated by EPA
or other federal agencies. Therefore, by its terms there are no
circumstances that would support EPA's proposal that it "modify" an
NCEL in the face of OSHA regulation; in such an instance, EPA
should withdraw the NCEL. In fact, any Section 5(e) Order or SNUR
containing an NCEL should include a "sunset" provision that would
automatically terminate the NCEL in the event of OSHA (or other
federal agency) regulation.
7. Comment (ETAD): Further, NCELs should be accompanied by sunset
provisions that would be triggered automatically, for example, when
an exposure limit is established by OSHA. Such procedures, if
properly established, could ensure that any NCELs reflect the most
up-to-date scientific information available, with minimum burden on
EPA's and industry's resources.
8. Comment (ACTWU): These differences create potential conflicts
between EPA and OSHA when regulating very similar circumstances.
I think it is imperative that EPA tailor its NCEL activities to
complement those of OSHA rather than to act as if the NCEL is the
"only game in town". Otherwise employers, unions and workers will
be confronted with a difficult, and sometimes impossible, choice
between which rule to follow.
I believe that there is a relatively simple way to prevent
these conflicts and assure that coordinated efforts between the two
agencies maximize the efforts of all parties to protect workers.
EPA should continue to use its authority under the TSCAct to refer
to OSHA issues of hazardous exposures where the data justify it.
In addition, where the data are lacking to justify regulation at
the time, EPA should assure that sufficient data are gathered as
soon as possible to allow either agency to adopt whichever
regulations offer the most protection.
OSHA Reform
Finally, many of these issues are dealt with in the
Comprehensive Occupational Safety and Health Reform Act which is
now pending before the Congress. I strongly urge EPA to review
this legislation in detail, including the provisions for standard
setting (Title IV). This title offers an explicit role for EPA in
OSHA's standard-setting process, as well as many other improvement
relevant to the NCEL process. This legislation has a "reasonable"
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chance of passage (to borrow a phrase) and your efforts should take
this into account. Indeed, I think it is incumbent upon the Office
of Toxic Substances to inform the Congress of the potential
benefits offered by this legislation in resolving the problems to
which the TSCAct is addressed.
EPA Response: In general, EPA's NCELs fill a unique niche not
occupied by OSHA's PELs. By statute, the factors which must be
considered by EPA and the burden of proof applicable to NCELs under
'5 of TSCA are different from those applicable to OSHA PELs under
'6 of the OSH Act. When enacting TSCA in 197 6, Congress designed
'5 to regulate risks from new chemicals before they enter commerce.
TSCA '5 requires manufacturers of new chemicals to submit a pre-
manufacture notice (PMN) to EPA at least 90-days before commencing
manufacture for commercial purposes. Under '5(e) of TSCA, if EPA
finds that "information available to [EPA] is insufficient to
permit a reasoned evaluation of the health and environmental
effects of a chemical substance" and the substance "may present an
unreasonable risk of injury to health or the environment," EPA may
issue an Order to "prohibit or limit" activities associated with
the substance. However, TSCA does not require manufacturers of new
chemicals to develop any toxicity test data for submission with the
PMN. Therefore, to assess the risk from a new chemical, EPA often
must rely on toxicity data on existing chemicals with molecular
structures similar to the new chemical. EPA can use this same
analogue data to set NCELs concentrations when there is a defined
health endpoint and EPA believes the new chemical is not
significantly more toxic than its analogue.
Because EPA's NCELs apply to uncommercialized new chemicals
with little or no data, EPA and OSHA will generally not
simultaneously regulate the same substance. EPA may refer to OSHA
former new chemical substances subject to a NCEL, if additional
data is received regarding toxicity and exposure such as to
increase evidence of risk. Most likely, OSHA will not regulate a
PMN substance unless and until (1) the new chemical becomes more
widely commercialized with increased human exposures and (2)
toxicity data on the chemical is developed showing adverse health
effects. If so, OSHA could consider the new data in deciding
whether to adopt EPA's NCEL or set a different exposure limit. EPA
has added an explicit sunset provision to its '5(e) Orders which
states that the NCEL and respirator requirements are automatically
nullified if OSHA promulgates a PEL for the same substance.
Thus, there are a few areas where differences between EPA's
New Chemicals Program under section 5 of TSCA and OSHA's PEL
program under the Occupational Safety and Health Act necessitate
different treatments and different regulatory requirements. For
example, there usually is no established analytical method for
measurement of the new chemical substance. Thus, EPA imposes more
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detailed requirements for accuracy and precision, and requires
verification of the company's method. Also, EPA does not impose a
mandatory "Hierarchy of Controls." To allow flexibility for new
chemicals manufactured in small batches with few workers, the
company may elect, as an alternative to the NCELs provisions, to
use respirators specified by EPA based on exposure estimates
without actual monitoring data. However, EPA's '5(e) Orders
expressly state a preference for source reduction and engineering
controls over respirators.
EPA recognizes both the long-standing expertise of OSHA and
NIOSH in the area of worker protection, and the wide-spread
applicability of existing OSHA regulations to the workplace.
Therefore, EPA has made every effort to copy OSHA's exposure limits
provisions wherever appropriate. Consequently, in general, EPA
considers the body of law and guidance documents on OSHA's PELs as
relevant to resolving questions on interpretation of EPA's NCELs
provisions.
The various federal agencies involved with regulating
workplace safety do communicate and coordinate regularly. EPA
meets monthly with OSHA and NIOSH through the ONE (OSHA/NIOSH/EPA)
Committee to coordinate on various subjects of mutual interest.
EPA has solicited comments specifically on NCELs from OSHA and
NIOSH (including the August 1991 NCELs draft) and agency
representatives have met on several occasions specifically to
discuss EPA's NCELs. As reflected herein, OSHA and NIOSH have
submitted some written comments on NCELs, generally relatively
minor or technical in nature. OSHA and NIOSH have both
acknowledged the critical role of EPA's NCELs program in setting
exposure limits for new chemicals with limited data (See, e.g.
"Understanding EPA's New Chemical Exposure Limits Program," The
Synergist, American Industrial Hygiene Association, Fairfax,
Virginia, April 1995, p.6).
Lastly, given both the short 90-day statutory review period
and the obligation to protect confidential business information
(CBI) imposed on EPA, it would be inappropriate and impractical for
EPA to involve private organizations such as the ACGIH TLV
Committee and the AIHA WEEL Committee in setting NCEL
concentrations in individual chemical specific cases. Not only
would this add severe delay to the PMN process and appear to
abdicate governmental responsibility, but associated problems would
be raised concerning protection of TSCA CBI, particularly since
many members of these committees are employees of competing private
chemical manufacturing companies.
III. ESTABLISHMENT OF THE NCEL
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1. Comment (SOCMA): One of the major concerns of SOCMA members is
EPA's intention to establish NCELs for new chemical substances for
which no or little analytical data exist pertaining to the
potential risk associated with workplace exposure. Currently, the
setting of exposure limits by federal agencies (such as OSHA) is a
deliberative, thorough process, based on data and evidence of risk.
EPA's proposal to establish numerical exposure limits in the
absence of adequate data would undermine the credibility and value
of the standard-setting process and would result in the
establishment of limits that are without scientific foundation and
are therefore by definition arbitrary.
2. Comment (ETAD): First, ETAD believes that establishing
numerical exposure limits based on little or no relevant
information would be detrimental. The process by which OSHA sets
exposure limits is a thorough and deliberative process based on
detailed risk information. Attempting to set exposure limits in
the absence of such information would be arbitrary and could
undermine the credibility of other standard-setting activities.
EPA Response: EPA is required by TSCA to review PMNs and to
prevent unreasonable risks which may result from those To mitigate
potential unreasonable risks from operations involving new
chemicals, EPA may issue TSCA '5(e) Orders that set controls on
those operations. Such controls may take the form of required
respirator use or inhalation exposure limits. EPA is establishing
NCELs in recognition of a general consensus among industry, labor,
the scientific community, and government agencies that using
engineering controls and monitoring to meet inhalation exposure
limits is generally preferable to using respirators to mitigate
risks from inhalation exposures to toxic chemicals.
EPA's method of setting NCEL concentrations is consistent with
EPA's past and current methods of assessing the potential risks of
new chemical substances. Most PMNs provide little or no data
toxicity data on the PMN substance itself. Therefore, from the
inception of its New Chemicals program, EPA has often relied on
toxicity data on other chemicals with molecular structures similar
to the PMN substance to develop a Structure Activity Analysis
(SAR). Under this approach, EPA first identifies and reviews the
test data available for analogues and/or chemicals predicted to be
key metabolites of the new chemical substance. Then EPA uses SAR
to apply the results of the review to the new chemical substance.
EPA has used this procedure to establish current NCEL
concentrations. The current NCEL provisions clearly state that
these NCEL concentrations are "interim levels determined by EPA
based on the limited information available to the Agency at the
time of development of the Order." Nevertheless, EPA does perform
a careful review of all available data, including analogue data, to
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select an appropriate NCEL level. If adequate data to determine a
NCEL concentration for a particular chemical are not available, EPA
will not establish a NCEL for that substance.
As the preceding discussion makes clear, NCEL concentrations
based on relatively complete data are likely to reflect the high
quality of that data. In contrast, when PMN submitters do not
submit data adequate to address unreasonable risk issues within the
90-day review period, NCELs for those substances may be based on
limited information. EPA encourages companies to include relevant
data -- such as chronic or subchronic toxicity studies on close
analogues -- in their PMN submissions. (As discussed below,
companies should also provide information on relative risk and
feasibility.) With this data, EPA and the PMN submitter will be
better able to establish in the initial Consent Order a NCEL more
closely tailored to the actual risk presented by the PMN substance.
Alternatively, if additional data become available after
establishment of the NCEL, the regulated company may petition EPA
to change the NCEL in accordance with the Modification section of
the '5(e) Order.
3. Comment (CMA) : We also believe that the exposure limits EPA
intends to develop will be overly protective, be more restrictive
than OSHA's standards for analogous existing substances, discourage
companies from exercising the NCELs option, and result in continued
reliance on respirators to control new chemicals of concern.
EPA's procedures for developing and implementing NCELs must be
streamlined if the positive objectives of the NCELs concept are to
be realized.
4. Comment (CMA): EPA's framework for establishing NCELs should
parallel OSHA's process for setting PELs to the greatest extent
possible. In most instances, the driving force for a consent order
under Section 5(e) will be structural similarities between the new
substance and an analogous existing chemical. Since the new
substance will be regulated because it may have the same health
concerns as the analog, the workplace exposure limits for the two
chemicals should be identical. When an OSHA PEL exists for the
analog, it should be the basis for the NCEL.
If no PEL exists for the analog, EPA should base the NCEL on
the Threshold Limit Value (TLV) set by ACGIH. In the absence of a
PEL or TLV, or if the PMN chemical would fall under the OSHA dust
standard or another generalized OSHA standard, the NCEL should be
derived using established OSHA scientific criteria and methodology
for determining "significant risks."
EPA Response: For reasons explained elsewhere and highlighted in
the Introductory Summary outlined above, EPA believes that the new
NCELs provisions have been streamlined and improved in response to
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the external comments received. EPA does indeed wish to promote
the NCELs approach and hopes that the new provisions will be
utilized by industry.
Whenever there is a PEL or TLV for an analogue chemical
substance, EPA will review the underlying basis for that number.
EPA may conclude that the PEL or TLV is sufficiently protective.
However, EPA may also have additional data on the new chemical
substance as well as other similar analogues, and when accounting
for feasibility in risk management decisions, may determine that
adherence to the PEL or TLV may result in an inadequate level of
worker protection for the new chemical substance. By statute, the
factors which must be considered and the burden of proof applicable
to EPA's NCELs under '5 of TSCA are different than those applicable
to OSHA PELs under '6 of the OSHA Act, particularly with regard to
issues bearing on feasibility. (See EPA's next Response to Comment
regarding feasibility).
5. Comment (CMA): EPA's NCELs determinations should also consider
feasibility. Under the Occupational Safety and Health Act, OSHA
cannot set an exposure limit that is technologically or
economically infeasible. EPA should also establish exposure limits
that are within the bounds of feasibility. During consent order
negotiations, EPA should consider feasibility data provided by the
PMN submitter for its own and its customers' operations.
Subsequently, when a Significant New Use Rule (SNUR) is developed
for the Section 5(e) substance, EPA should consider the feasibility
concerns of other manufacturers and processors. The TSCA new
chemicals program should not impede innovation of new products.
EPA Response: As a matter of law, the congressional mandate
reflected in TSCA '5 gives EPA broad authority to establish
restrictions on new chemicals based on a finding of potential
unreasonable risk provided there is no significant loss of benefits
to society from issuing the Consent Order. As a matter of policy,
EPA will consider feasibility arguments (such as how the
concentration that EPA establishes as the NCEL should be influenced
by the company's technological capability to attain and detect that
level) on a case-by-case basis. In such cases, EPA encourages the
submission of data to support feasibility concerns.
Technological and economic feasibility of meeting an exposure
limit will be a key consideration in "safer substitute/relative
risk" cases where the company provides EPA with sufficient evidence
that a new chemical substance is a desirable replacement for a more
hazardous existing chemical. For such cases, EPA will strive to
set a NCEL for the new chemical at a level that not only protects
human health but also is feasible for the manufacturer. The Agency
is very interested in working with industry to achieve net risk
reduction.
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6. Comment (CMA) : In its August 6, 1991, letter to CMA, EPA
maintains that "[t]he NCELs provisions are modeled after the
permissible exposure limits (PELs) promulgated by the OSHA at 29
C.F.R. Part 1910 pursuant to Sections 6(a) and 6(b) of the
Occupational Safety and Health Act." Nonetheless, EPA's
description of the proposed NCELs program contains no information
concerning the methodology EPA intends to use to set exposure
limits. The Agency should provide detailed information concerning
the methodology it intends to use for setting exposure limits.
7. Comment (SOCMA): Our concern over EPA's proposal to establish
workplace exposure limits is intensified by the fact that EPA has
provided no suggestion in the draft Order as to how it plans to
develop NCELs, even in the unusual circumstance where adequate data
on risk are available for the chemical substance. Despite a brief,
informal statement that "the NCELs provisions are modeled after the
permissible exposure limits (PELs) promulgated by [OSHA]," the text
of the generic '5(e) Order itself, specifically Part C (see draft
Order at 22), contains no details of the methodology EPA plans to
use to establish NCELs.
8. Comment (ETAD): Prior to instituting its proposed program, EPA
should establish and publish for comment its methodology for
establishing NCELs. Such methodology should include: (1)
identification of the data to be considered in establishing NCELs;
(2) procedures for derivation of NCELs; (3) guidelines for a
determination that data are inadequate to support issuance of an
NCEL; (4) procedures for modifying NCELs based on development of
additional data; and (5) mechanisms for affected parties to provide
input to the process and to petition for modification of NCELs.
9. Comment (Labor): EPA will establish the new chemical exposure
limits as TWA's and STEL's [C(1) and (2)]. This approach places a
substantial burden on EPA with regard to worker protection,
particularly in view of the limited data available on most new
chemicals. The EPA methodology for establishing such limits
should, therefore, be written, peer reviewed, and made available to
anyone who requests it.
EPA Response: EPA's methodology for setting NCELs concentrations
is attached as Attachment I.
10. Comment (SOCMA): It is unclear from the draft section 5(e)
Order whether EPA will consider data on chemicals similar to the
new chemical substance (e.g., analogues) for purposes of
establishing NCELs, or whether the Agency intends to require
testing of the individual chemical substances.
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EPA Response: EPA generally regulates new chemical substances
based on analogue data without data on the PMN substance itself,
and NCELs will be handled likewise. Please refer to EPA's earlier
response addressing standard setting.
11. Comment: EPA also should create procedures for modifying
NCELs based on development of additional data, and should provide
affected parties with a specific mechanism to provide this data
voluntarily and to petition the Agency for a prompt modification of
NCELs. This would ensure that any NCELs established reflect the
most up-to-date scientific information available, with the minimum
burden possible placed on EPA's administrative resources. Such
methodology and procedures should be developed and incorporated
into EPA's draft proposal.
12. Comment (SPI): EPA says if more data becomes available, the
Agency could revoke or modify the NCEL. There should be a
procedure for this review including a time limit and "hammer"
provisions if EPA fails to act (p. 3 cover letter).
13. Comment (CMA): A mechanism is needed to assure that, when new
test data are available on Section 5(e) chemicals, the applicable
NCEL will be promptly modified or eliminated. An increasing number
of Section 5(e) Orders include testing requirements designed to
develop data on the end-points identified by EPA on the basis of
structural similarities. Often, the resulting data will show that
the new chemical is less toxic than the EPA-identified analog. In
these instances, prompt reconsideration of the NCEL will avoid
overly protective and stressful employee workplace controls.
EPA Response: All TSCA '5(e) Orders contain a "Modification and
Revocation" section with provisions authorizing such modifications
or revocations based on new information. EPA will consider test
data received on the new chemical substance and other information
bearing on the risk associated with the substance, and will modify
or revoke the NCEL if the data evaluation changes EPA's
determination of potential unreasonable risk. Such modifications
or revocations will be drafted in accordance with the New Chemical
Program's (NCP's) general policy which evaluates cases and requests
in the order in which they are received. The NCP is engaged in an
ongoing process to streamline its new chemical review to expedite
such decisions.
14. Comment (CMA): In developing a methodology for NCELs, EPA
should also clarify the conditions under which a Short Term
Exposure Limit (STEL) will be established. For many new chemicals,
STELs will be unwarranted. Where the driving force of a Section
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5(e) order is chronic health concerns based on structural
similarities, these concerns will be best addressed by a PEL.
STELs should be limited to situations where the new substance is
known or suspected to present an acute health hazard or where
short-term peak exposures are known or suspected to contribute to
the risk of chronic health effects. ACGIH has backed away from
setting STELs except in these situations. EPA should be consistent
in its new chemicals program.
EPA Response: Most NCELs will be based on chronic endpoints, and
consequently the average exposure over time is more important than
acute exposure. EPA concurs with CMA's comments regarding STELs.
EPA anticipates establishing STELs only in cases where there is a
potential acute health hazard, or, in CMA's words, "where short-
term peak exposures are known or suspected to contribute to the
risk of chronic health effects." In other cases, the STEL
provisions will be deleted from the section 5(e) Order. To date,
EPA has not issued a '5(e) Order containing a STEL.
IV. ANALYTICAL METHOD
A. Method Approval by EPA
1. Comment (SPI) : EPA should not require companies to submit
analytical methods to EPA for approval. The approach suggested by
OSHA in its health standards, that the method be demonstrably
accurate and precise within specified limits is more appropriate
because it is a performance standard rather than a specification
standard. So long as accuracy and precision are maintained, the
means by which the results are achieved are of no consequence to
the regulator. The current NCEL approach is reflective of a bias
in EPA for standard methods. Currently, OSHA rules specify +/- 25%
precision and a 95% confidence level and that the accuracy of the
method be documented. See for example, the benzene standard,
29 CFR 1910.1001(d) (6) .
2. Comment (CMA) : The extensive and extremely detailed sampling,
analytical and monitoring requirements of the NCELs program are too
burdensome. As a result, very few companies, particularly small to
mid-size ones, will choose to exercise the NCELs option as
currently written. The requirements should be streamlined and
mandate a performance-oriented approach that parallels comparable
OSHA standards.
3. Comment (CMA) : Before a NCEL can be implemented, EPA's draft
consent order would require Agency review and approval of the
analytical methods developed by the PMN submitter. This
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requirement will greatly add to the workload of industry and EPA
analytical chemists. It is estimated that as many as 200 person-
hours over a period of 180 days are necessary for method
development, validation and submittal. The introduction of
engineering controls in lieu of respirators could also be delayed
for a considerable period if EPA does not complete its review
promptly. Should the Agency acquire additional information about
a proposed analytical method or should the internal EPA review
process become protracted, PMN submitters and their customers may
have no choice but to implement respirator programs and to abandon
plans to install engineering controls if initial monitoring shows
they are necessary.
OSHA standards do not mandate Agency approval of analytical
methods. Rather, they simply establish minimum requirements for
the reliability/reproducibility of such methods. As a result,
employers have the latitude to develop and validate methods of
their own, meeting the general OSHA criteria. NIOSH already has
established analytical methods, while AIHA has accredited
laboratories to perform the analyses. Incorporation of this
approach into the NCELs program would provide similar flexibility
and performance orientation to companies subject to Section 5(e)
Orders.
4. Comment (CMA): Further flexibility could be achieved by
allowing PMN submitters to adopt established analytical methods
developed by NIOSH or other recognized sources for analogous
existing chemicals where the methods can be expected to be used
reliably for the new substances. In such situations, the submitter
should be relieved from the requirement of developing a new
analytical method when the submitter can document that an existing
method is known to provide valid data for the new substance. Given
the substantial effort required to develop new analytical methods,
the absence of this option could create major disincentives to
participate in the NCELs process.
5. Comment (CMA): Does EPA intend to review sampling strategies
before companies begin data collection? CMA recommends that
general analytical laboratory and sampling plans be acceptable to
avoid unnecessary delays and costs. Our member company analytical
chemists express considerable concern about EPA's specification for
newly developed industrial hygiene sampling and analytical methods.
EPA's specification requires that a method be usable across a
range of 2 x 104. Typical laboratory requirements, however,
dictate a range of 1 x 102. Specification for sampling and
analytical requirements should state the accuracy and precision
required rather than reliance on "approved" methods.
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EPA Response: EPA is no longer requiring agency review and
approval of the company's sampling and analytical method. Instead,
the company must submit its method to an independent third-party
laboratory for verification of the company's method validation
data. EPA believes this is necessary to ensure that there is an
adequate analytical method with which to accurately measure
workplace concentrations of a new chemical substance. EPA has also
revised the NCELs provisions to allow use of an AIHA accredited lab
as an alternative to compliance with TSCA GLPS, and to clarify that
many of the analytical method requirements in the NCELs provisions
apply only to method development/validation but not to subsequent
monitoring. This more performance-based approach has been
developed based on the NIOSH and OSHA method development criteria
currently applicable to the chemical industry (see Attachment II -
List of References). Similarly, EPA does not review sampling
strategies, but rather has established monitoring requirements
modeled closely after OSHA requirements. EPA expects that the
NCELs revisions minimizing inconsistencies with OSHA requirements
will make NCELs more feasible for companies to use.
B. Method Quantitation Range
1. Comment (NIOSH): NCEL quantitation limit (NQL) (page 16): The
NCEL definition of "quantitation limit" proposes a new term
different than the usual analytical definition of "limit of
quantitation" (LOQ) used by the American Chemical Society (ACS) and
NIOSH chemists. To avoid confusion with existing usage, a term
other than "quantitation limit" should be specified. It appears
that what is really being specified by EPA are precision and
accuracy requirements covering a range of 0.1 to 2,000
time the NCEL. Is it necessary to specify precision and accuracy
up to 2,000 times the NCEL? What happens if the method cannot meet
this requirements?
2. Comment (OSHA): Since the type of respiratory protection
required is based on concentration thresholds greatly above the
NCEL, I understand the reason for the requirement in section
B.(4)(i) that the analytical method be capable of quantifying the
new PMN substances from the NQL through 2,000 times the NCEL. The
ability to measure concentrations over such a wide range may be
restricted in many cases by limited flexibility in the sampling
procedure.
3. Comment (CMA): An NQL of 2 or 3 levels below the NCEL should
be sufficient, especially if the detection limit signal to noise
ratio is set at five to one. If the NCEL is set at a ppb level, it
will be impossible to reach an order of magnitude below the NCEL,
particularly for short-term samples.
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4. Comment (SPI): Page 16 (4)(i) - EPA should define and provide
justification for "one order of magnitude."
5. Comment (SPI): Page 16 - It is unclear why the difference of
the NQL and the NCEL doesn't vary with the magnitude of the NCEL.
EPA Response: EPA's original requirement for the method to be
capable of quantifying the PMN substance up to 2,000 times the NCEL
was included to ensure the analytical method would be reliable at
higher concentrations where 19-C air-supplied respiratory
protection (with a NIOSH Assigned Protection Factor (APF) of 2,000)
may be necessitated by the monitoring results. For lower
concentrations, EPA based the frequency of monitoring upon the
action level (AL = 0.5 NCEL). Thus, the method must be reliable
below the action level. One order of magnitude below the NCEL was
considered reasonable to ensure a practical yet smaller range
around the AL.
EPA has changed the NCELs provisions to state that the
analytical method should be able to reliably quantify
concentrations across the full range of expected exposures. At a
minimum, the method must have a lower quantitation limit of one
half the NCEL (instead of 0.1 x NCEL) and an upper quantitation
capability of twice the NCEL (instead of 2,000 x NCEL). This new
range is consistent with existing OSHA rules. If, however, the
company obtains a monitoring sample that is more than 10% above the
upper quantitation limit of the analytical method, exposed workers
must wear a 19-C supplied-air respirator. Of course, the company
may decide to use a self-contained breathing apparatus (SCBA) when
very high exposures are present due to emergency or other
conditions (see paragraphs (d)(5) and (e)(2) of the revised '5(e)
Order provisions).
C. Method Performance Requirements
1. Comment (NIOSH) : Paragraph (4) (iv) (page 17); Specifies
spiking at 0.5, 1.0, and 2.0 times the NCEL to determine the
percent recovery. NIOSH methods development procedures also call
for spiking at 0.1 times the selected level.
2. Comment (NIOSH): Precision - relative difference: The
calculation of relative percent difference (RPD) is not complete.
The resulting value from the calculation should be multiplied by
100. RPD does not convey much information about method precision.
A method with an RPD of 40% would have a relative standard
deviation (RSD) of 27.9%. This is not very precise.
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3. Comment (NIOSH): Calculated percent recovery: What is meant
by controlled environment? The number of samples specified for
calculating percent recovery do not provide much statistical power
for assessing percent recovery. During method development, at
least 5 matrix spikes should be run each at 0.5 NCEL, at NCEL, at
2 times NCEL. It also would be useful to run 6 spikes at the NQL.
(This range does not agree with the range specified on page 16.)
During method development, the calculated percent of recovery is
to be determined by at least 7 matrix spikes over the range 0.5 to
2 times the NCEL. This range does not agree with the range
specified on page 16. Specifications for the recoveries of matrix
spikes analyzed during subsequent monitoring also should be stated.
4. Comment (NIOSH): Desorption efficiency and sample storage
study (pages 18-19): How does "desorption efficiency" differ in
principal from "calculated percent recovery?" The requirements for
storage studies do not specify the length of storage (e.g., for 30
days to accommodate sample shipment and lab delays).
5. Comment (OSHA) : Section B. (4) (iv) states that the percent
recovery for a matrix spike must be at least 70%, while section
B.(4)(vi) states that the desorption efficiency must be at least
75%. When adsorbent tube samplers are used, the "matrix spikes,"
at the NCEL, of section B. (4) (iv) and the desorption efficiency
samples of section B. (4) (vi) are identical, therefore is the
different criteria of 70% in Section B.(4)(iv) and 75% in section
B.(4)(vi) intentional? The 70% criteria for the matrix spikes of
section B.(4)(iv) that are at 0.5 the NCEL may be appropriate for
allowing for the slight drop in desorption efficiency for smaller
sampler loadings, which is sometimes typical.
6. Comment (SPI): One must be able to demonstrate that (1) the
samples are quantitative, (2) repeatable, and (3) predictable. The
first refers to the fact that sampling methods should recover a
fixed amount or proportion of a known quantity of material under
specified conditions. The second refers to the fact that under
specified conditions, the method should recover the same quantity
of material. The last indicates that one should be able to predict
on the basis of observable facts what the correction factor should
be. One hundred percent recovery is not only infeasible, it is
scientifically unnecessary.
So long as one can be sure that, for example 50% of a material
is recovered, simple arithmetic can compensate for the
methodological inefficiency. This is what is meant by systematic
bias in statistics and is of no concern with respect to the purpose
of workplace monitoring--the assurance of protection of workers.
Moreover, if we know that other factors will change sampling
efficiency, such as humidity with many methods, we need only add
that factor into our arithmetic to compensate for the imperfection
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of human observation. The key is being able to relate what is in
the air to what is happening to the worker.
EPA Response: EPA has added spiking levels to the method
development criteria for matrix spikes and has followed NIOSH
method development criteria. Direct spiking of the sampling
cartridge or controlled atmosphere studies can provide this
information. Matrix spikes using direct spiking followed by the
passage of a certain volume of air or controlled atmosphere studies
must meet a 75% to 125% recovery criteria. Desorption efficiencies
are generally determined from direct spiking on the adsorbent tube.
Desorption efficiencies must be 75% or greater. Precision
requirements have been changed to incorporate the NIOSH/OSHA
precision and accuracy targets. For example, accuracy has been
defined as + 25% with 95% confidence. This will eliminate the
relative percent difference (RPD) issue. A precise method is
desirable, but low recoveries (<60%) bring into question the actual
adequacy of the method. EPA has allowed for the correction of
recoveries within certain limits.
D. NCELs Quality Assurance Requirements
1. Comment (ETAD): Second, the quality assurance ("QA")
requirements in the proposed NCELs program differ from, and are far
more stringent than, current OSHA good laboratory practices ("GLP")
requirements. There is no justification for imposing different and
more stringent requirements on new chemicals than on existing
chemicals. This is a particular concern of the dye industry, which
is responsible for a significant number of PMN submissions and
therefore would be affected to a greater extent than many other
industries. EPA should follow the OSHA GLP requirements in its
NCELs program.
2. Comment (SOCMA): The quality assurance ("QA") requirements
contained in the proposed NCELs program differ from, and are far
more stringent than, current OSHA good laboratory practices ("GLP")
requirements. SOCMA submits that there is no material difference
between workplace exposure to new chemicals and existing
chemicals to justify EPA imposing different and more burdensome QA
requirements. EPA should follow the OSHA GLP requirements in its
NCELs program.
3. Comment (CMA) : The burdens associated with method development
will be magnified by the level of detail required in Part B of the
proposed NCELs program ("Approval of Sampling and Analytical
Method") and the inclusion of the OPPT Guidance Document for the
Preparation of Quality Assurance Project Plans in the appendix.
Stringent quality assurance requirements for sampling and analysis
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in the new chemical program will not add to the quality of the data
collected, but rather will unnecessarily increase costs.
4. Comment (CMA) : In this regard, major changes in standard
industrial hygiene practices would be necessary as a result of
EPA's proposal to require the use of Good Laboratory Practice (GLP)
requirements under TSCA, not only for analytical methods
development but for the collection and analysis of workplace
samples. No comparable requirements have been imposed under OSHA
standards. OSHA regulations identify a level of quality control
that must be met, not how that level of quality control is met.
AIHA approves certain Industrial Hygiene laboratories that
demonstrates they meet certain levels of quality assurance. While
laboratories accredited by AIHA now have adequate quality assurance
programs, they would not necessarily meet the stringent standards
of EPA's GLP regulations. Monitoring the practices of certified
laboratories to conform to the EPA requirements would be
disruptive, costly and unnecessary, particularly in view of the
absence of comparable GLP requirements in existing OSHA regulations
establishing workplace limits.
5. Comment (SOCMA): The proposed NCELs program would impose very
specific, burdensome and costly recordkeeping and reporting
requirements on regulated parties. However, much of the same
information could be obtained in a much less burdensome and costly
manner through the use of existing laboratory standard operating
procedures ("SOPs"). EPA should include a mechanism allowing the
use of SOPs in lieu of NCELs procedures where comparable.
6. Comment (SPI): The quality assurance (QA)/quality control
(QC) methods appear to mirror Superfund criteria. These may be
acceptable for existing chemicals where QA methods have long been
established and formalized but are not practical for new chemicals.
7. Comment (SPI) : The QA requirements also go beyond current
OSHA or EPA GLP requirements under other statutes administered by
the Agency, e.g., FIFRA.
The NCEL approach as drafted will not alleviate the burdens
posed by the existing 5(e) consent order process and may place new
burdens on affected companies. Additionally, there may be a
loophole in the NCEL approach if the production is halted at
appropriate intervals levels.
8. Comment (SPI): Page 3, paragraph (d) - It is unclear whether
this paragraph means both sampling and analytical must meet EPA GLP
requirements. We would not expect EPA to review a sampling
strategy before samples are collected. We anticipate EPA will only
want the analytical and general sampling plan. The time and effort
required to develop a new analytical method could be as much as 180
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days for method development and validation (30-60 days with storage
evaluation data, 30-60 days for internal review and approval and
15-60 days for collection of monitoring samples and analysis of
these samples).
9. Comment (SPI) : EPA GLPs are not necessary if the standard
requires the documentation of accuracy and precision as noted
above. Moreover, many of the requirements found in the GLPs are
necessary for performing scientific studies where the purpose is to
carefully control a limited number of independent variables. This
is not the case in workplace air sampling and monitoring. Rather,
here the objective is more akin to quality control sampling: the
hypothesis to be tested is whether the exposures are above the
limits. EPA should not be concerned how much below, or precisely
how much above the NCEL exposures are, so long as the correct
decision regarding protective equipment and the adequacy of the
controls can be made. EPA should keep in mind that increases in
scientific certainty come at a significant cost, and in some cases,
such as this, the increased information adds nothing to the
decision making process that is to be followed.
EPA Response: OSHA does not require GLPs. However, the American
Industrial Hygiene Association (AIHA) Industrial Hygiene Laboratory
Accreditation Program (IHLAP) was created in response to requests
from OSHA and NIOSH to ensure the availability of labs providing
reliable IH data to document compliance with OSHA PELs. The AIHA
IHLAP has accredited over 300 labs.
TSCA GLPS are designed to specify minimum procedures to ensure
accurate data. According to 40 CFR 792.1(c), "[i]t is the Agency's
policy that all data developed under section 5 of TSCA should be in
accordance with" TSCA GLPS. Therefore, EPA has retained the
requirement for compliance with TSCA GLPS. However, EPA recognizes
that routine IH monitoring is not the typical "study" for which
TSCA GLPS are required, and that there are alternative ways to
ensure accurate data. Therefore, EPA has revised this requirement
to accept use of a laboratory accredited by the AIHA IHLAP, or
another comparable program approved in advance in writing by EPA,
as an alternative to compliance with TSCA GLPS.
EPA has also revised the NCELs provisions to clarify that:
(1) the contents of the sampling and analytical method no longer
must satisfy specified portions of the OTS Guidance Document for
the Preparation of Quality Assurance Project Plans; (2) TSCA GLPS
do not apply to NCELs method development ("The term 'study' does
not include basic exploratory studies carried out to determine
whether a test substance or a test method has any potential
utility." 40 CFR 792.3), but do apply to method verification and
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actual monitoring; and (3) certain provisions of the TSCA GLPS
related to toxicity testing in laboratory animals, such as 40 CFR
792.43 ("Test system care facilities"), 792.45 ("Test system supply
facilities") and 792.90 ("Animal and other test system care"), are
clearly inapplicable to the NCELs requirements.
E. Sampling Device Capacity
1. Comment (NIOSH): Sampling device capacity (page 18); in order
to determine sampler capacity, the flow rate at which the analyte
is collected should be specified, along with volume and mass of
analyte. The humidity used for capacity determination should be
appropriate to each analyte. In many instances, high relative
humidity reduces the capacity of a sorbent for an analyte, but in
some cases, low humidity may be more restrictive.
2. Comment (OSHA) : Because it is possible to have a sampler
whose capacity is enhanced by humidity, it may be appropriate to
include a requirement in section B.(4)(v) which specifies that if
humidity is determined to enhance sampler capacity, the capacity
tests should be performed with dry air, which would be the worst-
case condition. We currently have two methods development projects
in progress, one for methanol and one for phthalic anhydride, in
which we have found sampler capacity significantly enhanced by
increased humidity.
3. Comment (SPI) : A relative humidity of 80% may not be
compatible with the properties of the substance being measured.
Collection efficiency of the collection device needs to
be taken into account.
"You must take sample without any loss." That is totally
infeasible, even with the most innovative sampling
techniques.
4. Comment (SPI): Representativeness requirement may not be
consistent with the humidity requirement on p. 18.
5. Comment (CMA) : Page 18: The requirement that sampling
devices must be capable of collecting samples without loss is
impractical. Studies of three weeks in length are sufficient to
determine any loss due to storage. Change "absorbent" to
"adsorbent." For adsorbent tube monitoring, breakthrough should be
defined as greater than 25% of the analyte detected in the backup
section rather than 5% of upstream concentration. This standard is
used by professional industrial hygienists and industrial hygiene
laboratories. It is far easier to analyze a backup section of a
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sampling tube or filter than to determine upstream headspace
concentrations.
Must the sampling device capacity and desorption efficiency be
determined in a controlled environment (generating a known vapor
concentration), or can these factors be determined by drawing a
known volume of air through a matrix spike? CMA believes this
choice should be left to the discretion of the laboratory
responsible for developing the method as long as appropriate
documentation is available.
6. Comment (CMA): Page 19: Can either vapor-generated or matrix
spikes be used to determine relative percent difference?
7. Comment (CMA) : If less than a 30% difference is seen in
percent recovery or in the sampling device capacity at low humidity
(5-25%) and high humidity (75-95%), then the method should be
deemed valid at any humidity level. (Corrections of up to 30%
should be applied based on the data generated in the humidity
studies.) If the difference between the results is more than 30%,
then a mid-range (40-60%) relative humidity study is recommended.
Corrections for humidity differences will be made based on the
three data points generated.
Section (8) on representativeness is too restrictive. While
different workplaces may have different environments, it is not
necessary to test them all. A laboratory will review the method to
avoid interferences. As long as high humidity is taken into
consideration, other changes in the environment (i.e., lighting,
presence of other chemicals) would not normally affect the method.
EPA Response: In instances where sampler capacity is enhanced by
high humidity, the capacity determination should be conducted with
dry air. In general, humidity requirements have been changed to be
more practical, but the humidity used for capacity determination
should be appropriate to each analyte. The NCELs language has been
revised to be more consistent with NIOSH and OSHA. Methods using
adsorbent tubes as the collection medium are allowed, provided
evidence of the capacity is provided in the form of breakthrough
testing. The efficiency of the collection device has been
considered and addressed in the NCELs language. EPA encourages
companies to include these types of details in their written
description of the analytical method.
F. Fiber Structure
1. Comment (NIOSH): Page 21: "... the fiber chemical
composition and nature..." This section should also include an
additional requirement about the physical nature or structure of
the fiber, specifically how does the fiber behave (does it split
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longitudinally into additional fibers or smaller diameters?).
Also, the surface properties of the fiber are important and may not
be included in the term "chemical composition and nature."
2. Comment (Labor) : Item 10 on Fibers (pp 21-22) fails to
address the respirability of fibers. Since the NCEL focus rests on
inhalation exposures, and presumably hazards/health effects
resulting from inhalation, an NCELs for a fiber must be based on a
TWA for fiber sizes which are respirable. Thus, the sampling and
analytical methods developed or used must define what is a
respirable fiber (i.e., fiber diameter and aspect ratio) for
establishing an NCEL.
3. Comment (Labor) : If the characterization of fiber size
distribution performed on both bulk fiber and on air samples
collected in the workplace (as called for in this draft) establish
that no respirable fibers are present, then an NCEL for total dust
should be developed.
4. Comment (CMA): Page 21: Transmission electron microscopy
should not be required for fiber analysis. Analysis by light
microscopy is sufficient.
5. Comment (SPI): "Fibers" needs to be defined. There should be
threshold parameters for this definition.
EPA Response: EPA has deleted the paragraph pertaining to fibers.
G. Continuing Calibration
1. Comment (NIOSH) : Instrument calibration (page 17) : Weekly
calibration of a method is too infrequent. NIOSH calibration
standards are typically intermixed with samples to account for
minimal instrument variation during analysis. The method is then
calibrated after the analyses are completed. For the "initial"
calibration curve, the lowest chemical standard should be below the
NQL, not at the NQL. In fact, a chemical standard should not be at
or below the LOD concentration.
2. Comment (CMA) : Page 17: What does the term "continuing
calibration sample" mean in this context? Does it refer to a
standard that is used from one week to the next, to a new standard
made up each week that samples are compared to, or is some other
meaning intended?
EPA Response: Calibration must be conducted before analyses and
every tenth sample during analysis. These calibrations are
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conducted to assess instrument stability. A calibration sample
refers to a standard close to the NCEL, which is run with every
batch of samples and used to establish a time limit associated with
the stability of the standards.
H. Definitions
I. Comment (NIOSH): Limit of detection (LOD) (page 16): ACS or
NIOSH definitions should be considered. We have enclosed recently
finalized NIOSH standard operating procedures for industrial
hygiene sampling and chemical analysis that include NIOSH
definitions for LOD and LOQ.
2. Comment (SPI): The duplicate sample definitions needs to be
clarified.
EPA Response: EPA has made these definition consistent with NIOSH
and the American Chemical Society (ACS).
I. NCEL below LOD
1. Comment (CMA): If the development of the analytical method
indicates that the NCEL is below the limit of detection, a
mechanism must be available for companies to meet with EPA and
negotiate a change in the proposed limit.
EPA Response: The NCELs option will not be possible if the method
cannot reliably measure the action level. A re-evaluation of the
NCEL may be possible based on the health risks and technological
feasibility, but an upward adjustment of the NCEL cannot be
guaranteed.
J. Sampling Intervals
1. Comment: NCEL Flow Chart - The requirement that periodic
monitoring should be continued until two samples, not less than
seven days apart, are below the action level is unscientific. A
more correct approach is to require that the samples be
representative of the exposure of the workers who are being
protected. The question is one of selecting an unbiased sample to
reflect accurately the exposure being monitored, and an arbitrary
seven day period between samples is no more scientific than any
other arbitrary period. Selecting an unbiased sample period is not
a question of proximity in time, but of being able to support the
conclusion that the data are accurate by observations showing that
the selection of the sample period was unbiased.
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It is equally likely that for most processes under the right
circumstances, two samples collected on consecutive days may be
more representative of the worker's total exposure than two samples
taken seven days or more apart. EPA should not specify a time
period, but should require only that there be some objective
evidence that the samples collected are representative.
2. Comment: Page 25: The requirement in Section (3) for taking
measurements at least seven days apart should be revised. Samples
should be taken when an operation is running and when the
opportunity for exposure is high, rather than at a set interval of
seven days.
EPA Response: The flow chart has been deleted. EPA's revisions to
the NCELs provisions reduce the monitoring requirement for
"Reductions in Respiratory Protection" and "Terminations of
Periodic Monitoring" from two consecutive measurements at least 7
days apart (as required by OSHA) to two consecutive measurements at
least 24 hours apart for batch production processes of durations
less than 7 days, provided that these measurements accurately
reflect the highest peak exposures and variability in exposure.
K. Changes Affecting Validity of the Method
1. Comment (SPI): Page 20 (9) - "Changes affecting validity" are
difficult to manage and enforce. This requirement needs further
clarification.
2. Comment (CMA): A further disincentive to using the NCELs
process is the proposed requirement to revalidate sampling and
analytical methods where "changes in the workplace environment"
could affect the validity of those methods. As proposed, this
open-ended approach could require revalidation, with all the
attendant effort and expense, in situations where changes in the
workplace are unlikely to affect a method's validity. A better
approach is to require revalidation only where there is strong
evidence to suspect that a workplace change will in fact impair the
method's validity--i.e., when a new compound introduced to the
workplace environment is known to interfere with detection of the
PMN substance.
EPA Response: EPA agrees and has amended the language to place the
responsibility upon industry to revalidate the method when changes
in the workplace are reasonably likely to invalidate the accuracy
of the sampling and analytical method.
L. Other Sampling Methods
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1. Comment (NIOSH): Approval of sampling and analytical methods
(page 15): section should include reference to interferents that
may influence the analytical outcome. The section is oriented to
solid sorbent media collection. Other collection media should be
addressed as well.
2. Comment (SPI): The NCEL language should be more generically
written so that a company would have more latitude in determining
the type and quantity of air monitoring to be accomplished.
EPA Response: The section in question has been revised to be less
focused on any one particular methodology and more inclusive of
other available sampling methodologies.
M. Measurement Properties
1. Comment (NIOSH): Contents of submission (page 15): The text
should refer to "chemical and physical properties" of the given
substance rather than "Properties pertinent to its measurement."
EPA Response: The "contents of submission" provision has been
deleted.
V. MONITORING REQUIREMENTS
1. Comment (SPI): NCEL Flow Chart - The requirement that periodic
monitoring should be continued until two samples, not less than
seven days apart, are below the action levels is unscientific. A
more correct approach is to require that the samples be
representative of the exposure of the workers who are being
protected. The question is one of selecting an unbiased sample to
reflect accurately the exposure being monitored, and an arbitrary
seven day period between samples is no more scientific than any
other arbitrary period. Selecting an unbiased sample period is not
a question of proximity in time, but of being able to support the
conclusion that the data are accurate by observations showing that
the selection of the sample period was unbiased.
It is equally likely that for most processes under the right
circumstances, two samples collected on consecutive days may be
more representative of the worker's total exposure than two samples
taken seven days or more apart. EPA should not specify a time
period, but should require only that there be some objective
evidence that the samples collected are representative.
2. Comment (CMA) : Page 25: The requirement in Section (3) for
taking measurements at least seven days apart should be revised.
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Samples should be taken when an operation is running and when the
opportunity for exposure is high, rather than at a set interval of
seven days.
EPA Response: EPA's revisions to the NCELs provisions reduce the
monitoring requirement for "Reductions in Respiratory Protection"
and "Termination of Periodic Monitoring" from 2 consecutive
measurements at least 7 days apart (as required by OSHA) , to 2
consecutive measurements at least 24 hours apart for batch
production processes of durations less than 7 days, provided that
these measurements accurately reflect the highest peak exposures
and variability in exposure.
3. Comment (SOCMA): The NCELs Flow chart indicates that periodic
monitoring is required at least every 6 months if two consecutive
measurements below the acceptable limit at least 7 days apart
cannot be obtained. This suggests that if the initial measurement
exceeds the acceptable limit, workers would be required to wear
respirators for 7 days pending the second measurement. EPA should
provide an employer with the option of taking a second measurement
immediately upon receipt of the result of the first to determine
whether the initial reading was due to an analytical error, an
unusual circumstance, or was a "true" reading of workplace
exposure.
4. Comment (CMA): The monitoring requirements are numerous,
variable, and often vague. The immense effort to achieve
compliance, in addition to the considerable requirements for
recordkeeping, is not conducive to industry adoption. For example,
if a chemical is detected at a concentration that is over the
"acceptable limit," does the company collect two samples, 7 days
apart? If so, what protection is required for workers between
these sampling events, i.e., must respirators be worn for 7 days?
CMA believes that immediate remeasurement following detection of
an unacceptable concentration should be allowed in the proposed
requirement to determine if the initial result represented a "blip"
(such as a process upset) or is indicative of normal operations.
The periodic monitoring requirements are not sufficiently
flexible for companies who use batch processes. In addition,
monitoring in the event of a spill is unrealistic--it would be
preferable to have protected personnel clean up the spill
immediately, rather than wait until the monitoring team arrives to
take samples.
EPA Response: The flow chart was intended to help illustrate the
relations between the various NCELs provisions. It has been
deleted.
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The NCELs requirements were derived from OSHA existing
requirements, with modifications made where appropriate. The "2
consecutive measurements taken seven days apart" language was
copied from OSHA comprehensive standards. If a company wants to
decrease the monitoring or respirator requirements after a chemical
is detected at a concentration that is over the NCEL, the company
would need to collect two samples, seven days apart. In this
event, appropriate personal protective equipment, including
respirators, would have to be worn during the intervening seven
days if workers would otherwise be exposed to the PMN substance.
The language is sufficiently flexible for batch processes as
it only requires monitoring in the event the substance is actually
being manufactured, processed, or used during a specified
monitoring period. Additionally, EPA's revisions to the NCELs
provisions reduce the monitoring requirement for "Reductions in
Respiratory Protection" and "Termination of Periodic Monitoring"
from 2 consecutive measurements at least 7 days apart (as required
by OSHA), to 2 consecutive measurements at least 24 hours apart for
batch production processes of durations less than 7 days, provided
that these measurements accurately reflect the highest peak
exposures and variability in exposure.
The NCELs language applicable to spills has been modified to
enable appropriate clean-up efforts to take place, with workers
wearing appropriate personal protective equipment before, or in
conjunction with monitoring.
5. Comment (Labor): In general, we endorse the proposed "New
Chemical Exposure Limits" section as an alternative to be used to
address inhalation hazards. This can represent a major step
forward for worker protection owing to the inherent questionable
reliability of respiratory protection programs. However, the very
nature of a "new chemical substance" infers a certain lack of
knowledge regarding human exposure health consequences both acute
and more troubling, chronic, which places an added burden on both
EPA and the employer with regard to worker protection. In that
regard, the NCEL approach must be based upon this recognition.
Considering this, the proposed periodic monitoring requirement of
every 6 months unless E(5) [now (d)(5)] is triggered, is seriously
deficient. Further, additional monitoring "within 7 days" if E(5)
is triggered is likewise deficient. A substantial change in the
monitoring requirements is needed. Periodic monitoring should also
be based upon or keyed to the Action Level.
EPA Response: The monitoring requirements were developed based on
existing monitoring requirements in OSHA standards, such as for
benzene (29 CFR 1910.1028). The periodic monitoring requirements
for OSHA standards vary from no requirements (29 CFR 1910.1000) to
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monthly, quarterly, every 6 months, or annually. For example,
OSHA's benzene standard requires periodic monitoring at least every
six months, triggered by measurements above the TWA, but only
annually for measurements between the TWA and the action level.
EPA, in the NCELs language, has strived to maintain consistency
with the OSHA requirements, as appropriate. EPA considers 6 months
to be a reasonable period of time in which to take such
measurements when prior monitoring did not exceed the NCEL, and
represents an average or median value among the differing OSHA
monitoring requirements. However, where prior monitoring exceeds
the NCEL, EPA has revised the NCELs provisions to require periodic
monitoring every 3 months.
EPA has modified the language to address the comment regarding
"within 7 days" to clarify that monitoring shall take place within
7 days of: (1) a change in the production volume, process, control
equipment, personnel or work practices that may reasonably cause
new or additional exposures to the PMN substance, (2) spills,
leaks, ruptures or other breakdowns which occur that may reasonably
cause new or additional exposures to the PMN substance, or (3) when
the company has any reason to believe or suspect a change that may
reasonably result in new or additional exposures to the PMN
substance. Additional language makes clear that in no event is the
additional monitoring requirement in subparagraph (d) (5) (a)
intended to delay implementation of any necessary cleanup or other
remedial action. During any such operations that may occur before
commencing additional monitoring, the company shall ensure that
potentially exposed persons use at least the respiratory protection
specified in subsection (d) based on the measured airborne
concentration, or more protective respiratory equipment deemed
appropriate by the best professional judgment of a technically
qualified expert. The modifications are more consistent with
existing OSHA standards.
6. Comment (SPI): The NCELs language should be more generically
written so that a company would have more latitude in determining
the type and quantity of air monitoring to be accomplished.
EPA Response: The requirements are consistent with current OSHA
requirements. There is sufficient latitude within the requirements
to accommodate changes in production. If the OSHA requirements for
monitoring are revised, EPA will re-evaluate the NCELs
requirements. EPA is also aware that OSHA is currently developing
a Generic Exposure Monitoring Standard which, if appropriate, could
be adopted by EPA.
NOTE: Supplemental comments were submitted by CMA in March
1993 (not included verbatim here) the primary gist of which was to
urge that EPA should allow statistical approaches to analyses of
monitoring results. Again, this would go beyond current OSHA
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requirements, and EPA will generally defer to OSHA's lead in
developing policy on regulating workplace exposures. EPA may
explore the subject further if resources become available.
7. Comment (SPI): There may be a loophole in the NCEL approach if
the production is halted at appropriate interval levels.
EPA Response: The NCELs language does not require monitoring if
the substance is not manufactured, processed or used during a given
6-month calendar period.
8. Comment (SPI): Given the potential overlap with OSHA, we urge
EPA to defer to OSHA regarding the air monitoring and workplace
control aspects discussed in the draft order.
EPA Response: EPA is required by law to administer Section 5 of
TSCA, and to the extent that the Agency's mandate is to prevent,
among other things, unreasonable risk to human health, it is well
within EPA's purview to impose requirements to effect risk
reduction which may occasionally overlap with OSHA requirements.
The NCELs general monitoring requirements are based on existing
OSHA requirements for protecting workers from airborne exposure to
chemicals and are consistent with OSHA regulations designed for
that very purpose. EPA will consider changes made to OSHA
monitoring and workplace control requirements in the NCELs program.
9. Comment (NIOSH): Should include provision for exposure regimes
of more than 8 hours duration.
10. Comment (SPI) : Page 22 - It is unclear in the draft how a
company would handle workshifts of more than 8 hours. One may have
to ratio down the TWA or leave it the same.
Page 22-c(l) - Where increased workshift schedules exist, an
8 hour-TWA will not be adequate.
Page 27-8 hour-TWA - Alternative workshifts need to be
considered here too.
EPA Response: EPA has elected to establish New Chemical Exposure
Limits based on the conventional 8-hour day, 40 hour work week, as
is commonly done for exposure limits set by the ACGIH and OSHA.
However, EPA recognizes that other work regimes may exist and
protection provided should be equivalent to that provided to
workers with conventional schedules. There is guidance presented
in both the ACGIH TLV Handbook and in Patty's Industrial Hygiene
and Toxicology (standard industrial hygiene reference texts). EPA
suggests that these references or other equivalent references be
consulted to address this issue. These approaches reduce the
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exposure limit proportionally for increased exposure time, and for
reduced recovery (non-exposure) time.
11. Comment (SPI) : The period should be defined to determine
changes in production volume.
EPA Response: The requirements for periods of measurement were
based on existing OSHA requirements, with minor modifications made
as necessary to allow flexibility for small volume, batch
operations. The language has been clarified to reflect the OSHA
language on monitoring. This will clarify the sampling
requirements and help in maintaining consistency with applicable
OSHA requirements. The language addressing spills has been
modified to be more consistent with existing OSHA requirements.
The language is sufficiently flexible for batch processes as it
only requires monitoring if the substance is actually being
manufactured, processed, or used.
12. Comment (Labor): Periodic monitoring should also be based
upon or keyed to the Action Level.
EPA Response: Monitoring is keyed to both the action level and the
time weighted average (TWA).
13. Comment (SPI): "Exposure" can't be sampled, the concentration
in air can. A value less than the detection limit should not be
equated to the limit for the purposes of this order.
EPA Response: Section (d)(1)(ii) of the NCELs provisions states
that "...the Company shall take representative samples of what the
potential exposure of each person who is reasonably likely to be
exposed to airborne concentrations of the PMN substance would be if
respirators were not worn."
VI. RESPIRATORY PROTECTION
1. Comment (NIOSH): The selection of appropriate respiratory
protection in the absence of data on toxicity and "immediately
dangerous to life and health" (IDLH) characteristics would suggest
that positive pressure respirators would be the minimum starting
point for respirator selection [NIOSH 1987].
EPA Response: EPA does consider potential health effects and
toxicity when selecting respiratory protection. The procedures
used for selecting respirators are based on NIOSH recommendations
in the "Strategy for Recommending Respirators for Control of
Exposures to Substances Undergoing Premanufacture (PMN) Review" and
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the NIOSH Respirator Decision Logic (1987). Where appropriate, EPA
will allow use of respirators which are not positive pressure for
new chemical substances. This determination is based on
information provided in the PMN, methodologies used by EPA for
evaluating potential human health effects and occupational
exposure, and experience gained in reviewing over 20,000 PMNs. Due
to a lack of toxicity and exposure data on the substance, EPA
assessments tend to err on the conservative (i.e., protective)
side, such that potential exposures and hazards are generally over-
estimated. If, based on these conservative estimates, a positive
pressure device is not needed, EPA will allow the use of negative
pressure devices.
EPA generally does not have the information to determine IDLH
exposure conditions for PMN substances, and requires the PMN
submitter to select the appropriate NIOSH-approved respirator in
accordance with 29 CFR 1910.134, the Respiratory Protection
standard. Concern due to acute health effects is very rare in the
New Chemicals Program. In fact, of the about ten '5(e) Orders
issued to date containing NCELs provisions, all have been concerned
exclusively with chronic effects and none have included a short
term exposure limit (STEL).
2. Comment (SPI): Page 24-25- The measured concentrations appear
without justification.
EPA Response: These concentrations were developed based on the
NIOSH Assigned Protection Factors as given in the NIOSH Respirator
Decision Logic, 1987. The NIOSH Assigned Protection Factor is
defined as "the minimum anticipated protection provided by a
properly functioning respirator or class of respirators to a given
percentage of properly fitted and trained users" (NIOSH, 1987) .
3. Comment (Labor): Tables, page 33-37: There is no difference
in the need to know cartridge performance data between an "organic
vapor" cartridge (page 36) and a "paint spray" cartridge (page 33).
Why is the "Paint Spray Mist Exposure" table not headed by a
requirement for performances data submission and approval by EPA?
All the respirators listed on the page 35 table are SARs. They
have no cartridges. Why the requirement for submission of
cartridge data?
These tables could be replaced with the NIOSH Revised RDL
Tables.
EPA Response: The requirement for cartridge testing is determined
on a case-by-case basis. In general, most PMN substances used in
paint spray applications occur in the particulate or mist form,
rather than in vapor form, and organic vapor cartridge testing is
not needed for the particulate form. With substances for which EPA
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is concerned about vapor exposure and the company wishes to select
an air-purifying respirator, cartridge testing would be required.
VII. RECORDKEEPING
1. Comment (CMA): Adding to monitoring burdens is the requirement
that companies discontinue monitoring for a particular exposure
group and prepare an annual report documenting the absence of
workplace changes (that could result in increases in exposure). No
comparable requirement is imposed under OSHA standards. Here
again, consistency with the OSHA approach will eliminate
unnecessary burdens. The purpose of discontinuing periodic
monitoring where exposures are below the action level is to
minimize compliance burdens in workplaces that pose low risks to
employees. This purpose would be largely nullified if such
workplaces are subject to continual reporting and recordkeeping
requirements that assure exposure levels remain low.
EPA Response: EPA acknowledges that the requirement that companies
submit an annual report following termination of monitoring does go
beyond what OSHA currently requires. Therefore, with an eye
towards streamlining NCELs to establish a closer alignment with
OSHA PELs, and hence increase its acceptance by the regulated
community, EPA has chosen to delete this requirement.
2. Comment (CMA): The recordkeeping requirements included in
EPA's proposed consent order are also more elaborate than the
comparable provisions of OSHA standards. While full records of
workplace monitoring should be retained, EPA's proposed consent
order would require additional documentation that could be quite
extensive. Companies must retain records of "any condition that
might have affected the monitoring results" and of "any actions
taken to mitigate exposures to the PMN substance." Records
documenting "any spills, leaks, ruptures or other breakdowns that
may cause new or additional exposure" must also be retained. These
requirements, in CMA's judgment, are excessive and should be
streamlined so they parallel the comparable provisions of OSHA
standards.
3. Comment (SPI): The NCEL proposal will present compliance
difficulties, especially with respect to much detailed
recordkeeping and reporting. The guidance document provides
several good suggestions but carrying out all the requirements will
put undue and unnecessary burden on those subject to 5(e) Orders as
well as add substantial costs which may prohibit market entry of
new chemicals.
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EPA Response: EPA has attempted to keep the NCELs recordkeeping
requirements to a minimum necessary for viable compliance
monitoring and enforcement. For example, to document that workers
are in fact being adequately protected, it is essential to keep
records of monitoring results, as well as grounds for termination
or resumption of monitoring. In general, the recordkeeping
requirements comport with good business practice and would be
required to be maintained under the Occupational and Safety Health
Act and regulations as well as by some private insurers.
4. Comment (CMA): Page 30, 58: Because of the proprietary nature
of the information requested here, EPA must be prepared to either
keep this confidential, or allow companies to maintain records in-
house and make them available upon request for inspection.
EPA Response: The language in the recordkeeping section of the
NCELs portion of the Consent Order is clear that records are in
fact to be maintained in-house by the company, and made available
to EPA upon request for inspection. The company is not otherwise
required to submit these records to EPA.
5. Comment (Labor): This section should be modified to: (a) Note
that even when using a "new chemical" an employer is still
responsible for providing a safe and healthful work environment per
the OSHA regulations; (b) The OSHA Recordkeeping requirements, and
access thereto, are governed by 29 CFR 1910.20. The 5 year
recordkeeping requirement noted, for example, violates 1910.20.
EPA Response: Since existing OSHA regulations already require
these employee exposure records to be kept for 30 years, EPA will
do likewise. Title 29 CFR 1910.20(d)(ii) requires employers to
keep employee exposure records for 30 years for employees exposed
to "toxic substances or harmful physical agents." 29 CFR
1910.20(b) (1) . "Toxic substances or harmful physical agents" are
defined at 1910.20(c) (13) to include any chemical substance which:
(i) Is listed in the NIOSH Registry of Toxic Effects of Chemical
Substances (RTECS); (ii) Has yielded positive evidence of an acute
or chronic health hazard in testing; or (iii) Is the subject of
a material safety data sheet (MSDS) indicating that the material
may pose a hazard to human health. Since all NCELs '5(e) Orders
require an MSDS indicating a potential health hazard, the 30 year
recordkeeping requirement under 29 CFR 1910.20 will automatically
apply to the PMN substance.
Since OSHA and EPA may both have jurisdiction simultaneously,
the company would still be required to comply with OSHA's 30 year
requirement, even if EPA only imposed a 5 year requirement. Since
the company is therefore required by OSHA to keep these records for
30 years, EPA has decided to revise its NCELs recordkeeping
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requirement to harmonize it with OSHA and require the company to
keep NCELs exposure records for 30 years.
VI. MISCELLANEOUS
1. Comment (SPI): The NCEL approach as drafted will not alleviate
the burdens posed by the existing 5(e) Consent Order process and
may place new burdens on affected companies.
2. Comment (CMA) : CMA supports the concept of NCELS but believes
its implementation should be streamlined. As proposed, the NCELs
concept could cause lengthy delays in the finalization of the
Section 5(e) Orders and place unreasonable administrative burdens
on manufacturers.
EPA Response: Largely in response to comments received by outside
parties, EPA has revised the NCELs program to make it less
burdensome on industry while still providing adequate protection to
workers. Such changes include, among other things, modification of
analytical requirements, allowance of reliance on objective data,
and deletion of the requirement that companies prepare an annual
report after monitoring is terminated.
3. Comment (SOCMA): SOCMA would appreciate an opportunity to meet
with you at your convenience to discuss in more detail the
technical and procedural issues outlined in these comments.
EPA Response: The need for such a meeting may be obviated by the
revisions EPA has made to the NCELs program. Should this not be
the case, EPA welcomes the opportunity to meet with interested
parties.
4. Comment (SOCMA): The regulated community should be provided an
opportunity to review and comment on the revised program prior to
its adoption.
EPA Response: The NCELs requirements have undergone a lengthy
review process. EPA believes that all interests are best served by
EPA implementing the revised NCELs program immediately, without
further delay. Unlike rulemaking activity, however, development of
'5(e) Consent Orders contemplates an evolving case-specific
approach. If necessary, the specific terms of individual '5(e)
Orders may be negotiated so that their terms are more appropriately
tailored to the specific facts of an individual PMN case.
Additional information which is brought to the Agency's attention
by the submitter is always considered. Upfront submission of
comprehensive information in the PMN submitter's possession and
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control will therefore greatly enhance the precision of the
Agency's risk assessment and ensuing regulatory controls.
5. Comment (Labor) : Action Level: E (1) (i) does not define the
action level. Is it 50% of the NCEL or different for each new
chemical based upon EPA's review?
EPA Response: The "action level" is always half the NCEL. The
generic '5(e) Order language has been revised to reflect this.
6. Comment (SPI): There are some flaws in the flow chart:
(a) there is always the possibility of a process change or
breakdown.
(b) the loop for (a) above after the "release to air =no", if
process change results in a release to air, it is not clear how the
loop is affected.
(c) there appears to be an endless loop at "Notify Affected
Persons.."
7. Comment (SPI) : The flow chart contains a box "EPA Approved
Analytical Method." The only way you can get out of the box is to
develop an approved method. Thus, the title should reflect what is
actually required to be done.
EPA Response: The flow chart was intended merely to provide a
simplified illustration, and not to substitute for the requirements
specified in the 5(e) consent order. However, to avoid confusion,
the flow chart has been deleted.
8. Comment (Labor): Medical Exams and Surveillance: A section on
medical exams and surveillance should be included:
a. To determine whether workers are medically capable of wearing
respirators.
b. Monitor any resulting health effects of exposure to a PMN
substance for which not much is known about its toxicological
properties. Exams could be designed based upon the toxicological
properties of other chemicals that have similar molecular
structures.
c. Will act as a check on the adequacy of PPE, including
respirators.
d. Will act as a check on the adequacy of the NCEL for a given PMN
substance.
The Medical Exam and Surveillance requirements must comply
with the Recordkeeping requirements of OSHA standards under 29 CFR
1910.20 as well.
EPA Response: 29 CFR 1910.134 requires a medical exam for
respirator selection and is required by reference in the '5(e)
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Order. However, EPA does not plan to address this issue at the
current time. Suggestions, comments or documents bearing on
medical exams and surveillance are, of course, welcomed by the
Agency. EPA is aware of OSHA's effort to establish generic medical
surveillance requirements, and EPA may revisit this issue when the
OSHA requirements are finalized.
9. Comment (Labor): Labeling should include physical (safety)
hazards under (i)(A).
MSDS should include (xiii), the NCEL AL and STEL specified by
EPA. In addition, the OSHA HAZCOM standard (1910.1200) language
regarding access to claimed confidential information by various
parties in both emergency and non-emergency situations should be
used.
Training under (2) (ii) should include physical hazards.
Subsection (g)(1) through (4) should be modified after OSHA's 20
CFR 1910.1200 appendix A and should include physical hazards.
EPA Response: EPA agrees that the MSDS should include the NCEL and
STEL, and has now included them in the Hazard Communication
requirements in the Consent Order. Although, EPA's New Chemicals
Program does not specifically address physical hazards, EPA
encourages companies, in keeping with the spirit of hazard
communication, to include warnings of physical hazards.
10. Comment (CMA): Do these sections imply that the selection of
protective equipment cannot be based on data from similar chemicals
but must be based solely on the new chemical? CMA believes that
relevant information on similar chemicals can be used to make
decisions about worker protection.
11. Comment (SPI): It appears that one cannot select protective
equipment based on analogous data to a similar chemical but must
test each PMN chemical separately. This could represent a
significant burden for a company and does not recognize well-
established practice.
EPA Response: As a general rule in the NCELs program, EPA expects
that selection of appropriate respiratory protection for the PMN
substance will be based on monitoring of the PMN substance itself.
On a case-by-case basis, EPA will consider, and has allowed, use
of analogue data for monitoring exposures to the PMN substance and
selecting appropriate personal protective equipment. To rely on
monitoring of an analogous substance, the company must adequately
demonstrate to EPA the validity of its proposed approach, for
example, that the quantitative ratio between the analogue substance
and the PMN substance will be constant, so that the analogue
substance provides an accurate measure of the PMN substance. EPA
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routinely accepts information provided by submitting companies in
its deliberations.
VII. NON-NCELs
1. Comment (AIHA): Greater reliance on industrial hygiene
professionals should be reflected in TSCA Section 5(e), not just in
the proposed NCEL section but in all aspects of worker protection.
Reference to industrial hygienists for worker protection and other
aspects under TSCA would improve compliance with worker protection
directives.
The worker protection and NCEL sections currently proposed,
under TSCA Section 5(e), were considered by some AIHA reviewers to
be confining and (depending on the situation) unnecessary. If the
professional judgment of industrial hygienists is relied upon, some
of the micromanaging detail that would cost both the agency and
industry time and effort could be avoided.
AIHA suggests that beginning on the bottom of Page 8,
Protection in the Workplace under TSCA Section 5(e), EPA should
include reference to industrial hygienists to allow changes to be
made in the worker protection plan as appropriate. This
modification will allow necessary flexibility to be exercised
professionally by industrial hygienists for changing workplace
protective measures with no compromise to worker safety and health.
EPA Response: EPA recognizes the capabilities of the industrial
hygiene (IH) profession, and encourages all Industrial Hygienists
to participate actively in issues bearing on new chemical
substances, such as the NCELs program. The worker protection
requirements are based on existing OSHA and NIOSH requirements, as
well as good industrial hygiene practice, with the intent of
providing consistency for those facilities which must meet both EPA
and OSHA monitoring requirements. If changes to the consent order
requirements are necessary in an individual case, these can be
negotiated before the order is signed, or revised afterwards by
petitioning the Agency to modify the terms of the order. If OSHA
monitoring requirements are modified, EPA will reevaluate these
requirements, as appropriate.
2. Comment (ACTWU): Effectiveness of respirator program rules:
The respirator requirements are inadequate in that they do not
provide for mandatory monitoring of exposures. It is inconceivable
to us how an employer can design a truly protective respirator
program without having first characterized the extent of workers'
exposure.
There are other problems as well with the requirements for
this program. Prominent among these is the absence of any
consideration for the health effects of respirator use on the
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workers in question, especially on workers exposed to respiratory
toxins. In view of the failure of this program's requirements to
adequately complement the typical exposure monitoring and medical
surveillance rules in OSHA health standards, I suggest that you
reconsider the entire structure of the proposed Consent Decree. In
particular, I suggest that you gather detailed data from some or
all of 600 situations where EPA has already signed consent decrees
to determine the extent to which workers have suffered adverse
health effects. In doing so, you should involve NIOSH due to EPA's
inability to clinically evaluate the health status of active
workers.
EPA Response: EPA's respirator requirements in the Protection in
the Workplace section of the Order incorporate by reference the
OSHA respirator requirements under 29 CFR 1910.134. While 29 CFR
1910.134 does not explicitly require monitoring for respirator
selection, good industrial hygiene practice would dictate
development of an exposure assessment based at least on
consideration of relevant objective data, if not actual monitoring.
Medical surveillance requirements are also contained in 1910.134.
More importantly, the above comment directly underscores much
of EPA's underlying rationale for developing the NCELs program.
EPA is fully aware of the potential problems associated with
respirator use and is proposing the NCEL approach as an alternative
to respirator use. Source reduction, engineering and
administrative controls are preferred by EPA to the use of
respirators.
The suggestion about collecting data on adverse effects to
workers from substances regulated by '5(e) Orders is a good one.
However, most data of this type should be reported pursuant to
'8(e) of TSCA. Although current resource constraints prevent the
Agency from being able to do more at this time, EPA may consider
such a study in the future.
3. Comment (Labor): Protection in the Workplace Section: The
a(l) references to 29 CFR 1910.132 and 1910.133 as PPE selection
and use requirements would be usefully improved if 29 CFR
1910.120(g) and appendix D were added. 1910.120 addresses PPE
requirements, particularly where exposures may be unknown, in far
better fashion than does 1910.132 and 133. Further, 1910.120 is
often not familiar to most employers so reference therefore would
highlight this superior approach to PPE.
Subsection a (4) might usefully reference the Revised NIOSH
Respirator Decision Logic (NIOSH Publication No. 87-108, May 8,
1987) as one basis for the required respiratory protection program.
In addition, a (4) might be revised to state that the NIOSH RDL
serves as the basis for respiratory selection. 30 CFR 11 serves as
the basis for respirator certification and that only respirators
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certified pursuant thereto may be utilized, and that 29 CFR
1910.134 serves as the minimum requirements for respirator use. It
is useful to note that 1910.134 requires a medical exam per our
suggestions for a medical exam and surveillance program.
EPA Response: OSHA has revised the personal protective equipment
(PPE) requirements for face, head, eye and foot protection to
reflect improved developments and allow the use of better personal
protective equipment. These improved requirements are incorporated
by reference in the NCELs provisions of the '5(e) Consent Order.
However, the requirements of 1910.120 address PPE selection for
hazardous waste and emergency response which are inappropriate for
many industrial operations regulated by TSCA '5. EPA requirements
are consistent with comparable OSHA requirements. EPA may impose
additional requirements for upfront glove permeation testing or
other requirements in cases where EPA is especially concerned about
dermal exposure to a particular PMN substance.
4. Comment (CMA): Does EPA have a mechanism for updating the 5(e)
order if the specific ASTM methods cited on page 10 of the draft
are revised or superseded? CMA suggests that a statement be
provided in this section that refers to the use of "the best
available method."
EPA Response: EPA has mechanisms for updating the 5(e) Order
requirements as the ASTM methods are revised and superseded. Where
there is a recommended method, EPA would prefer to use the most
current and recommended method for PMNs, and to keep abreast of
these changes.
5. Comment (SOCMA): Regarding page (vi) of the preamble of the
draft Section 5(e) Order, EPA should explain how it plans to
estimate dermal exposure and inhalation exposure for the purpose of
establishing NCELs.
EPA Response: Methods for estimating occupational dermal and
inhalation exposure are explained in the Chemical Engineering
Branch (CEB) Manual used by EPA/OPPT's CEB. The CEB Engineering
Manual has been provided to many industry contacts and is available
from CEB upon request. It is unnecessary to include this level of
detail in the preamble of each consent order. To request a copy,
please call the CEB at (202) 260-1664.
6. Comment (NIOSH): Several reviewers were concerned that
potential toxic effects from dermal exposures were not adequately
addressed. The exemption for solutions of less than 1%
concentration may not be appropriate for toxic substances with low
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saturation concentrations [Brown et al. 1984; Kissel and McAvoy
1989].
EPA Response: The standard 1%/0.1% de minimis exemption provision
is deleted by EPA in cases where it is inappropriate. Cases are
individually analyzed to ensure that all the provisions in the
Order are tailored to the specific chemical substance under review.
7. Comment (Labor): Acute Illness: EPA should require that any
acute illness suffered by a worker caused or potentially caused by
the "new chemical" be documented and reported to EPA.
EPA Response: If the "new" chemical is implicated as the cause of
serious adverse effects such as those listed in Part V(a) of EPA's
March 16, 1978 TSCA Section 8(e) Policy Statement ("Statement of
Interpretation and Enforcement Policy; Notification of Substantial
Risk"; 43 FR 11110, March 16, 1978, as amended at 52 FR 20083, May
29, 1987), such information must be reported immediately to EPA
under Section 8(e) of TSCA. Further information regarding Section
8(e) reporting can be obtained from EPA's TSCA Hotline at (202)
554-1404.
8. Comment (Labor): New Chemical Ingestion: The oral exposure
route is essentially ignored. It should not be. Requirements
addressing prevention of oral exposure, where appropriate to the
specific new chemical, should be included in the "Order."
EPA Response: EPA does consider potential hazards from ingestion
due to oral exposure. There are no specific requirements for
preventing oral exposure as many work places using new chemicals
are also regulated by OSHA and would be subject to existing OSHA
Standards which address prevention of oral exposure. Specifically,
29 CFR 1910.141, which applies to "permanent places of employment",
requires that no employee is to consume food or beverage in any
area exposed to a toxic material. In addition, this section
imposes other general environmental controls. To the extent that
these OSHA provisions apply to any signatory of the '5(e) Order,
additional constraints are not necessary to prevent oral exposure
to the new chemical substance.
9. Comment (SPI): Page 38 - It is confusing what specifically is
covered by HAZcom and what is not. The NCEL requirements appear to
be over and above HAZcom requirements and need to be clearly
defined. Clarification is also needed as to how changes in HAZcom
will affect NCEL requirements. There does not seem to be any
relief here for future HAZcom actions that may duplicate or replace
the EPA mandated actions.
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EPA Response: The NCELs and Hazard Communication requirements are
very different in nature. EPA has essentially adopted the
provisions of OSHA's Hazard Communication Standard (29 CFR
1900.1200) in '5(e) Consent Orders where the PMN substance may
present an unreasonable risk of injury to human health. These
provisions govern the manner in which the hazards which are related
to the PMN substance are to be communicated to persons reasonably
likely to be exposed to the PMN substance. The NCELs provisions
provide companies with an alternative to respirator protection only
and do not preempt the provisions of the Hazard Communication
Program section of the order. The provisions in the Hazard
Communication section do not address respirator use, and would
therefore not pose any conflicts with the NCELs provisions.
10. Comment (SPI) : Page 42- All chemicals do not have both
chemical and common names.
Page 17- Human health hazard statements do not address
possible eye effects.
EPA Response: All chemicals have chemical names. If a chemical
has no common name, none would be required. Eye effects are
relatively uncommon. However, if EPA has a concern that a
particular substance may cause eye effects, EPA would add such a
statement in the individual '5(e) Order for that chemical
substance.
Attachments:
I. Description of EPA's NCELs Standard Setting Methodology
II. List of References
III. EPA's Aug. 6, 1991 Draft of NCELs TSCA '5(e) Order
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ATTACHMENT I
EPA'S METHODOLOGY FOR
DETERMINING AN APPROPRIATE NEW CHEMICAL EXPOSURE LIMIT
UNDER '5(e) OF THE TOXIC SUBSTANCES CONTROL ACT
There are usually no direct toxicity data on a new chemical on
which to base an exposure limit. However, EPA may determine that
toxicity data on one or more structurally analogous existing
chemicals supports a finding that a new chemical may present an
unreasonable risk of injury via inhalation exposure. Because such
analogue may provide relevant information about the potential
toxicity of a new chemical, analogue data may be useful for
determining an appropriate exposure limit whenever (1) there is a
defined endpoint such as a no observed adverse effect level
(NOAEL), and (2) EPA is reasonably confident that the new chemical
is not significantly more toxic than its analogue. The following is
a brief discussion on how EPA generally uses analogue data (much as
EPA would use direct data on the PMN substance itself) to set
exposure limits in the New Chemicals Program.
1. Non-Cancer Effects
In a typical case in which analogue data would be used to set
an exposure limit, the test endpoint such as the NOAEL or, less
commonly, the LOAEL (lowest observed adverse effect level) in units
of milligrams of chemical per kilogram of body weight per day
(mg/kg/day) is divided by an appropriate uncertainty factor, the
magnitude of which will depend on the type of study and its
duration. The uncertainty factor is a product of several smaller
uncertainty factors such as a factor for individual variability
within exposed human populations and a factor to allow for greater
human sensitivity to a chemical in comparison to a test species.
The quotient, also expressed in units of mg/kg/day, may be
considered a permissible daily dose, that is, a dose at which an
adult human would be unlikely to suffer adverse effects if exposed
for a working lifetime. The permissible daily dose is multiplied
by the weight of an average adult (70 kg) to convert the dose to
the daily amount or mass absorbed per person (in units of mg/day).
(If appropriate, this number may adjusted to account for less than
100% absorption.) The numerical value for the exposure limit in
units of mg per cubic meter (mg/m3) is obtained by dividing the
daily amount in units of mg/day by 10 m3, the volume of air inhaled
in a typical eight hour work shift.
For example, if concern for a new chemical is based on data
for an analogue indicating that it may be a developmental toxicant,
then a limit for inhalation exposure could be set for the new
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chemical using the analogue data. Assume that the NOAEL for
developmental toxicity in an animal study was 100 mg/kg/day. The
permissible daily human dose is 1 mg/kg/day obtained by dividing
the NOAEL by 100, the uncertainty factor typically used for a
developmental toxicity study with a NOAEL. The permissible amount
absorbed per person per day is 70 mg, obtained by multiplying the
permissible human dose by 70 kg. The inhalation exposure limit is
7 mg/m3, obtained by dividing the permissible amount absorbed by 10
m3. (Again, if appropriate, this number may adjusted to account
for less than 100% absorption.)
2. Carcinogens
For non-cancer effects, the likelihood of observing adverse
effects in test animals (and presumably man) is primarily dependent
upon the daily dose in units of mg of toxicant per kilogram of body
weight per day. For cancer, however, the probability of observing
tumors is thought to be primarily a function of cumulative dose in
terms of mg of carcinogen per kilogram of body weight per lifetime.
This difference has an important bearing on the way a health-based
exposure limit is derived for a carcinogen versus a non-carcinogen.
In regulating new chemicals that are potential carcinogens,
OPPT risk managers have established a policy that a cancer risk of
10~4 or less is acceptable, that is, if exposure to a new chemical
causes no more than 1 case of cancer in a population of 10,000
exposed workers, then that is considered an acceptable risk. To
determine the maximum workplace exposure to a new chemical that
will result in acceptable risk, the acceptable risk level, e.g. 10~
4, is divided by the slope factor of an appropriate analogue. The
slope factor, a numerical measure of the activity of a carcinogen,
is based on dose-response data from animal tests, but is adjusted
to theoretically predict tumor response in man. The quotient,
termed the lifetime average daily dose (LADD), is the dose of new
chemical in units of milligrams of carcinogen per kilogram of body
weight per day (mg/kg/day) such that, if a person were exposed over
an entire lifetime, the probability of contracting cancer from
exposure to the new chemical would be 10~4. In fact, a worker is
not exposed to a new chemical over a lifetime, rather exposure
occurs over a 'work life' or a fraction of a work life. For risk
assessment purposes, we usually assume that a worker works a
maximum of 250 days out of a 365 day year, and a maximum of 40
years out of a 70 year lifespan. The LADD is therefore multiplied
by the ratios 365/250 and 70/40 to arrive at a "work life average
daily dose" in units of mg/kg/day. Beyond this point in the
derivation of the exposure limit, the mathematical operations are
identical to those discussed above for a non-cancer effect. The
adjusted average daily dose is multiplied by the weight of an
average adult worker (70 kg) and divided by 10 m3, the volume of
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air inhaled in an eight hour workday. The result of this
calculation is the inhalation limit in units of mg/m3. (Again, if
appropriate, this number may adjusted to account for less than 100%
absorption. )
For example, assume that a carcinogenic analogue of a new
chemical has a slope factor of 0.01 (mg/kg/day)-1. If the
acceptable risk level is 10~4 then the lifetime average daily dose
is 0.01 mg/kg/day (10~4 divided by 0.01 (mg/kg/day)-1 = 0.01
mg/kg/day. To adjust for actual working days in a lifetime, 0.01
mg/kg/day is multiplied by 365/250 and 70/40 which results in an
adjusted value of 0.026 mg/kg/day. Multiplication of the adjusted
value by 70 kg and division by 10 m3 results in an exposure limit
of 0.2 mg/m3. (Again, if appropriate, this number may adjusted to
account for less than 100% absorption.)
The level calculated in the example above is quite low, and
would be technically difficult to attain or to monitor. With weaker
carcinogens the value of the inhalation limit would be somewhat
higher, however, the slope factor chosen in the example is low,
i.e., most carcinogens tested are more active. Thus for new
chemicals which may be carcinogenic and which are manufactured,
processed, or used throughout the year or a large fraction of the
year, and have indefinite life spans, it may be difficult to attain
or monitor an airborne concentration that would result in a risk of
10~4 or less.
Feasibility-
Technological and economic feasibility of meeting an exposure
limit will be a key consideration in "safer substitute/relative
risk" cases where the company provides EPA with sufficient evidence
that a new chemical substance is a desirable replacement for a more
hazardous existing chemical. For such cases, EPA will strive to
set a NCEL for the new chemical at a level that not only protects
human health but also is feasible for the manufacturer. The Agency
is very interested in working with industry to achieve net risk
reduction.
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ATTACHMENT II
LIST OF REFERENCES
1. Development and Validation of Methods for Sampling and
Analysis of Workplace Toxic Substances, NIOSH, Research
Report, No. 80-133, 1980.
2. Eller, Peter M., editor, NIOSH Manual of Analytical Methods,
4th edition, 1990, U.S. Department of Health and Human
Services, Public Health Service, Centers for Disease Control,
NIOSH Division of Physical Sciences and Engineering,
Cincinnati, OH.
3. OSHA Technical Manual, OSHA Instruction CPL 2-2.20B, Feb. 5,
1990, U.S. Department of Labor, Directorate of Technical
Support, Office of Science and Technology Assessment,
Washington, D.C.
4. ACGIH Air Sampling Instruments, ISBN:0-936712-82-1, ACGIH
Publication Number 0029.
5. Clayton, George D., and Clayton, Florence M., editors, Patty's
1 Industrial Hygiene and Toxicology, Wiley Interscience
Publishing, Vols. 1A-1B, General Principles, 4th edition,
Vols. 2A-2C, Toxicology, 3rd revised edition, Vol. 3A, The
Work Environment, 2nd edition, Vol. 3B, Biological Response,
2nd edition.
6. Perez, C., and Soderholm, S. C., "Some Chemicals Requiring
Special Consideration When Deciding Whether to Sample the
Particle, Vapor, or both Phases of an Atmosphere," Applied
Occupational Environmental Hygiene, 6 (10) :859-864, October
1991.
7. Chaoling Yao, et. al. , "A Multipurpose Industrial Hygiene
Controlled Atmosphere Testing Chamber," Am. Ind. Hyg. Assoc.
J. (54) June 1993.
8. Test Methods for Evaluating Solid Waste, Office of Solid Waste
and Emergency Response, Washington, DC 20460, November 1986,
SW-8 4 6.
9. Compendium of Methods for the Determination of Toxic Organic
Compounds in Ambient Air, Atmospheric Research and Exposure
Assessment Laboratory, ORD, USEPA, EPA/600/4-89/017, June
1988 .
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ATTACHMENT III
AUGUST 1991 DRAFT
TSCA '5(e) NEW CHEMICAL EXPOSURE LIMIT PROVISIONS
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