1363). Because a substantial amount of cement in the U.S. is produced
in winter and stored for use during warmer weather, ferrous sulfate
added to the cement at the time of production could be oxidized during
that time, rendering it ineffective (Tr. 1363).
    Considering this evidence, OSHA does not believe the record
demonstrates that the addition of

ferrous sulfate to portland cement in the U.S. would necessarily result
in a reduction in the incidence of Cr(VI)-induced allergic contact
dermatitis. Therefore, OSHA does not believe that requiring the
addition of ferrous sulfate to cement is warranted.
    In any event, even if ferrous sulfate was completely effective in
eliminating the potential for Cr(VI)-induced allergic contact
dermatitis from portland cement, the potential for portland cement to
induce irritant contact dermatitis would not be affected. (See section
V(D) of this preamble for additional discussion.) Therefore,
appropriate protective clothing, good hygiene practices, and training
on hazards and control methods would still be necessary and these are
adequately covered by OSHA's generic standards.

Pesticides

    The final rule does not cover exposures to Cr(VI) that occur in the
application of pesticides. Some Cr(VI)-containing chemicals, such as
chromated copper arsenate (CCA) and acid copper chromate (ACC), are
used for wood treatment and are regulated by EPA as pesticides. Section
4(b)(1) of the OSH Act precludes OSHA from regulating working
conditions of employees where other Federal agencies exercise statutory
authority to prescribe or enforce standards or regulations affecting
occupational safety or health. Therefore, OSHA specifically excludes
those exposures to Cr(VI) resulting from the application of a pesticide
regulated by EPA from coverage under the final rule.
    The exception for exposures that occur in the application of
pesticides was limited to the proposed standard for general industry.
At the time, OSHA was not aware of exposures to Cr(VI) from application
of pesticides in other sectors. Exposures to Cr(VI) from pesticide
application outside of general industry were brought to OSHA's
attention during the public comment period (Exs. 39-47, p. 9; 39-48, p.
4; 39-52). This provision excluding coverage or exposures occurring in
the application of pesticides has therefore been added to the standards
for construction and shipyards as well.
    The exemption pertains to the application of pesticides only. The
manufacture of pesticides containing Cr(VI) is not considered pesticide
application, and is covered under the final rule. The use of wood
treated with pesticides containing Cr(VI) is also covered. In this
respect, the Cr(VI) standard differs from OSHA's Inorganic Arsenic
standard (29 CFR 1910.1018). The Inorganic Arsenic standard explicitly
exempts the use of wood treated with arsenic. When the Inorganic
Arsenic standard was issued in 1978, OSHA found that the evidence in
the record indicated ``the arsenic in the preserved wood is bound
tightly to the wood sugars, exhibits substantial chemical differences
from other pentavalent arsenicals after reaction, and appears not to
leach out in substantial amounts'' (43 FR 19584, 19613 (5/5/78)). Based
on the record in that rulemaking, OSHA did not consider it appropriate
to regulate the use of preserved wood. A number of commenters argued
that a similar exception should be included in the final rule for use
of wood preserved with Cr(VI) compounds (Exs. 38-208; 38-231; 38-244;
43-28). However, OSHA's exposure profile indicates that work with wood
treated with pesticides containing Cr(VI) can involve Cr(VI) exposures
above the new PEL (see FEA, Chapter III). OSHA therefore considers a
blanket exception from the scope of the final rule for use of wood
treated with Cr(VI) to be unjustified.

Other Requested Exemptions

    In addition to those who maintained that Cr(VI)-treated wood should
be exempted from the final rule, a number of commenters requested
exemptions from the final rule for other operations or industries
(e.g., welding, electric utilities, Cr(VI) pigment production,
residential construction, and telecommunications (Exs. 38-124; 38-203;
38-205; 38-211; 38-230; 38-244; 38-254; 39-14; 39-15; 39-47; 47-25; 47-
37). OSHA does not believe that the evidence in the record supports a
blanket exception from the final rule for these operations and
industries. In no case have commenters submitted data demonstrating
that the operations or industries for which an exception was requested
do not involve exposures to Cr(VI) that present significant risk to the
health of employees. Rather, the data presented in Chapter III of the
FEA indicate that exposures in these sectors can and do involve
exposures at levels that entail significant risk to workers, and may
exceed the new PEL. OSHA therefore has not included exceptions for
these operations or industries in the final rule.
    One commenter argued that the provisions of the standard, including
the new PEL, should apply only where Cr(VI) exposures occur on more
than 30 days per year (Ex. 38-233, pp. 43-44). However, exposures of 30
or fewer days per year may involve cumulative exposures associated with
significant risk of lung cancer. For example, if an employee was
exposed to 50 [mu]g/m3 Cr(VI) for 30 days during a year,
that employee s cumulative exposure for the year would exceed that of
an employee exposed at the new PEL of 5 [mu]g/m3 working
five days a week through the entire year. Therefore, OSHA does not
believe such an exemption is appropriate because it would deny workers
exposed to relatively high levels of Cr(VI) for 30 or fewer days per
year the protections afforded by the Cr(VI) rule. The Agency does
include exceptions from certain requirements of the rule for exposures
occurring on fewer than 30 days per year (e.g., with regard to
requirements for engineering controls and periodic medical
surveillance). However, these exceptions are related to the practical
aspects of implementing protective measures, and not to an absence of
risk for exposures occurring on fewer than 30 days per year.
    Other commenters suggested that materials or substances containing
trace amounts of Cr(VI) (e.g., less than 0.1% or 1%) be exempted from
the final rule (Exs. 38-203; 38-254; 39-19; 39-47; 39-48; 39-52; 39-54;
39-56). In particular, some utilities argued that fly ash produced by
the incineration of coal contains trace amounts of Cr(VI) that are so
low as to be insignificant, and that an exclusion from the final rule
for coal ash was warranted (Ex. 39-40). Edison Electric Institute
supported this argument by submitting sampling data and material safety
data sheets that indicated the Cr(VI) concentrations in ash by-products
of the coal combustion process (Exs. 47-25-1; 47-25-2; 47-25-3; 47-25-
4; 47-25-5; 47-25-6; 47-25-7).
    OSHA does not believe that it would be appropriate to establish a
threshold Cr(VI) concentration for coverage of substances under the
scope of this final rule. The evidence in the rulemaking record is not
sufficient to lead OSHA to conclude that the suggested concentration
thresholds would be protective of employee health. While OSHA has
recognized that the Cr(VI) content of portland cement is sufficiently
low to warrant an exception from the standard, a threshold
concentration of 0.1% for Cr(VI) would be more than 50-fold higher than
Cr(VI) levels typically found in portland cement (< 0.002%). See above
discussion of the extremely low Cr(VI) concentration in portland cement
(< 20 [mu]g/g).
    Although evidence submitted to the record indicates that Cr(VI)
levels in coal ash may be comparable to levels in portland cement, OSHA
does not believe that the evidence is sufficient to establish that all
coal ash from all

sources will necessarily have comparable Cr(VI) content.
    A threshold concentration is also not reasonable because many
operations where Cr(VI) exposures occur are the result of work with
materials that do not contain any Cr(VI). Welders, who represent nearly
half of the workers covered by this final rule, do not ordinarily work
with materials that contain Cr(VI). Rather, the high temperatures
created by welding oxidize chromium in steel to the hexavalent state.
An exception based on a specified Cr(VI) concentration could be
interpreted to exclude these workers from the scope of the standard.
This would be particularly inappropriate in view of the fact that data
in the record show that many welders have significant Cr(VI) exposures.
    OSHA does, however, appreciate the concerns of commenters regarding
situations where they believe exposures are minimal and represent very
little threat to the health of workers. The Agency believes that a
reasonable approach is to have an exception based on Cr(VI) exposure
level. OSHA is therefore including in the final rule an exception for
those circumstances where the employer has objective data demonstrating
that a material containing chromium or a specific process, operation,
or activity involving chromium cannot release dusts, fumes, or mists of
chromium (VI) in concentrations at or above 0.5 [mu]g/m3 as
an 8-hour TWA under any expected conditions of use.
    OSHA believes this approach is sensible because it provides an
exception for situations where airborne exposures are not likely to
present significant risk and thus allows employers to focus resources
on the exposures of greatest occupational health concern. The Agency
has added a definition for ``objective data'' (discussed with regard to
paragraph (b) of the final rule) to clarify what information and data
can be used to satisfy the obligation to demonstrate that Cr(VI)
exposures will be below 0.5 [mu]g/m3.
    Other standards which have included similar exceptions (e.g.,
Acryolitrile, 29 CFR 1019.1045; Ethylene Oxide, 29 CFR 1910.1047; 1,3-
Butadiene, 29 CFR 1910.1051) have generally relied upon the action
level as an exposure threshold. A threshold lower than the action level
has been selected for the Cr(VI) rule because OSHA believes this to be
more protective of worker health given the existing significant risk at
the action level. Although OSHA understands the difficulties of
developing objective data to demonstrate that exposures will be below a
given level, the Agency believes that the 0.5 [mu]g/m3
coverage threshold represents an exposure level where it is still
reasonably possible to develop objective data to take advantage of this
exception if Cr(VI) exposure levels are minimal. For instance,
variation in exposures even in well controlled workplaces requires that
typical exposures be below 0.25 [mu]g/m3 in order for an
employer to be reasonably sure that exposures will consistently be
below 0.5 [mu]g/m3 (see Exs. 46-79; 46-80; 46-81). Where
typical exposures are below 0.25 [mu]g/m3, an industry
survey might be used to show that exposures for a given operation would
be below 0.5 [mu]g/m3 under any expected conditions of use.
    When using the phrase ``any expected conditions of use'' OSHA is
referring to situations that can reasonably be foreseen. The criteria
are not intended to be so circumscribed that it is impossible to meet
them. OSHA acknowledges that a constellation of unforeseen
circumstances can occur that might lead to exposures above 0.5 [mu]g/
m3 even when the objective data demonstration has been
correctly made, but believes that such occurrences will be extremely
rare.
(b) Definitions
    ``Action level'' is defined as an airborne concentration of Cr(VI)
of 2.5 micrograms per cubic meter of air (2.5 [mu]g/m3)
calculated as an eight-hour time-weighted average (TWA). The action
level triggers requirements for exposure monitoring and medical
surveillance.
    Because employee exposures to airborne concentrations of Cr(VI) are
variable, workers may sometimes be exposed above the PEL even if
exposure samples (which are not conducted on a daily basis) are
generally below the PEL. Maintaining exposures below the action level
provides increased assurance that employees will not be exposed to
Cr(VI) at levels above the PEL on days when no exposure measurements
are made in the workplace. Periodic exposure measurements made when the
action level is exceeded provide the employer with a degree of
confidence in the results of the exposure monitoring. The importance of
the action level is explained in greater detail in the exposure
determination and medical surveillance discussions of this section
(paragraphs (d) and (k) respectively).
    As in other standards, the action level has been set at one-half of
the PEL. The Agency has had successful experience with an action level
of one-half the PEL in other standards, including those for inorganic
arsenic (29 CFR 1910.1018), ethylene oxide (29 CFR 1910.1047), benzene
(29 CFR 1910.1028), and methylene chloride (29 CFR 1910.1052).
    Following the publication of the proposed rule, which included a
proposed action level of 0.5 [mu]g/m3 (\1/2\ the proposed
PEL of 1 [mu]g/m3), OSHA received several comments
pertaining to the definition of the action level. Commenters such as
the International Brotherhood of Teamsters (IBT) supported OSHA s
preliminary determination that the action level should be set at one-
half the permissible exposure limit (Exs. 38-199-1, p. 9; 38-219, p.
16-17; 38-228-1; 40-10-2). The IBT stated that the action level set at
one-half the PEL has been successful historically in OSHA's standards
such as inorganic arsenic, cadmium, benzene, ethylene oxide,
methylenedianiline, and methylene chloride (Ex. 38-199-1, pp. 9, 44).
NIOSH also supported OSHA's approach, stating that the action level of
one-half the PEL is the appropriate level to indicate sufficient
probability that an employee's exposure does not exceed the PEL on
other days (Ex. 40-10-2, p. 17). The North American Insulation
Manufacturer's Association (NAIMA) agreed that an action level of one-
half the PEL is appropriate (in conjunction with a higher PEL than that
proposed) (Ex. 38-228-1, pp. 23-24).
    Previous standards have recognized a statistical basis for using an
action level of one-half the PEL (see, e.g., acrylonitrile, 29 CFR
1910.1045; ethylene oxide, 29 CFR 1910.1047). In brief, OSHA previously
determined (based in part on research conducted by Leidel et al.) that
where exposure measurements are above one-half the PEL, the employer
cannot be reasonably confident that the employee is not exposed above
the PEL on days when no measurements are taken (Ex. 46-80).
    Following the publication of the proposed rule, the United
Automobile, Aerospace, and Agricultural Implement Workers of America
(UAW) requested an action level of one-tenth of the permissible
exposure limit (PEL) (Tr. 791; Exs. 39-73; 39-73-2, pp. 3, 10; 40-19-
1). The UAW argued that the lower action level is appropriate because
variability in exposures is greater than was previously believed in
some occupational settings. While OSHA previously assumed a geometric
standard deviation (GSD) of 1.4, the UAW stated that a GSD of 2 should
be assumed as a matter of policy. They concluded that this GSD implies
an action level of one-tenth the PEL to minimize the frequency of
exposures above the PEL on days when measurements are not taken (Ex.
39-73-2, p. 12).

    If the variability of workplace exposures is typically as high as
the UAW suggests, an action level less than one-half the PEL would be
required to give employers a high degree of confidence that employees'
exposures are below the PEL on most workdays. Leidel et al., calculated
that for exposures with a GSD of 2.0, an action level of 0.115 times
the PEL would be required to limit to 5% the probability that 5% or
more of an employee's unmeasured daily exposure averages will exceed
the PEL (Ex. 46-80, p. 29). However, the evidence in the record is
insufficient to permit OSHA to conclude that a GSD of 2.0 is typical of
workplace Cr(VI) exposures. Furthermore, while OSHA recognizes the
value of high (95%) confidence that exposures exceed the PEL very
infrequently (<  5%), the Agency believes that the action level should
be set at a value that effectively encourages employers to reduce
exposures below the action level while still providing reasonable
(though possibly <  95%) assurance that workers' exposures are typically
below the PEL. OSHA's experience with past rules and the comments and
testimony of NIOSH and other union representatives indicate that
reasonable assurance of day-to-day compliance with the PEL is achieved
with an action level of one-half the PEL (Exs. 40-10-2, p. 17; 199-1,
pp. 9, 44).
    The Agency's experience with previous standards also indicates that
an action limit of one-half the PEL effectively encourages employers,
where feasible, to reduce exposures below the action level to avoid the
added costs of required compliance with provisions triggered by the
action level. Where there is continuing significant risk at the PEL,
the decision in the Asbestos case (Building and Construction Trades
Department, AFL-CIO v. Brock, 838 F. 2d 1258 (D.C. Cir 1988)) indicates
that OSHA should use its legal authority to impose additional
requirements on employers to further reduce risk when those
requirements will result in a greater than de minimus incremental
benefit to workers' health. OSHA believes that the action level will
result in a very real and necessary further reduction in risk beyond
that provided by the PEL alone.
    The action level improves employee protection while increasing the
cost-effectiveness and performance orientation of the standard. The
action level will encourage employers who can, in a cost-effective
manner, identify approaches or innovative methods to reduce their
employees' exposures to levels below the action level, because this
will eliminate the costs associated with exposure monitoring and
medical surveillance. The employees of such employers will have greater
protection against adverse health effects because their exposures to
Cr(VI) will be less than half of those permitted by the permissible
exposure limit. Employees of those employers who are not able to lower
exposures below the action level will have the additional protection
provided by medical surveillance, exposure monitoring, and the other
provisions of the standard that are triggered by the action level.
    ``Chromium (VI) [hexavalent chromium or Cr(VI)]'' means chromium
with a valence of positive six, in any form or chemical compound in
which it occurs. This term includes Cr(VI) in all states of matter, in
any solution or other mixture, even if encapsulated by another or
several other substances. The term also includes Cr(VI) when created by
an industrial process, such as when welding of stainless steel
generates Cr(VI) fume.
    For regulatory purposes, OSHA is treating Cr(VI) generically,
instead of addressing specific compounds individually. This is based on
OSHA's determination that the toxicological effect on the human body is
similar from Cr(VI) in any of the substances covered under the scope of
this standard, regardless of the form or compound in which it occurs.
As discussed in Section V of this preamble, some variation in potency
may result due to differences in the solubility of compounds. Other
factors, such as encapsulation, may have some effect on the
bioavailability of Cr(VI). However, OSHA believes that these factors do
not result in differences that merit separate provisions for different
Cr(VI) compounds. OSHA considers it appropriate to apply the
requirements of the standard uniformly to all Cr(VI) compounds.
    ``Emergency'' means any occurrence that results, or is likely to
result, in an uncontrolled release of Cr(VI), such as, but not limited
to, equipment failure, rupture of containers, or failure of control
equipment. To constitute an emergency, the exposure to Cr(VI) must be
unexpected and significant. If an incidental release of chromium (VI)
can be controlled at the time of release by employees in the immediate
release area, or by maintenance personnel, it is not an emergency.
Similarly, if an incidental release of Cr(VI) may be safely cleaned up
by employees at the time of release, it is not considered to be an
emergency situation for the purposes of this section. Those instances
that constitute an emergency trigger certain requirements in this
standard (e.g., medical surveillance) that are discussed later in this
section.
    In comments submitted to OSHA following the publication of the
proposed Cr(VI) rule, the International Brotherhood of Teamsters (IBT)
disagreed with OSHA's definition of ``emergency''. IBT stated that all
spills and leaks involving Cr(VI) are unexpected and significant, and
should be considered emergencies (Ex. 38-199-1, pp. 20-21).
    OSHA does not agree with the IBT's position that every spill or
leak should be considered an emergency. Not all spills and leaks are
significant; the particular circumstances of the release, such as the
quantity involved, confined space considerations, and the adequacy of
ventilation will have an impact on the amount of Cr(VI) to which
employees are exposed when a spill or leak occurs. For example, a minor
spill that can be quickly cleaned up by an employee with minimal
airborne or dermal exposure to Cr(VI) is clearly not an emergency. In
addition, factors such as the personal protective equipment available,
pre-established standard operating procedures for responding to
releases, and engineering controls that employees can activate to
assist them in controlling and stopping the release are all factors
that must be considered in determining whether a release is incidental
or an emergency.
    The IBT also stated that the person who determines whether a spill
or leak constitutes an emergency situation should be qualified with
specific training, knowledge, and experience regarding the hazards
associated with exposure to Cr(VI) and the appropriate response
measures that must be implemented to prevent Cr(VI) exposures during
the spill or leak remediation (Ex. 38-199-1, pp. 20-21). OSHA believes
that the provisions of the Hazard Communication standard adequately
address the IBT's concern (29 CFR 1910.1200). Paragraph (h)(3) of that
standard directs employers to provide employees who are exposed or
potentially exposed to a hazardous chemical (such as Cr(VI)) with
training on the physical and health hazards of the chemical and

[t]he measures employees can take to protect themselves from these
hazards, including specific procedures the employer has implemented
to protect employees from exposure to hazardous chemicals, such as
appropriate work practices, emergency procedures, and personal
protective equipment to be used * * * (29 CFR 1910.1200
(h)(3)(iii)).

The Agency expects that employers and employees equipped with the
training required by the Hazard Communication

standard will be sufficiently knowledgable to determine whether an
emergency has occurred, and that it is not necessary to mandate
additional specialized training for this purpose.
    ``Employee exposure'' means exposure to airborne Cr(VI) that would
occur if the employee were not using a respirator. This definition is
included to clarify the fact that employee exposure is measured outside
any respiratory protection worn. It is consistent with OSHA's previous
use of the term in other standards.
    ``Historical monitoring data'' means data from chromium (VI)
monitoring conducted prior to May 30, 2006, obtained during work
operations conducted under workplace conditions closely resembling the
processes, types of material, control methods, work practices, and
environmental conditions in the employer's current operations. To
demonstrate employees' exposures, historical monitoring data must
satisfy all exposure monitoring requirements of this section (e.g.,
accuracy and confidence requirements).
    ``Objective data'' means information other than employee monitoring
that demonstrates the expected employee exposure to chromium (VI)
associated with a particular product or material or a specific process,
operation, or activity. Types of information that may serve as
objective data include, but are not limited to, air monitoring data
from industry-wide surveys; data collected by a trade association from
its members; or calculations based on the composition or chemical and
physical properties of a material.
    ``Physician or other licensed health care professional'' [PLHCP] is
an individual whose legally permitted scope of practice (i.e., license,
registration, or certification) allows him or her to independently
provide or be delegated the responsibility to provide some or all of
the particular health care services required by the medical
surveillance provisions of this final rule. This definition is
consistent with several recent OSHA standards, including the
respiratory protection standard (29 CFR 1910.134), the bloodborne
pathogens standard (29 CFR 1910.1030), and the methylene chloride
standard (29 CFR 1910.1052). In these standards, the Agency determined
that any professional licensed by state law to do so may perform the
medical evaluation procedures required by the standard. OSHA recognizes
that the personnel qualified to provide the required medical evaluation
may vary from state to state, depending on state licensing laws.
    At the public hearing, the 3M Company (3M) expressed concern with
OSHA's interpretation of licensing requirements for PLHCPs. In the
recent standards discussed above, OSHA has interpreted the requirements
to mean that PLHCPs must be licensed in the states of residence for the
employees they evaluate. This interpretation is based on OSHA's
recognition of state licensing laws that require PHLCP's to be licensed
in the state in which they practice. 3M encouraged OSHA to adopt an
expanded definition of PLHCP for the Cr(VI) standard, allowing PLHCPs
licensed in any U.S. state to evaluate employees residing in that or
any other state, arguing that other federal agencies such as the
Department of Transportation permitted similar allowances. 3M argued
that this arrangement `` * * * would permit one medical director to
oversee the program in several states'' where a company has operations
(Tr. 1592, Ex. 47-36). Moreover, 3M added that OSHA has no authority to
enforce state licensing requirements.
    Despite the concerns raised by 3M, OSHA continues to believe that
it is appropriate to establish PLHCP requirements consistent with state
requirements for medical practice. OSHA's goal is that the medical
surveillance provisions of the final Cr(VI) rule be conducted by or
under the supervision of a health care professional who is
appropriately licensed to perform those provisions and is therefore
operating under his or her legal scope of practice. OSHA also continues
to believe that issues regarding a PLCHP's legal scope of practice
reside most appropriately with state licensing boards. While OSHA does
not enforce state licensing requirements (e.g., fining an individual
PHCLP for operating outside their legal state license), OSHA can cite,
using the Cr(VI) standard, an employer for using a health care
professional who is not operating under his or her legal scope of
practice. Thus, the Agency believes that the proposed definition for
PHLCP is reasonable, and has retained it in the final rule. OSHA's
experience with other standards using this definition supports the
Agency's determination in this matter.
    ``Regulated area'' means an area, demarcated by the employer, where
an employee's exposure to airborne concentrations of Cr(VI) exceeds, or
can reasonably be expected to exceed the PEL. This definition is
consistent with the use of the term in other standards, including those
for cadmium (29 CFR 1910.1027), butadiene (29 CFR 1910.1051), and
methylene chloride (29 CFR 1910.1052).
    OSHA has not included a requirement for regulated areas in
construction and shipyards. This definition is therefore not included
in the standards for construction and shipyards.
    The definitions for ``Assistant Secretary'', ``Director'', ``High-
efficiency particulate air [HEPA] filter'', and ``This section'' are
consistent with OSHA's previous use of these terms found in other
health standards.
(c) Permissible Exposure Limit (PEL)
Introduction
    Paragraph (c) of the final rule establishes an 8-hour time-weighted
average (TWA) exposure limit of 5 micrograms of Cr(VI) per cubic meter
of air (5 [mu]g/m3). This limit means that over the course
of any 8-hour work shift, the average exposure to Cr(VI) cannot exceed
5 [mu]g/m3. The new limit applies to Cr(VI), as opposed to
the previous PEL which was measured as CrO3. The previous
PEL of 1 milligram per 10 cubic meters of air (1 mg/10m3, or
100 [mu]g/m3) reported as CrO3 is equivalent to a
limit of 52 [mu]g/m3 as Cr(VI).
    OSHA proposed a PEL of 1 [mu]g/m\3\ for Cr(VI). This PEL was
proposed because the Agency made a preliminary determination that
occupational exposure to Cr(VI) at the previous PEL resulted in a
significant risk of lung cancer among exposed workers, and compliance
with the proposed PEL was expected to substantially reduce that risk.
Based on the information available to OSHA at the time, a PEL of 1
[mu]g/m\3\ was believed to be economically and technologically feasible
for affected industries.
    The PEL was a focus of comment in the rulemaking process, revealing
sharply divided opinion on the justification for a PEL of 1 [mu]g/m\3\.
Some support was expressed for the proposed PEL (Exs. 38-199-1, p. 42;
38-219-1, p. 2; 39-73-1). The vast majority of commenters, however, did
not believe the proposed PEL was appropriate. Some maintained that a
higher PEL was warranted, arguing that the proposed limit was
infeasible or was not justified by the health and risk evidence (e.g.,
Exs. 38-205; 38-215; 38-231; 38-228; 38-233). Several commenters
suggested alternative PELs that they considered appropriate, such as 10
[mu]g/m\3\ (Exs. 38-134; 38-135; 38-195; 38-203; 38-212; 38-250; 38-
254), 20 [mu]g/m\3\ (Ex. 38-204), 23 [mu]g/m\3\ (e.g., Exs. 38-7; 43-
22; 43-23; 43-25; 43-39), or 26 [mu]g/m\3\ (Ex. 38-263). Others
maintained that the remaining risk at the proposed PEL was excessive
and believed OSHA should adopt a

lower PEL, suggesting 0.2 or 0.25 [mu]g/m\3\ (Exs. 39-71; 40-10-2; 47-
23; 47-28).
    After careful consideration of the evidence in the rulemaking
record, OSHA has established a final PEL of 5 [mu]g/m\3\. OSHA s
examination of the health effects evidence, discussed in section V of
this preamble, reaffirms the Agency's preliminary conclusion that
exposure to Cr(VI) causes lung cancer, as well as other serious adverse
health effects. OSHA's quantitative risk assessment, presented in
section VI, indicates that the most reliable lifetime estimate of risk
from exposure to Cr(VI) at the previous PEL is 101 to 351 excess lung
cancer deaths per 1000 workers. As discussed in section VII, this
clearly represents a significant risk of material impairment of health.
OSHA believes that lowering the PEL to 5 [mu]g/m\3\ will substantially
reduce this risk. OSHA estimates the lifetime excess risk of death from
lung cancer at the new PEL to be between 10 and 45 per 1000 workers.
    The Agency considers the level of risk remaining at the new PEL to
be significant. However, based on evidence evaluated during the
rulemaking process, OSHA has concluded that a uniform PEL of 5 [mu]g/
m\3\ is appropriate. The new PEL is technologically and economically
feasible for all industry sectors. In only two operations within one of
those sectors, the painting of aircraft and large aircraft parts in the
aerospace industry, is a PEL of 5 [mu]g/m\3\ infeasible. In accordance
with section 6(b)(5) of the OSH Act, OSHA has determined that the new
PEL is the lowest limit that employers can generally achieve,
consistent with feasibility constraints. Additional requirements are
included in the final rule to further reduce any remaining risk. OSHA
anticipates that these ancillary provisions will reduce the risk beyond
the reduction that will be achieved by the new PEL alone.
    OSHA's rationale for adopting a uniform PEL of 5 [mu]g/m\3\ is set
forth in greater detail below. The discussion is organized around the
issues of primary importance to commenters: (a) Whether a uniform PEL
is appropriate for all chromium compounds, (b) the technologic and
economic feasibility of various PELs, (c) the requirement of section
6(b)(5) to promulgate the most protective standard consistent with
feasibility, and (d) whether there is a need for a short-term exposure
limit.
A Uniform PEL Is Appropriate for All Chromium Compounds
    OSHA believes that it is appropriate to establish a single PEL that
applies to all Cr(VI) compounds. OSHA's preferred estimates of risk are
derived from two cohorts of chromate production workers that were
predominantly exposed to sodium chromate and sodium dichromate. A
number of commenters argued that risk estimates from these cohorts were
not applicable to certain other Cr(VI) compounds (Exs. 38-106; 38-201-
1; 38-205; 38-215-2).
    After carefully evaluating the epidemiological, animal and
mechanistic evidence in the rulemaking record, OSHA considers all
Cr(VI) compounds to be carcinogenic. (For additional discussion see
section V of this preamble.) OSHA has determined that the risk
estimates developed from the chromate production cohorts are reasonably
representative of the risks expected from equivalent exposures to
different Cr(VI) compounds in other industries. OSHA finds that the
risks estimated from the Gibb and Luippold cohorts of chrome production
workers adequately represent the risks to workers in other industries
who are exposed to equivalent levels of Cr(VI) compounds. (The
rationale supporting these conclusions is discussed in detail in
sections V and VI of this preamble. In particular, see Section VI(H) of
the Quantitative Risk Assessment.) Because OSHA's estimates of risk are
reasonably representative of all occupational Cr(VI) exposures, the
Agency considers it appropriate to establish a single PEL applicable to
all Cr(VI) compounds. A number of rulemaking participants supported
this approach (Exs. 38-214; 38-220; 39-20; 39-60; 40-10; 40-19). See
also, e.g., Color Pigments Mfr. Ass'n, Inc. v. OSHA, 16 F.3d 1157, 1161
(11th Cir. 1994):

    Given the absence of definiteness on the issue, the volume of
evidence that points at least implicitly to the dangers of cadmium
pigments, and the serious potential health risks present if cadmium
exposure is as great in pigment form as in other compounds, we
believe that OSHA was justified in choosing to include cadmium
pigments in the PEL * * * ;

Asarco, Inc. v. OSHA, 746 F.2d 483, 495 (9th Cir. 1984) (permissible
for OSHA to ``use trivalent arsenic studies and conclusions to support
inclusion of pentavalent arsenic in the standard'').
The Final PEL of 5 [mu]g/m\3\ Is Technologically and Economically
Feasible for all Affected Industries; the Proposed PEL Is Not
    OSHA has concluded that a PEL of 5 [mu]g/m\3\ is economically and
technologically feasible for all the affected industries. OSHA has also
concluded, based on the comments and evidence submitted to the record,
that the proposed PEL of 1 [mu]g/m\3\ is not feasible in all
industries. OSHA's feasibility determinations are explained below.
    Technologic feasibility of the final PEL. In making its
determination of technological feasibility, OSHA relied upon guidance
provided by the courts that have reviewed previous standards. In
particular, the decision of the U.S. Court of Appeals for the District
of Columbia on OSHA's Lead standard (United Steelworkers of America v.
Marshall, 647 F.2d 1189 (D.C. Cir. 1981)) established a benchmark that
the Agency has relied on for evaluating technological feasibility. The
court explained that OSHA has ``great discretion * * * in determining
the feasibility of a chosen PEL.'' 647 F.2d at 1309. Both technological
and economic feasibility are ``to be tested industry-by-industry.'' 647
F.2d at 1301. In order to establish that a standard is technologically
feasible, ``OSHA must prove a reasonable possibility that the typical
firm will be able to develop and install engineering and work practice
controls that can meet the PEL in most of its operations.'' 647 F.2d at
1272. The court allowed that ``insufficient proof of technological
feasibility for a few isolated operations within an industry, or even
OSHA's concession that respirators will be necessary in a few such
operations, will not undermine'' OSHA's finding of technological
feasibility. Id.
    Applying this definition of feasibility, OSHA has evaluated each
affected industry and has concluded that a PEL of 5 [mu]g/m\3\ can be
achieved through engineering and work practice controls, with only
limited respirator use, in every industry. The primary evidentiary
support for this conclusion is the report of Shaw Environmental, Inc.,
discussed in depth in the Final Economic and Regulatory Flexibility
Analysis (FEA). Based on the data collected by Shaw, OSHA concludes
that engineering controls, such as local exhaust ventilation (LEV),
process control, and process modification or substitution can be used
to control exposures in most operations.
    OSHA recognizes that there are certain instances in which
supplemental respirator use will be required because engineering and
work practice controls are not always sufficient to reduce airborne
exposures below the PEL. Summary information regarding the extent of
respirator usage expected at various potential PELs is presented in
Table VIII-3 (see section VIII, summary of the FEA). Considering this
information together with other data and analysis presented in the FEA,
OSHA has concluded that a PEL of 5 [mu]g/

m\3\ is technologically feasible in all affected industry sectors and
in virtually all operations, with the limited exception of some
aerospace painting operations discussed more fully below. In only three
sectors would respirator use be required by more than 5% of exposed
employees. In two of these sectors, chromate pigment producers and
chromium dye producers, use of respirators will be intermittent. The
third sector, stainless steel welding, presents technological
challenges in certain operations. However, the new PEL can clearly be
achieved in most operations with engineering and work practice
controls.
    OSHA recognizes that for two distinct operations within the
aerospace industry, painting aircraft and painting large aircraft
parts, engineering and work practice controls cannot control exposures
below 25 [mu]g/m\3\ and respirators would be required for most
employees performing these operations. (See additional discussion of
aerospace painting below.) For that reason OSHA is adopting a provision
for those specific operations requiring employers to use engineering
and work practice controls to limit employee exposures to 25 [mu]g/
m\3\. Respiratory protection must then be used to achieve the PEL.
    OSHA did not set the PEL at 25 [mu]g/m\3\, a level achievable in
every operation in every industry with engineering and work practice
controls alone. That approach is inappropriate because it would leave
the vast majority of affected employees exposed to Cr(VI) levels above
those that could feasibly be achieved in most industries and
operations. As discussed above, the lower PEL of 5 [mu]g/m\3\ is
feasible within the meaning of the case law, although it will result in
limited use of respirators in some industries and significant
respirator use in two painting operations in the aerospace industry.
The two aerospace painting operations with significant respirator use
are covered by the provision discussed above. For those operations,
OSHA weighed the added protection provided by respirators against the
negative aspects of respiratory protection requirements, and decided
that the additional respirator use was acceptable.
    Technological feasibility of the proposed PEL. OSHA concludes that
the proposed PEL of 1 [mu]g/m\3\ is not technologically feasible for
all industries under the criteria in the D.C. Circuit's Lead decision.
The court's definition of technological feasibility recognizes that for
a standard based on a hierarchy of controls, a particular PEL is not
technologically feasible simply because it can be achieved through the
widespread use of respirators. 647 F.2d at 1272. This is consistent
with OSHA's long-held view that it is prudent to avoid requirements
that will result in extensive respirator use.
    In its post-hearing brief, Public Citizen argued that a PEL should
be considered technologically feasible if respirator use would be
necessary to achieve compliance in a significant number of operations
within an industry, or even if the PEL could only be achieved through
use of respirators alone (Ex. 47-23, pp. 12-15). That position is
inconsistent with the established test for feasibility for standards
based on the hierarchy of controls. Moreover, as discussed in the
preamble explanation of paragraph (f) on methods of compliance, use of
respirators in the workplace presents a number of independent safety
and health concerns. The vision of workers wearing respirators may be
diminished, and respirators can impair the ability of employees to
communicate with one another. Respirators can impose physiological
burdens on employees due to the weight of the respirator and increased
breathing resistance experienced during operation. The level of
physical work effort required, the use of protective clothing, and
environmental factors such as temperature extremes and high humidity
can interact with respirator use to increase the physiological strain
on employees. Inability to cope with this strain as a result of medical
conditions such as cardiovascular and respiratory diseases, reduced
pulmonary function, neurological or musculoskeletal disorders, impaired
sensory function, or psychological conditions can place employees at
increased risk of illness, injury, and even death. Routine use of
respirators for extended periods of time is regarded by the Agency to
be of greater significance than intermittent use for short time
periods.
    OSHA also believes that respirators are inherently less reliable
than engineering and work practice controls. To consistently provide
adequate protection, respirators must be appropriately selected and
fitted, properly used, and properly maintained. Because these
conditions can be difficult to attain, and are subject to human error,
OSHA does not believe respirators provide the same degree of protection
as do engineering and work practice controls.
    Based on evidence and comment submitted in response to the
proposal, OSHA finds that a PEL of 1 [mu]g/m\3\ is not technologically
feasible for a substantial number of industries and operations
employing a large number of the workers covered by the standard. The
record shows that a PEL of 1 [mu]g/m\3\ is technologically infeasible
for welding and aerospace painting because engineering and work
practice controls cannot reduce exposures below 1 [mu]g/m\3\ for many
operations. OSHA also finds that the record contains insufficient
evidence to establish the technologic feasibility of the proposed PEL
for four other industries: chromate pigment producers, chromium
catalyst producers, chromium dye producers and some hard chrome
electroplaters. OSHA's findings on the technologic feasibility of the
proposed PEL are summarized below, and are discussed more extensively
in Chapter III of the FEA (in particular, see section titled:
``Technological Feasibility of the Proposed 1 [mu]g/m\3\ 8-Hour TWA
PEL.'').
    Welding. OSHA has concluded that a PEL of 1 [mu]g/m\3\ is not
technologically feasible for shielded metal arc welding (SMAW) on
stainless steel because engineering and work practice controls cannot
generally reduce employee exposures to below 1 [mu]g/m\3\. Almost one
third (29%) of all stainless steel SMAW operations would need to use
respirators at a PEL of 1 [mu]g/m\3\. In general industry alone, more
than half (52%) of stainless steel SMAW processes would be unable to
use engineering or work practice controls to reduce Cr(VI) exposures
below 1 [mu]g/m\3\. Notably, stainless steel welding is widespread
throughout the economy; it occurs in over 20,000 establishments
employing approximately 127,000 workers in over sixty-five 3-digit
NAICS codes. SMAW is the most common type of stainless steel welding
and is performed by more than 67,000 employees--more than half of the
total number of stainless steel welders and one quarter of all welders
covered by the standard.
    OSHA initially recommended the substitution of gas metal arc
welding (GMAW) for SMAW as the cheapest and most effective method to
reduce Cr(VI) exposures. GMAW, like SMAW, is a common type of welding,
but GMAW tends to produce lower exposures than SMAW. However, based on
hearing testimony and evidence submitted to the record, OSHA now
believes that only 60% of SMAW operations can switch to GMAW (Exs. 38-
220-1, p. 8; 39-60, p. 3; 39-70, p. 2; 35-410, p. 4). Moreover, even
among the SMAW operations with current exposures above 1 [mu]g/m\3\
that can switch to GMAW, only a portion (40% in general industry and
59% in construction and maritime)

would be able to achieve a PEL of 1 [mu]g/m\3\ without respirators.
    OSHA has also determined that a PEL of 1 [mu]g/m\3\ is
technologically infeasible for stainless steel welding that is
performed in confined or enclosed spaces due to limitations on the
availability of ventilation. Because engineering and work practice
controls cannot consistently reduce exposures to below 1 [mu]g/m\3\, a
large percentage of stainless steel welding operations in confined or
enclosed spaces would require respirators at a PEL of 1 [mu]g/m\3\. In
general industry, for example, 60% of welding tasks done on stainless
steel in confined spaces would be unable to comply with the proposed
PEL by using engineering or work practice controls.
    In sum, OSHA has concluded that it is infeasible for some of the
most common welding operations to achieve a PEL of 1 [mu]g/m\3\. For a
more detailed explanation of OSHA's technological feasibility analysis
for welding operations, see Chapter III of the FEA. OSHA has also
decided that although it may be feasible for some of the less common
types of welding operations to achieve a PEL of 1 [mu]g/m\3\ with
engineering and work practice controls, the ubiquitous nature of
welding necessitates a finding that a PEL of 1 [mu]g/m\3\ is generally
infeasible for all welding operations. In particular, OSHA believes
that the proposed PEL is infeasible for welding operations generally
because welding is not easily separated into high and low exposure
operations. Welders may perform different types of welding in the same
day, making it difficult or impossible for employers to monitor them on
an operation by operation basis. See, e.g., Ex. 39-22. In addition,
because workers doing different types of welding often work alongside
one another, what is technologically feasible for a welding operation
considered in isolation may not be technologically feasible for that
operation when it is performed next to SMAW on stainless steel or
another operation for which a PEL of 1 [mu]g/m\3\ is technologically
infeasible.
    Welding occurs in over 40,000 establishments spanning sixty-five
different 3-digit NAICS codes. Welding is done in a variety of sites
throughout many diverse workplaces (Ex. 38-8, p. 5). Stainless steel
SMAW is commonly done in close proximity to other welding or cutting
operations, which could expose nearby workers to the higher exposures
generated by the SMAW welder (Ex. 38-214, p. 7). The Specialty Steel
Industry of North America commented that, ``workers in job categories
other than those evaluated by OSHA may spend significant time in areas
of potential exposure'' (Ex. 38-233, p. 10). The Integrated Waste
Services Association similarly indicated that inspectors, scaffold
workers, laborers, pipe fitters, and refractory workers may pass
through areas with potential Cr(VI) exposure during nickel chrome alloy
overlay (Ex. 38-258, p. 2). The Building and Construction Trades
Department of the AFL-CIO also stated that ``workers may be exposed to
hazards even if they are not directly performing tasks associated with
Cr VI exposure via close proximity exposure'' (Ex. 31-6-1).
    Moreover, OSHA is aware that welders sometimes weld in many
different environments on a variety of types of base metal using
different welding methods in the course of a project or even during a
single work shift (Exs. 34-10, 38-235). In those situations, the
employee's overall exposure levels are inevitably influenced by the
variety of exposures present during the various welding tasks he or she
performs. Therefore, depending on how much time the employee spends
doing welding operations for which a PEL of 5 [mu]g/m\3\ is the lowest
feasible level, even the use of engineering and work practice controls
to comply with a PEL of 1 [mu]g/m\3\ in the other welding operations
would not necessarily reduce the employee's overall exposure levels
below that mark.
    Because of these factors, welding is not easily separated into high
and low exposure operations in the real work site. For these reasons,
OSHA believes the record demonstrates that the proposed PEL of 1 [mu]g/
m\3\ is infeasible for welding operations generally. Almost 270,000 of
the employees covered by the new standard engage in these welding
operations (Table VIII-2).
    Aerospace painting. There are approximately 8300 exposed employees
in aerospace painting (Table VIII-2). A PEL of 1 [mu]g/m\3\ is not
feasible for approximately two thirds of all aerospace painting
operations. At a PEL of 5 [mu]g/m\3\, only \1/3\ of aerospace painting
operations would require substantial respirator use.
    Exposures in aerospace painting are controlled by enclosing the
operations in painting booths or dedicated rooms with LEV. This is
feasible for small parts, but as the size of the parts increases it
becomes more difficult to control exposures. For example, when painting
most small parts, exposures below 1 [mu]g/m\3\ are achievable, but for
larger parts exposures can only be reduced to between 1 [mu]g/m\3\ and
5 [mu]g/m\3\ using engineering and work practice controls. This group
that can achieve levels between 1 [mu]g/m\3\ and 5 [mu]g/m\3\
(approximately \1/3\ of total aerospace painting operations) can use
LEV, but as the size of the part increases it becomes increasingly
difficult to provide good air flow around the entire part, such as
underneath large horizontal structures. Moreover, as the size of the
part increases, it becomes increasingly difficult for the painter to
position him or herself to avoid being downstream of the paint
overspray due to the geometry of the parts.
    When painting even larger parts, such as fuselages, wings or the
entire aircraft, exposures below 5 [mu]g/m\3\ are no longer achievable
without supplementary respiratory protection. Because these large parts
do not fit into enclosures or painting rooms, they must be painted in
oversized workspaces, typically hangers that can reach the size of a
football field (Ex. 38-106-2, p. 2). In oversized workspaces the
ventilation system becomes less effective and generally, the larger the
space, the more difficult it is to ventilate.
    Moreover, when ventilation is put into such areas, the simple
solution of increasing air flow is not feasible because the amount of
air that is needed to dilute or diffuse the contaminated air can
adversely affect the quality of the job to the point where the paint or
coating is unacceptable for its purpose of protecting the part or plane
(Ex. 38-106, p. 38). Thus, simply increasing the air flow in these
sites and situations is not a viable alternative. As discussed above,
OSHA has established a provision to address the situation where
exposures cannot be brought below 25 [mu]g/m\3\ through engineering and
work practice controls alone. However, a PEL of 5 [mu]g/m\3\ can be
achieved using respiratory protection for these operations.
    In short, OSHA believes a PEL of 5 [mu]g/m\3\ is feasible for
aerospace painting operations. Although one-third of those operations
will need to use respiratory protection to achieve the PEL, the
remainder can do so with engineering and work practice controls alone.
Half of that remaining group cannot achieve a PEL of 1 [mu]g/m\3\
because, even though they can take advantage of enclosures such as
paint rooms with LEV, the LEV becomes less effective as the part
becomes larger. For this reason lowering the PEL from 5 [mu]g/m\3\ to 1
[mu]g/m\3\ would result in the above-described substantial increase in
the number of employees required to wear respirators. OSHA has
therefore concluded that a PEL of 1 is not generally feasible for
aerospace painting. For a more detailed explanation of OSHA's
technological feasibility analysis for aerospace

painting operations, see Chapter III of the FEA.
    Other industries. There are other major industries or applications
where OSHA is confident the PEL of 5 [mu]g/m\3\ can be met with
engineering and work practice controls, but the record does not
establish that a PEL of 1 [mu]g/m\3\ would be technologically feasible.
In particular, chromate pigment producers, chromium catalyst producers,
and chromium dye producers would have difficulty meeting the proposed
PEL. A significant portion of operations in these industries are
conducted in open and often large areas that are very dusty, making
exposures hard to control. Just as in aerospace painting above, the
primary control is to enclose the operation and then ventilate.
However, some of the operations cannot be enclosed because of the
physical configuration of the plant, especially in older facilities
(Ex. 47-3, p. 55). Moreover, because the medium containing the Cr(VI)
tends to be a fine powder, additional LEV in any worksite potentially
can result in significant and intolerable product loss. In other words,
the product could be drawn up through the ventilation system (Ex. 38-
12, pp. 12-14).
    Thus, depending in large part on the number of facilities that can
accommodate enclosures, these operations could potentially require
extensive respirator use in order to meet a PEL of 1 [mu]g/m\3\; at 1
[mu]g/m\3\, OSHA expects that 44% of employees in these three
industries would need to wear respirators on at least an intermittent
basis. This number could be even higher if there are a large number of
facilities that cannot enclose troublesome operations.
    To find the proposed PEL technologically feasible for an industry,
OSHA must ``prove a reasonable possibility'' that the typical firm can
meet it with engineering and work practice controls in most operations.
United Steelworkers, 647 F.2d at 1272. Table VIII-3 indicates that
intermittent respirator use would be required to reach the proposed PEL
of 1 [mu]g/m\3\ for chromate pigment producers, chromium catalyst
producers, and chromium dye producers. The extent of daily respirator
usage that would be required to meet the proposed PEL is not clear if
the recommended controls of enclosures and automation of the key
operations are not feasible for existing facilities, but could be
substantial depending upon the variables discussed above. On balance,
OSHA does not believe that the record establishes the likelihood that
the typical firm in these industries can meet the proposed PEL with
engineering and work practice controls. There are a total of
approximately 469 exposed employees in these three industries (Table
VIII-2). For a more detailed explanation of OSHA's technological
feasibility analysis for chromate pigment producers, chromium catalyst
producers, and chromium dye producers, see Chapter III of the FEA.
    Technological feasibility is also an issue for hard chrome
electroplating operations where fume suppressants cannot be used to
control Cr(VI) exposures because they would interfere with the product
specifications, making the resulting product unusable.
    In conclusion, OSHA has determined that while a PEL of 5 [mu]g/m\3\
is technologically feasible for all affected industries, the record
does not support the feasibility of the proposed PEL of 1 [mu]g/m\3\
for welding operations, aerospace painting, chromate pigment producers,
chromium catalyst producers, chromium dye producers, and some hard
chrome electroplating operations.
    Economic feasibility of the final and proposed PELs. OSHA has also
evaluated the economic feasibility of the proposed and final PELs. With
regard to economic feasibility, OSHA must ``provide a reasonable
assessment of the likely range of costs of its standard, and the likely
effects of those costs on the industry,'' so as to ``demonstrate a
reasonable likelihood that these costs will not threaten the existence
or competitive structure of an industry, even if it does portend
disaster for some marginal firms.'' AFL-CIO v. OSHA, 965 F.2d 982 (11th
Cir. 1992). OSHA believes that the final PEL of 5 [mu]g/m\3\ is
feasible for all affected industries. (For a more detailed discussion
of OSHA's economic feasibility analysis, see Chapter VIII, Summary of
the Final Economic Analysis and Regulatory Flexibility Analysis,
Sections D and E.) In the majority of industries, costs will be less
than 1% of revenues. For fewer than 10 of the approximately 250 NAICS
(North American Industry Classification System) categories affected by
the rule, costs are estimated to exceed 1% of revenues. OSHA has
concluded that all affected industries will be able to absorb these
costs without threatening their existence or competitive structure.
Accordingly, OSHA has concluded that the new standard is economically
feasible for all industries.
    By contrast, the proposed PEL of 1 [mu]g/m\3\ would not be
economically feasible for a significant industry-electroplating job
shops (NAICS 332813; electroplating, plating, polishing anodizing and
coloring services). Electroplating establishments can be broadly
classified into two categories: (1) Job shops and (2) captive shops,
with roughly half of establishments falling into each category. Job
shops perform electroplating services for others, while captive shops
provide plating services to the facility of which they are part.
    A PEL of 1 [mu]g/m\3\ would result in costs exceeding 2.7% of
revenues and 65% of profits for electroplating job shops. As explained
further in section VIII of this preamble, and in the FEA, OSHA does not
believe that options for reducing impacts (e.g., phase-ins or allowing
use of respirators) would significantly alleviate the burden of the
proposed PEL. OSHA is concerned that these costs could alter the
competitive structure of the industry. Approximately 33,400 workers are
employed in electroplating job shops.
    Summary of the technological and economic feasibility of the final
and proposed PELs. To summarize, OSHA concludes that the final PEL of 5
[mu]g/m\3\ is technologically and economically feasible for the
affected industries. On the other hand, the proposed PEL of 1 [mu]g/
m\3\ would be technologically or economically infeasible or is of
unproven feasibility in a large number of industries and operations
covered by the standard, including welding, aerospace painting,
chromate pigment production, chromium catalyst production, chromium dye
production, some hard chrome electroplating operations, and
electroplating job shops. These operations affect approximately 312,170
exposed employees, or almost 56% of the total number of employees
occupationally exposed to Cr(VI) (Table VIII-2). This figure includes
270,000 employees in welding, 8,300 employees in aerospace painting
operations, 33,400 employees in electroplating job shops, and 469
employees in the other three industries. (Note that this number does
not include a separate count for employees performing hard chrome
electroplating in order to avoid double counting employees performing
that operation who are employed in the electroplating job shop
category). OSHA did not receive data or recommendations regarding
setting the PEL at any levels between 1 and 5 [mu]g/m\3\.
A Uniform PEL of 5 [mu]g/m\3\ Is Consistent With the Feasibility
Constraint of Section 6(b)(5)
    Section 6(b)(5) of the OSH Act requires OSHA to set the standard
which most adequately assures, to the extent feasible * * * that no
employee will suffer material impairment of health.'' This provision
requires the agency to eliminate or reduce significant risk, to the
extent feasible. See

American Textile Mfr. Inst., Inc. v. Donovan, 452 U.S. 490, 506-
22(1981). OSHA has always interpreted Section 6(b)(5) to accord the
agency substantial discretion to set the PEL at the lowest level that
is feasible for industries and operations as a whole. OSHA has not
interpreted the provision to require setting multiple PELs based on the
lowest level particular industries or operations could achieve. Because
Congress did not speak to the precise issue in the statute, OSHA has
authority to adopt the reasonable interpretation that it judges will
best carry out the purposes of the Act. Chevron U.S.A. v. Natural
Resources Defense Council, 467 U.S. 837 (1984).
    The new Cr(VI) standard meets the requirements of Section 6(b)(5)
because the PEL of 5 [mu]g/m\3\ is the lowest feasible limit for many
operations and sectors employing a large number of covered employees in
fact, a majority of affected employees. In addition, the record does
not afford a basis for any further disaggregation.
    OSHA recognizes that, according to the determination made in
Section VII of this preamble, significant risk remains at a PEL of 5
[mu]g/m\3\. As indicated in Table VII-3 in the Significance of Risk
section, the remaining risk for a worker exposed at the PEL throughout
a 45-year working lifetime is comparable to or greater than the
remaining risk in previous OSHA health standards where quantitative
estimates have been presented. Although OSHA anticipates that the
ancillary provisions of the standard will reduce this residual risk,
the Agency realizes that lower PELs might be achievable in some
industries and operations, which would reduce this risk even further.
As explained below, however, OSHA concludes that these benefits would
be offset by the significant disadvantages of attempting to establish
and apply multiple PELs for the diverse group of industries and
operations covered by the standard. See Building & Constr. Trades Dep't
v. U.S. Dep't of Labor, 838 F.2d 1258, 1273 (D.C. Cir. 1988)
(administrative difficulties, if appropriately spelled out, could
justify a decision to select a uniform PEL).
    Requiring OSHA to set multiple PELs--taking into account the
feasibility considerations unique to each industry or operation or
group of them--would impose an enormous evidentiary burden on OSHA to
ascertain and establish the specific situations, if any, in which a
lower PEL could be reached. Such an onerous obligation would inevitably
delay, if not preclude, the adoption of important health standards. In
addition, the demanding burden of setting multiple PELs would be
complicated by the difficulties inherent in precisely defining and
clearly distinguishing between affected industries and operations where
the classification determines legal obligations. The definitional and
line-drawing problem is far less significant when OSHA merely uses a
unit of industries and operations for analytical but not compliance
purposes, and when it sets a PEL in the aggregate, i.e., when its
analysis is limited to determining whether a particular PEL is the
lowest feasible level for affected industries as a whole. If OSHA had
to set multiple PELs, and assign industries or operations to those
PELs, the problem would become much more pronounced as the consequences
of imprecise classifications would become much more significant.
    The North American Industry Classification System (NAICS), which
has replaced the Standard Industrial Classification (SIC) system as the
standard Federal statistical agencies use in classifying business
establishments, is not an appropriate basis for establishing multiple
PELs. NAICS classifications are based on generally-worded definitions
and it is not always clear which definition best fits a particular
establishment. Moreover, an establishment's NAICS classification is
based on its primary activity. The establishment may include many other
activities, however, and what is the lowest feasible level for
operations in one activity may not be so for other activities. In
addition, the primary activity in an establishment may change over time
and the NAICS system itself is subject to revision every five years.
Definitional uncertainties, the presence of multiple and changing
business activities, and periodic revisions in individual codes could
have important consequences for enforcement of the standard over time.
For these reasons, OSHA has historically been reluctant to disaggregate
coverage of a standard by SIC classification. See 58 FR<PHONE_NUMBER>1
(March 30, 1993) (discussing disaggregation of coverage of lockout/
tagout standard).
    Similarly, disaggregation by operation has major practical
disadvantages. In addition to definitional complexities, a significant
problem with the use of operations for disaggregating the PEL is that
many firms have exposures in two or more different categories. Welding,
for example, is widely used in manufacturing operations in general
industry, maritime and construction. So, for instance, setting the PEL
at 5 for welding applications and 1 for other applications would mean
that some firms would have to attain two different PELs for Cr(VI)
exposures within the same workplace, and possibly even for the same
employees. As another example, chromium conversion is a process where a
treated metal surface is converted to a layer containing a complex
mixture of chromium compounds. Unlike electroplating, chromium
conversion is an entirely chemical process, and results in lower Cr(VI)
exposures than are typically associated with chromium electroplating.
Where chromium conversion is performed along with chromium
electroplating in a single establishment, it may be virtually
impossible to distinguish exposures from one source versus the other.
The same workers may even perform both tasks. Exposures from hard
chrome electroplating inevitably affect other nearby workers because
hard chrome plating is often done in the same workplaces or areas and
even at the same time as other operations involving lower Cr(VI)
exposures such as decorative plating and chrome conversion. In fact, in
many circumstances it can be virtually impossible to distinguish the
different sources that contribute to a particular employee's exposure
levels.
    These are just a few examples of the many instances reflected in
the record in which individual employers will have Cr(VI) exposures
emanating from two or more different operations (Exs. 38-233, pp. 9-10;
39-52, p. 4; 47-24, p. 2; 39-20, p. 5). If multiple PELs were
established for different operations, employers would be forced to
monitor for compliance with two or more PELs within the same
workplace--a task rendered all the more difficult by the fact that the
exposure of an employee may not be tied exclusively to a single task;
different processes may be performed in close proximity to one another
and each may contribute to the exposure of an individual.
    OSHA also believes that a uniform PEL will ultimately make the
standard more effective by making it easier for affected employers to
understand and comply with the standard's requirements. A uniform PEL
also makes it easier for OSHA to provide clear guidance to the
regulated community and to identify non-compliant conditions.
    Finally, OSHA is concerned that adopting multiple PELS could result
in a great number of subcategories that would have to be tracked for
enforcement purposes. Apart from welding and electroplating, which
present particularly severe

dissagregation problems, there are over thirty other industry sectors
with exposure to Cr(VI). None of these sectors individually accounts
for more than 6% of the total of exposed employees; in fact, several of
those groups employ fewer than 100 employees.
    For these reasons, OSHA has historically interpreted section
6(b)(5) to accord the Agency substantial discretion to set the PEL at
the lowest level feasible for industries or operations as a whole. In
adopting the arsenic standard, for example, OSHA expressly declined to
set different PELS, finding that ``[s]uch an approach would be
extremely difficult to implement.'' 43 FR 19584, 19601 (May 5, 1978).
In that instance, OSHA explained:

    The approach OSHA believes appropriate and has chosen for this
and other standards is the lowest level achievable through
engineering controls and work practices in the majority of
locations. This approach is intended to provide maximum protection
without excessively heavy respirator use. Id.

Similarly, when OSHA initially lowered the PEL for benzene from 10 ppm
to 1 ppm, it considered, but rejected, the idea of establishing
additional lower PELs, concluding that ``different levels for different
industries would result in serious administrative difficulties.'' 43 FR
5918, 5947 (Feb. 10, 1978). And when OSHA subsequently reconsidered the
benzene standard after it was remanded for a more specific finding of
significant risk, OSHA considered, but rejected, a PEL of 0.5 ppm,
noting:

    The unions have pointed out some situations where controls might
do somewhat better than 1 ppm * * * [but] OSHA believes it has
chosen the correct balance at 1 ppm as the level it can have a high
degree of confidence is generally achievable. 52 FR 34460, 34519
(Sept. 11, 1987).

    In the case of cotton dust, where OSHA did set different PELs for
certain discrete groups, the groups involved exposures to different
kinds of cotton dust and different degrees of risk. Even so, OSHA
declined to adopt a unique PEL for every single affected sector. See 43
FR 27350, 37360-61 (June 23, 1978) (OSHA set one PEL for textile
industries and a separate PEL for non-textile industries, but expressly
rejected the option of adopting different exposure limits for each non-
textile industry).
    In conclusion, the new PEL is the lowest level that can feasibly be
attained for many industries and operations employing a large number of
covered workers, in fact a majority of employees exposed to hexavalent
chromium. Considering all of the factors outlined above, OSHA finds
that a uniform PEL of 5 [mu]g/m\3\ is consistent with section 6(b)(5)
and that further dissagregation is not warranted.
    A Short-term Exposure Limit is Unnecessary. Several commenters
recommended that OSHA establish a short-term exposure limit (STEL) for
Cr(VI) (Exs. 38-219; 38-222; 39-38; 39-50; 40-19). By restricting
potential high magnitude exposures of short duration, a STEL is
intended to protect against health effects associated with relatively
high exposures, as well as to reduce cumulative exposures. The UAW
indicated that the high residual risk of cancer justified a STEL (Ex.
40-19), while NIOSH stated that short-term exposures to high levels of
Cr(VI) can cause severe respiratory effects (40-10-2, p. 17). Other
commenters did not believe a STEL was justified, in some cases noting
that neither NIOSH nor ACGIH recommends a STEL for Cr(VI) (Exs. 38-214;
38-220; 39-19; 39-20; 39-40; 39-41; 39-47; 39-51; 39-52; 39-60; 43-26).
    OSHA decided not to include a STEL in the final Cr(VI) standard for
three reasons. First, employers already are required to reduce
exposures to levels at or below the new PEL, which is expected to limit
the occurrence of high exposure excursions. Although it will not
eliminate all risk from peak exposures, the Agency anticipates that
compliance with the new PEL will substantially reduce the frequency and
magnitude of high exposure excursions, and thereby minimize the
likelihood of adverse health effects resulting from peak exposures.
Second, although in theory imposing a STEL might further lower
cumulative exposures to Cr(VI), there is little record evidence
supporting this supposition. Third, in some application groups, such as
plastic colorant producers, employees are typically exposed to Cr(VI)
not only for short durations but also intermittently. The industry has
estimated that only 5% of pigments used contain Cr(VI) (Ex. 47-24-1).
For these users, compliance with a STEL might require the expenditure
of considerable resources without providing much additional protection
to workers. These resources could more effectively be allocated to
other forms of worker protection.
    Without better justification, OSHA does not consider establishment
of a STEL to be reasonably necessary or appropriate. OSHA has concluded
that a STEL would provide at most a de minimis health benefit.
(d) Exposure Determination
    Paragraph (d) of the final rule sets forth requirements for
determining employee exposures to Cr(VI). The requirements are issued
pursuant to Section 6(b)(7) of the OSH Act (29 U.S.C. 655) which
mandates that any standard promulgated under section 6(b) shall, where
appropriate, ``provide for monitoring or measuring of employee exposure
at such locations and intervals, and in such manner as may be necessary
for the protection of employees.''
    The purpose of requiring an assessment of employee exposures to
Cr(VI) includes: determination of the extent and degree of exposure at
the worksite; identification and prevention of employee overexposure;
identification of the sources of exposure to Cr(VI); collection of
exposure data so that the employer can select the proper control
methods to be used; and evaluation of the effectiveness of those
selected methods. Assessment enables employers to meet their legal
obligation to ensure that their employees are not exposed to Cr(VI) in
excess of the permissible exposure level and to notify employees of
their exposure levels, as required by section 8(c)(3) of the Act. In
addition, the availability of exposure data enables the PLHCP
performing medical examinations to be informed of the extent of
occupational exposures.
    The final requirements have been revised from those proposed in
response to comments received. In the proposed general industry
standard, OSHA included a requirement for initial exposure monitoring
in all workplaces covered by the rule, unless monitoring had been
performed in the previous 12 months, or the employer had data to
demonstrate that exposures would be below the action level. Periodic
monitoring was required at intervals determined by monitoring results
(i.e., at least every 6 months if exposures were at or above the action
level, at least every 3 months if exposures were above the PEL), and
additional monitoring was required when changes in the workplace
resulted in new or additional exposures to Cr(VI). These requirements
are similar to requirements for monitoring found in previous OSHA
substance-specific health standards, such as those for methylene
chloride (29 CFR 1910.1052) and 1,3-butadiene (29 CFR 1910.1051).
    The proposed standards for construction and shipyards did not
include provisions for exposure monitoring. OSHA did not propose
specific exposure monitoring requirements for construction and
shipyards because operations in these sectors are often of short
duration, and are performed under varying environmental conditions.
    In omitting exposure monitoring requirements from the proposed

standards for construction and shipyards, OSHA intended to provide
construction and shipyard employers with the flexibility to assess
Cr(VI) exposures in any manner they considered appropriate. It was not
the Agency's intent that employers ignore substantial exposures to
Cr(VI). Because the obligation to comply with the PEL would remain, the
employer would have to accurately characterize Cr(VI) exposures in
order to determine if they were in compliance. At the time of the
proposal, OSHA considered this performance-oriented approach a
reasonable way to determine employee exposures to Cr(VI) while avoiding
the more infeasible requirements of a scheduled monitoring approach
that might not be useful in construction and shipyard workplaces. This
performance-based approach was consistent with OSHA's standard for air
contaminants (29 CFR 1910.1000), which establishes PELs for over 400
substances but does not include specific requirements for exposure
monitoring.
    Construction and shipyard employers who expressed an opinion on the
issue generally supported the absence of specific exposure monitoring
requirements (e.g., Exs. 38-220; 38-235; 38-244). In addition to those
operations that involved changing conditions, employers argued that
periodic monitoring requirements were unnecessary when conditions did
not change (Exs. 38-124; 38-213, 38-215; 38-189, 38-191). For example,
the U.S. Navy stated:

    The prescriptive schedule of required air sampling has not
proved beneficial in assessing risks in shipyards * * * where there
has been virtually no change in conditions, yet costs for consistent
air sampling have been incurred on an annual basis without
informational benefit or added protection for workers. The
performance-based sampling approach * * * is protective, efficient,
and logical (Ex. 38-220).

A number of employers also supported a performance oriented approach
for exposure determination in general industry workplaces (Exs. 38-189;
38-191; 38-213; 38-215; 39-48). Some of these commenters argued that
Cr(VI) exposures in their workplaces were intermittent, variable, and
of short duration, and therefore similar to those found in construction
and shipyards (Exs. 38-203; 38-254; 39-19; 39-48; 39-56). Other
comments focused on requirements for periodic monitoring that were
considered to be excessive (e.g., Exs. 38-124; 38-189; 38-191; 38-213;
38-215; 38-233). For example, the Color Pigments Manufacturers
Association stated:

    OSHA continues to require repeated monitoring at great cost in
general industry under circumstances where no change in procedure,
process, equipment or exposure has occurred to warrant repeated
exposure monitoring. This requirement is unnecessary and punitive.
It forces general industry to expend valuable resources on continual
monitoring without reason (Ex. 38-205).

Some employers, while maintaining that periodic monitoring requirements
were not warranted, indicated that initial exposure monitoring or an
initial hazard assessment would be appropriate (Exs. 38-214; 38-245-1).
    Other commenters, including unions, Public Citizen, and NIOSH,
supported explicit requirements for exposure assessment (Exs. 38-199-1;
38-222; 40-10-2; 47-23, p. 16). These parties argued that employers
will not know whether or not they are in compliance with the standard
without mandated exposure monitoring. For example, the Building and
Construction Trades Department, AFL-CIO, stated:

    If OSHA indeed intends construction employers to conduct an
exposure assessment, this requirement must be explicitly stated in
the regulation. To suggest that employers will attempt to
characterize exposure routinely without an explicit requirement in
the regulation is ludicrous (Ex. 38-219).

Even where controls are implemented, it was argued, exposure assessment
is still necessary to ensure that those controls are adequately
protective (Ex. 38-219). NIOSH suggested that OSHA might want to
consider developing alternative means for assessing exposures, such as
the use of interim protection provisions in construction for certain
tasks until exposure monitoring could be done (see the lead standard,
29 CFR 1926.62(d)) and the use of grouped tasks and grouping job types
into classes based on exposure potential (see the asbestos standard, 29
CFR 1926.1101) (Ex. 40-10-2, p. 19).
    After considering the evidence and arguments advanced by rulemaking
participants, OSHA is convinced that requirements for scheduled initial
and periodic Cr(VI) exposure monitoring are not appropriate in all
circumstances. In particular, OSHA believes that the evidence in this
rulemaking, as discussed earlier in this section in paragraph (c),
permissible exposure limit, demonstrates the varied nature of Cr(VI)
exposures across a number of different work operations. However, OSHA
also believes that valid concerns have been raised regarding the
adequacy of exposure assessments that would be performed in the absence
of explicit requirements. The Agency is therefore including in the
final rule two alternative options for all affected employers to follow
for determining employee exposures to Cr(VI). The first option,
referred to as the ``scheduled monitoring option'', consists of
requirements for initial monitoring and periodic monitoring at
intervals based on monitoring results. This approach is similar to that
proposed for general industry in this rulemaking and with exposure
assessment requirements in previous OSHA substance-specific standards.
The second option, referred to as the ``performance-oriented option'',
allows employers to use any combination of air monitoring data (i.e.,
data obtained from initial and periodic monitoring performed in
accordance with the requirements of the Cr(VI) standard), historical
monitoring data, or objective data to determine employee exposures to
Cr(VI), as long as the data are sufficient to accurately characterize
exposures.
    OSHA believes that by including explicit requirements for exposure
determination in the standards for general industry, construction, and
shipyards, the Agency makes clear the obligation of employers to
accurately assess employee exposures to Cr(VI) in all sectors. By
offering two options for achieving this goal, the final rule provides a
framework that is familiar to many employers and has been successfully
applied in the past, as well as flexibility for employers who are able
to characterize employee exposures through alternative methods.
    OSHA has chosen not to use the task-based approaches suggested by
NIOSH (Ex. 40-10-2) that the Agency has used in several previous health
standards covering construction. While OSHA believes that these
approaches are effective in certain construction settings, there was
not sufficient information in this rulemaking record for OSHA to
develop classes of exposures that would apply across the many varied
work operations with Cr(VI) exposures. While it was not possible to
develop specific classes of operations to apply across all industries,
OSHA believes that an individual employer, with specific information
about the work processes at his worksite, may be able to use such an
approach in using the performance-based option allowed by this final
rule.
    Paragraph (d)(2) contains requirements for employers who choose the
scheduled monitoring option. Employers who select this option must
conduct initial monitoring to determine employee exposure to Cr(VI).
OSHA has not established a separate compliance date for initial
monitoring to allow employers flexibility in scheduling this activity.
However, employers must

allow sufficient time after initial monitoring is performed to achieve
compliance (e.g., establish regulated areas, provide appropriate
respiratory protection) by the start-up dates specified in paragraph
(n) (paragraph (l) for construction and shipyards). Monitoring to
determine employee exposures must represent the employee's time-
weighted average exposure to airborne Cr(VI) over an eight-hour
workday. Samples must be taken within the employee's breathing zone
(i.e., ``personal breathing zone samples'' or ``personal samples''),
and must represent the employee's exposure without regard to the use of
respiratory protection.
    Employers must accurately characterize the exposure of each
employee to Cr(VI). In some cases, this will entail monitoring all
exposed employees. In other cases, monitoring of ``representative''
employees is sufficient. Representative exposure sampling is permitted
when a number of employees perform essentially the same job under the
same conditions. For such situations, it may be sufficient to monitor a
fraction of these employees in order to obtain data that are
``representative'' of the remaining employees. Representative personal
sampling for employees engaged in similar work with Cr(VI) exposure of
similar duration and magnitude is achieved by monitoring the
employee(s) reasonably expected to have the highest Cr(VI) exposures.
For example, this may involve monitoring the Cr(VI) exposure of the
employee closest to an exposure source. This exposure result may then
be attributed to the remaining employees in the group.
    Exposure monitoring should include, at a minimum, one full-shift
sample taken for each job function in each job classification, in each
work area, for each shift. These samples must consist of at least one
sample characteristic of the entire shift or consecutive representative
samples taken over the length of the shift. Where employees are not
performing the same job under the same conditions, representative
sampling will not adequately characterize actual exposures, and
individual monitoring is necessary.
    Employers who have workplaces covered by the standard must
determine if any of their employees are exposed to Cr(VI) at or above
the action level. Further obligations under the standard are based on
the results of this assessment. These may include obligations for
periodic monitoring, establishment of regulated areas, implementation
of control measures, and provision of medical surveillance.
    Requirements for periodic monitoring depend on the results of
initial monitoring. If the initial monitoring indicates that employee
exposures are below the action level, no further monitoring is required
unless changes in the workplace result in new or additional exposures.
If the initial determination reveals employee exposures to be at or
above the action level but at or below the PEL, the employer must
perform periodic monitoring at least every six months. If the initial
monitoring reveals employee exposures to be above the PEL, the employer
must repeat monitoring at least every three months.
    The scheduled monitoring option also includes provisions to adjust
the frequency of periodic monitoring based on monitoring results. If
periodic monitoring results indicate that employee exposures have
fallen below the action level, and those results are confirmed by
consecutive measurements taken at least seven days apart, the employer
may discontinue monitoring for those employees whose exposures are
represented by such monitoring. Similarly, if periodic monitoring
measurements indicate that exposures are at or below the PEL but at or
above the action level, the employer may reduce the frequency of the
monitoring to at least every six months.
    OSHA recognizes that exposures in the workplace may fluctuate.
Periodic monitoring provides the employer with assurance that employees
are not experiencing higher exposures that may require the use of
additional control measures. In addition, periodic monitoring reminds
employees and employers of the continued need to protect against the
hazards associated with exposure to Cr(VI).
    Because of the fluctuation in exposures, OSHA believes that when
initial monitoring results equal or exceed the action level but are at
or below the PEL, employers should continue to monitor employees to
ensure that exposures remain at or below the PEL. Likewise, when
initial monitoring results exceed the PEL, periodic monitoring allows
the employer to maintain an accurate profile of employee exposures. If
the employer installs or upgrades controls, periodic monitoring will
demonstrate whether or not controls are working properly. Selection of
appropriate respiratory protection also depends on adequate knowledge
of employee exposures.
    In general, the more frequently periodic monitoring is performed,
the more accurate the employee exposure profile. Selecting an
appropriate interval between measurements is a matter of judgment. OSHA
believes that the frequency of six months for subsequent periodic
monitoring for exposures at or above the action level but at or below
the PEL, and three months for exposures above the PEL, provides
intervals that are both practical for employers and protective for
employees. This belief is supported by OSHA's experience with
comparable monitoring intervals in other standards, including those for
cadmium (29 CFR 1910.1027), methylenedianiline (29 CFR 1910.1050),
methylene chloride (29 CFR 1910.1052), and formaldehyde (29 CFR
1910.1048).
    OSHA recognizes that monitoring can be a time-consuming, expensive
endeavor and therefore offers employers the incentive of discontinuing
monitoring for employees whose sampling results indicate exposures are
below the action level. The Agency does not believe that periodic
monitoring is generally necessary when monitoring results show that
exposures are below the action level because there is a low probability
that the results of future samples would exceed the PEL. Therefore the
final rule provides an incentive for employers to control their
employees' exposures to Cr(VI) below the action level to minimize their
exposure monitoring obligations while maximizing the protection of
employees' health.
    Under the scheduled monitoring option, employers are to perform
additional monitoring when there is a change in production process, raw
materials, equipment, personnel, work practices, or control methods,
that may result in new or additional exposures to Cr(VI). For example,
if an employer has conducted monitoring for an electroplating operation
while using fume suppressants, and the use of fume suppressants is
discontinued, then additional monitoring would be necessary to
determine employee exposures under the modified conditions. In
addition, there may be other situations which can result in new or
additional exposures to Cr(VI) which are unique to an employer's work
situation. For instance, a welder may move from an open, outdoor
location to an enclosed or confined space. Even though the task
performed and materials used may remain constant, the changed
environment could reasonably be expected to result in higher exposures
to Cr(VI). In order to cover those special situations, OSHA requires
the employer to perform additional monitoring whenever the employer has
any reason to believe that a change has occurred which may result in
new or additional

exposures. This additional monitoring is necessary to ensure that
monitoring results accurately represent existing exposure conditions.
This information will enable the employer to take appropriate action to
protect exposed employees, such as instituting additional engineering
controls or providing appropriate respiratory protection. On the other
hand, additional monitoring is not required simply because a change has
been made, if the change is not reasonably expected to result in new or
additional exposures to Cr(VI). For example, monitoring may be
conducted in an establishment when welding was performed on steel with
15% Cr content. If the establishment switches to a steel with 10% Cr
content without changing any other aspect of the work operation, then
additional exposures to Cr(VI) would not reasonably be expected, and
additional monitoring would not be required.
    The performance-oriented option allows the employer to determine
the 8-hour TWA exposure for each employee on the basis of any
combination of air monitoring data, historical monitoring data, or
objective data sufficient to accurately characterize employee exposure
to Cr(VI). This option is intended to allow employers flexibility in
assessing the Cr(VI) exposures of their employees. Where the employer
elects to follow this option, the exposure determination must be
performed prior to the time the work operation commences, and must
provide the same degree of assurance that employee exposures have been
correctly characterized as air monitoring would. The employer is
expected to reevaluate employee exposures when there is any change in
the production process, raw materials, equipment, personnel, work
practices, or control methods that may result in new or additional
exposures to Cr(VI).
    When using the term ``air monitoring data'' in this paragraph, OSHA
refers to initial and periodic Cr(VI) monitoring conducted to comply
with the requirements of this standard, including the prescribed
accuracy and confidence requirements. Historical monitoring data refers
to Cr(VI) monitoring data that was obtained prior to the effective date
of the final rule, where the data were obtained during work operations
conducted under workplace conditions closely resembling the processes,
types of material, control methods, work practices, and environmental
conditions in the employer's current operations, and where that
monitoring satisfies all other requirements of this section, including
the accuracy and confidence requirements described below.
    Objective data means information such as air monitoring data from
industry-wide surveys or calculations based on the composition or
chemical and physical properties of a substance demonstrating employee
exposure to Cr(VI) associated with a particular product or material or
a specific process, operation, or activity. The data must reflect
workplace conditions closely resembling the processes, types of
material, control methods, work practices, and environmental conditions
in the employer's current operations. Objective data demonstrate the
Cr(VI) exposures associated with a work operation or product under the
range of expected conditions of use. For example, data collected by a
trade association from its members may be used to determine exposures
to Cr(VI) provided the data meet the definition of objective data in
the standard.
    Previous OSHA substance-specific health standards have usually
allowed employers to use objective data to characterize employee
exposures, but have generally limited its use to demonstrating that
exposures would be below the action level (e.g., the Cadmium standard,
29 CFR 1910.1027(d)(2)(iii)). Likewise, use of historical monitoring
data has typically been allowed, but has usually been limited to data
obtained within the previous 12 months (e.g., the Methylene Chloride
standard, 29 CFR 1910.1052(d)(2)(ii)). In this instance, OSHA does not
place these limitations on the use of historical monitoring data or
objective data. However, the burden is on the employer to show that the
data comply with the requirements of this section. For example,
historical monitoring data obtained 18 months prior to the effective
date of the standard could be used to determine employee exposures, but
only if the employer could show that the data were obtained during work
operations conducted under workplace conditions closely resembling the
processes, types of material, control methods, work practices, and
environmental conditions in the employer's current operations, and that
the monitoring satisfies all other requirements of this section,
including the accuracy and confidence requirements. OSHA's intent is to
allow employers the greatest possible flexibility in methods used to
determine employee exposures to Cr(VI), but to ensure that the methods
used are accurate in characterizing employee exposures.
    Under paragraph (d)(4) of the final rule, employers covered by the
general industry standard must notify each affected employee within 15
working days if the exposure determination indicates that employee
exposure exceeds the PEL. In construction and shipyards, employers must
notify each affected employee as soon as possible but not more than 5
working days after the exposure determination indicates that employee
exposure exceeds the PEL. A shorter time period for notification is
provided in construction and shipyards in recognition of the often
short duration of operations and employment in particular locations in
these sectors. The time allowed for notification is consistent with the
harmonized notification times established for these sectors in Phase II
of OSHA's Standards Improvement Project (70 FR 1112 (1/5/05)). Where
the employer follows the scheduled monitoring option, the 15 (or 5)
working day period commences when monitoring results are received. For
employers following the performance-oriented option, the 15 (or 5)
working day period commences when the determination is made (i.e.,
prior to the time the work operation commences, and when exposures are
reevaluated).
    When using the term ``affected employees'' in this provision, OSHA
is referring to all employees considered to be above the PEL. This
would include employees who are not actually subject to personal
monitoring, but are represented by an employee who is sampled. Affected
employees also include employees whose exposures have been deemed to be
above the PEL on the basis of historical or objective data. The
employer shall either notify each affected employee in writing or post
the monitoring results in an appropriate location accessible to all
affected employees. In addition, whenever the PEL has been exceeded,
the written notification must contain a description of the corrective
action(s) being taken by the employer to reduce the employee's exposure
to or below the PEL. The requirement to inform employees of the
corrective actions the employer is taking to reduce the exposure level
to or below the PEL is necessary to assure employees that the employer
is making efforts to furnish them with a safe and healthful work
environment, and is required under section 8(c)(3) of the Act.
    Paragraph (d)(5) of the final rule requires the employer to use
monitoring and analytical methods that can measure airborne levels of
Cr(VI) to within an accuracy of plus or minus 25% (25%) and
can produce accurate measurements to within a statistical confidence
level of 95% for airborne concentrations at or above the action level.
Many laboratories presently have

methods to measure Cr(VI) at the action level with at least the
required degree of accuracy. One example of an acceptable method of
monitoring and analysis is OSHA method ID215, which is a fully
validated analytical method used by the Agency. (See Chapter III of the
FEA for a discussion of issues regarding methods of sampling and
analysis). Rather than specifying a particular method that must be
used, OSHA allows the employer to use any method as long as the chosen
method meets the accuracy specifications. This is consistent with the
general performance approach favored in the OSH Act.
    Paragraph (d)(6) requires the employer to provide affected
employees or their designated representatives an opportunity to observe
any monitoring of employee exposure to Cr(VI), whether the employer
uses the scheduled monitoring option or the performance-oriented
option. When observation of monitoring requires entry into an area
where the use of protective clothing or equipment is required, the
employer must provide the observer with that protective clothing or
equipment, and assure that the observer uses such clothing or equipment
and complies with all other required safety and health procedures.
    The requirement for employers to provide employees or their
representatives the opportunity to observe monitoring is consistent
with the OSH Act. Section 8(c)(3) of the OSH Act mandates that
regulations developed under Section 6 provide employees or their
representatives with the opportunity to observe monitoring or
measurements. Also, Section 6(b)(7) of the OSH Act states that where
appropriate, OSHA standards are to prescribe suitable protective
equipment to be used in dealing with hazards. The provision for
observation of monitoring and protection of the observers is also
consistent with OSHA's other substance-specific health standards such
as those for cadmium (29 CFR 1910.1027) and methylene chloride (29 CFR
1910.1052).
(e) Regulated Areas
    Paragraph (e) of the final rule requires general industry employers
to establish regulated areas wherever an employee's exposure to
airborne concentrations of Cr(VI) is, or can reasonably be expected to
be, in excess of the PEL. Regulated areas are to be demarcated from the
rest of the workplace in a manner that adequately establishes and
alerts employees to the boundaries of these areas. Access to regulated
areas is to be limited to persons authorized by the employer and
required by work duties to be present in the regulated area; any person
entering the regulated area to observe monitoring procedures; or any
person authorized by the OSH Act or regulations issued under it to be
in a regulated area.
    The purpose of a regulated area is to ensure that the employer
makes employees aware of the presence of Cr(VI) at levels above the
PEL, and to limit Cr(VI) exposure to as few employees as possible. The
establishment of a regulated area is an effective means of limiting the
risk of exposure to substances known to have carcinogenic effects.
Because of the potentially serious results of exposure and the need for
persons exposed above the PEL to be properly protected, the number of
persons given access to the area must be limited to those employees
needed to perform the job. Limiting access to regulated areas also has
the benefit of reducing the employer's obligation to implement
provisions of this standard to as few employees as possible.
    In keeping with the performance orientation of this standard, OSHA
has not specified how employers are to demarcate regulated areas. OSHA
proposed that warning signs be posted at all approaches to regulated
areas, and set forth specific language in paragraph (1) of the proposed
standard to be included on the warning signs. However, OSHA has
determined that other means of demarcation such as barricades, lines
and textured flooring, or signs using other language can be equally
effective in identifying the boundaries of regulated areas and
notifying employees of associated hazards, the need to restrict access
to such areas, and protective measures to be implemented. The specific
language for warning signs included in paragraph (1) of the proposal,
and the reference to that language in this provision, have therefore
been deleted from the final rule.
    In the final rule, OSHA thus has provided employers with the
flexibility to use the methods of demarcation that are most appropriate
for identifying regulated areas in their workplace. Factors that the
Agency believes are appropriate for employers to consider in
determining how to mark their areas include the configuration of the
area, whether the regulated area is permanent, the airborne Cr(VI)
concentration, the number of employees in adjacent areas, and the
period of time the area is expected to have exposure levels above the
PEL. Permitting employers to choose how best to identify and limit
access to regulated areas is consistent with OSHA's belief that
employers are in the best position to make such determinations, based
on their knowledge of the specific conditions of their workplaces.
Whatever methods are chosen, the demarcation must effectively warn
employees not to enter the area unless they are authorized, and then
only if they are using the proper personal protective equipment.
Allowing employers to demarcate and limit access to the regulated areas
as they choose is consistent with OSHA's two most recent substance-
specific health standards, addressing occupational exposure to
methylene chloride (29 CFR 1910.1052(e)) and 1,3-butadiene (29 CFR
1910.1051(e)).
    Access to the regulated area is restricted to ``authorized
persons.'' For the purposes of this standard, these are persons
required by their job duties to be present in the area, as authorized
by the employer. This may include maintenance and repair personnel,
management, quality control engineers, or other personnel if job duties
require their presence in the regulated area. In addition, persons
exercising the right to observe monitoring procedures are allowed to
enter regulated areas when exposure monitoring is being conducted.
Persons authorized under the OSH Act, such as OSHA compliance officers,
are also allowed access to regulated areas.
    In the final rule, OSHA has not included a requirement for
regulated areas in construction and shipyard workplaces, due to the
expected practical difficulties of establishing regulated areas for
operations in these sectors. OSHA raised the issue of requiring
regulated areas for these workplaces and received comments and
testimony from a variety of sources. A number of commenters supported
not requiring regulated areas in construction and shipyards (Exs. 38-
214; 38-220; 38-235; 38-236; 38-244; 39-37; 39-20; 39-40; 39-48; 39-64;
39-65). The National Association of Home Builders, for example,
indicated that regulated areas are not feasible on residential
construction jobsites because the area where exposures would exceed the
PEL could not be accurately determined, stating:

    Because of the fluid nature of construction work and the ever-
changing work environment, a regulated area could never be
accurately determined due to the fact that construction areas are
mostly exposed to the ambient environment. Factors such as shifting
winds, tight work areas and multiple operations adjacent to the
regulated area would create changes in air movement and would make
establishment of a regulated area unattainable (Ex. 38-244).

Associated Builders and Contractors concurred with this assessment, and
maintained that establishment of regulated areas could interfere with
construction operations:

    The nature of construction sites makes it extremely difficult to
close off certain areas from others without shutting down or
interfering with significant construction activities (Ex. 39-65).

    Some commenters maintained that certain activities should not be
subject to requirements for regulated areas (Exs. 38-7, p. 5; 38-124;
38-203; 38-205; 38-228; 38-233; 38-238; 38-254; 39-19; 39-56; 39-62).
The Office of Advocacy of the Small Business Administration, for
example, stated that requirements for regulated areas should be limited
to industries and processes where they would likely reduce exposures,
arguing that establishment of regulated areas would have the effect of
requiring respirators or other controls for more employees than
necessary (Ex. 38-7). Because regulated areas are required only where
exposures exceed the PEL, OSHA considers that these requirements are
limited to situations where they can reduce exposures. As mentioned
previously, making employees aware of potential exposures in excess of
the PEL and limiting the number of employees present in regulated areas
will effectively reduce exposures to Cr(VI). Moreover, establishment of
regulated areas will not result in additional requirements for
respirators or other controls, because requirements for these other
control measures are not directly related to the establishment of
regulated areas. Simply entering a regulated area, for example, does
not trigger a requirement for use of respiratory protection.
    Other commenters maintained that certain general industry
activities, or general industry as a whole, should not be subject to
the proposed requirements for regulated areas. Alabama Power, for
example, indicated that the same rationale used to justify the absence
of regulated area requirements in construction and shipyards also
applied to general industry environments such as power plants (Exs. 38-
254; 38-203). Others argued that regulated areas were not appropriate
for specific activities such as welding (Ex. 38-124), job shop
fabrication (Exs. 38-238; 39-62), or glass manufacturing (Ex. 38-228).
    Other commenters expressed support for regulated area requirements,
arguing that they were a feasible and useful means of protecting
workers, and should apply to construction and shipyards as well as
general industry workplaces (Exs. 38-199-1; 38-219; 38-222; 39-38; 39-
71; 40-10-2; 47-28). For example, NIOSH indicated that regulated areas
help minimize exposures to bystanders in construction and shipyard
worksites:

    * * * regulated areas are important on construction and shipyard
worksites because of the potential for ``bystander'' exposures given
that it is common for employees from different trades to work in
close proximity. For construction, bystander employees may work for
different employers, thus complicating control efforts (Ex. 40-10-
2).

Regulated areas, it was argued, are not unduly burdensome. Dr. Franklin
Mirer of the United Auto Workers, when asked if he foresaw problems
with requirements for regulated areas, stated:

    * * * you put a sign [up] and you tell people who don't have to
be there not to be there * * * what's burdensome about that? It's
like * * * putting up a sign on the ladies room. Certain people
can't go in that regulated area (Tr. 837).

    OSHA believes, however, that Dr. Mirer oversimplifies the
situation. The difficulty is not with the mere physical act of putting
up a sign at a regulated area, but rather with determining where, when,
and for how long a duration to establish a regulated area. Making these
determinations is very problematic given the varied and changing nature
of the operations involving Cr(VI) exposures at construction and
shipyard worksites. Moreover, areas where employees are exposed above
the PEL might change on a daily or even hourly basis and may occur at
different sites on the worksite than they did the day before, making it
unreasonably difficult to keep up with the posting (and removal) of
signs, barricades or other warning in a manner that would effectively
let employees know about the hazard.
    OSHA has concluded that requirements for regulated areas are
appropriate for general industry, but not for construction and
shipyards, because the work sites and conditions and other factors,
such as environmental variability normally present in construction and
shipyard employment, differ substantially from those typically found in
general industry. Construction and shipyard tasks are often of
relatively short duration; are commonly performed outdoors, sometimes
under adverse environmental conditions (e.g., wind, rain); and are
often performed at non-fixed workstations or work sites. Collectively,
these factors make establishment of regulated areas impracticable for
many construction and shipyard operations.
    These difficulties are particularly evident with regard to welding
operations in construction and shipyard workplaces. Welding is the
predominant source of Cr(VI) exposures in these sectors, accounting for
over 82% of employees exposed above the PEL in construction and over
73% of employees exposed above the PEL in shipyards. Welding operations
in construction and shipyards often involve movement to different
locations during the workday, and welding fumes are highly subject to
changes in air currents, meaning the exposure patterns can shift
rapidly.
    In the typical shipyard and construction project involving
exposure, it is difficult to determine appropriate boundaries for
regulated areas because the work and worksite are varied and subject to
environmental influences. Moreover, workers are often moving from place
to place throughout the site on a regular basis. While each employer
has the obligation under the requirements of paragraph (d) of this
final rule to determine Cr(VI) exposures for all employees, accurately
demarcating all areas where Cr(VI) exposures could potentially exceed
the PEL is a separate and potentially much more difficult undertaking.
In general industry environments, which are typically more stable,
likely to be indoors, and usually at a fixed location, this can
generally be accomplished with minimal difficulty. In construction and
shipyard workplaces, for the reasons described above, OSHA has
determined that establishing regulated areas to control exposures to
Cr(VI) can not reasonably be accomplished, and has therefore not
included a requirement for regulated areas for these sectors in the
final rule.
    The Agency realizes that in some cases general industry work
operations and work environments may be comparable to those found in
construction and shipyards, and where the general industry employer can
show compliance is not feasible, regulated areas will not have to be
established. However, OSHA believes its longstanding distinction
between these sectors provides an appropriate line for delineating
between those operations where the employer generally is reasonably
able to establish regulated areas where exposures to Cr(VI) exceed the
PEL versus operations where regulated areas are generally not
practicable.
    OSHA recognizes that the determination not to include requirements
for regulated areas for construction and shipyards in this final rule
differs from the determinations made in previous rulemakings. The AFL-
CIO pointed out that a number of

previous standards including those for asbestos, cadmium, benzene, 1,2-
dibromo-3-chloropropane, ethylene oxide, methylenedianiline,
formaldehyde, and 1,3 butadiene, included provisions for regulated
areas in construction (Exs. 38-222; 47-28-1). It is important to note,
however, that many of these standards such as benzene, 1,2-dibromo-3-
chloropropane, ethylene oxide, methylenedianiline, and formaldehyde
involved relatively few exposures in construction operations. For
example, in the preamble to the final benzene standard OSHA concluded
that while the standard would cover construction, ``The standard has
virtually no impact on construction'' (52 FR at 34527). Similarly,
requirements for regulated areas in the standard for cadmium in
construction did not pose major problems for employers, because few
workers were expected to be exposed above the PEL and thus subject to
requirements for regulated areas. More importantly, in the cadmium
rulemaking as in others discussed below, regulated areas for
construction were not at issue because so few employees were
potentially exposed above the PEL. Thus, the Agency did not address the
factors that were presented in this rulemaking.
    OSHA's standards for lead in construction and asbestos in
construction, on the other hand, affect relatively large numbers of
employers and employees. The standard for lead in construction is a
notable exception to the AFL-CIO's list. OSHA did not include
requirements for regulated areas in that standard (see 29 CFR 1926.62).
While the asbestos construction standard does include requirements for
regulated areas, the classification scheme for asbestos construction
operations (i.e., Class I, II, III and IV) and requirements for
enclosing many work operations makes establishment of regulated areas
easier for employers. (see 29 CFR 1926.1101). The Agency believes that
the broad scope of the Cr(VI) final rule for construction, similar to
the standard covering lead construction operations, would make
application of regulated area requirements substantially more difficult
than is the case for a standard with a much more limited scope, such as
the standards for cadmium or benzene in construction.
    Finally, in none of the previous health standards were the
particular difficulties of implementing regulated areas for shipyard
and construction work specifically considered as they have been in this
rulemaking. In this rulemaking, the establishment of regulated areas
was a major issue with a significant volume of comments and testimony,
allowing OSHA to fully consider the matter in light of the specific
nature of Cr(VI) exposures. First, OSHA's proposal did not include
regulated areas in construction and shipyard employment. Secondly, in
the proposal, OSHA included two general questions, numbers 31 and 32,
on modifying the requirements for construction and shipyard employment
and one very specific question, number 47, on whether regulated areas
should be included for construction and shipyard employment (69 FR
59452, 59310). Thus, the public had sufficient notice and OSHA was able
to weigh the evidence, ultimately finding the reasons for excluding
regulated areas from construction and shipyard employment persuasive.
(f) Methods of Compliance
    Paragraph (f) of the final rule (paragraph (e) for construction and
shipyards) establishes which methods must be used by employers to
comply with the PEL. It requires that employers institute effective
engineering and work practice controls as the primary means to reduce
and maintain employee exposures to Cr(VI) to levels that are at or
below the PEL unless the employer can demonstrate that such controls
are not feasible. Where the employer demonstrates that such controls
are not feasible, the final rule requires the employer to institute
engineering and work practice controls to reduce exposures to the
lowest feasible level. The employer is then required to supplement
these controls with respiratory protection to achieve the PEL.
    A number of commenters supported OSHA's inclusion of the hierarchy
of controls in the final Cr(VI) rule (e.g., Tr. 826, Exs. 38-232; 38-
235; 38-238; 39-20; 39-47; 40-10-2; 47-23; 47-26). For example, NIOSH
endorsed the use of engineering and work practice controls as primary
methods of controlling exposures to Cr(VI) (Ex. 40-10-2). Personal
protective equipment such as respirators was regarded by NIOSH as the
last line of defense, to be used only when engineering controls are not
feasible. Other commenters objected to OSHA's proposed application of
the hierarchy of controls in the Cr(VI) rule, arguing that use of
respiratory protection instead of engineering controls should be
allowed in a variety of different situations (e.g., Exs. 38-204; 38-
215; 38-216-1; 38-218; 38-233; 39-51; 39-66; 43-14; 47-30; 47-31; 47-
32). For example, the National Paint and Coatings Association contended
that respirator use should be permitted in paint and coatings
manufacture:

    * * * exposures to hexavalent chromium compounds are limited in
time and place, and their handling is seldom encountered by
other[sic] than a relatively small number of workers, whose use of
respirators would not pose most of the problems OSHA associates with
respirators * * * (Ex. 39-66).

    OSHA is requiring primary reliance on engineering controls and work
practices because reliance on these methods is consistent with good
industrial hygiene practice, with the Agency's experience in assuring
that workers have a healthy workplace, and with the Agency's
traditional adherence to a hierarchy of preferred controls. Engineering
controls are reliable, provide consistent levels of protection to a
large number of workers, can be monitored, allow for predictable
performance levels, and can efficiently remove a toxic substance from
the workplace. Once removed, the toxic substance no longer poses a
threat to employees. The effectiveness of engineering controls does not
generally depend to any substantial degree on human behavior, and the
operation of equipment is not as vulnerable to human error as is
personal protective equipment.
    Engineering controls can be grouped into three main categories: (1)
Substitution; (2) isolation; and (3) ventilation, both general and
localized. Quite often a combination of these controls can be applied
to an industrial hygiene control problem to achieve satisfactory air
quality. It may not be necessary to apply all these measures to any
specific potential hazard.
    Substitution can be an ideal control measure. One of the best ways
to prevent workers from being exposed to a toxic substance is to stop
using it entirely. Although substitution is not always possible,
replacement of a toxic material with a less hazardous alternative
should always be considered.
    In those cases where substitution of a less toxic material is not
possible, substituting one type of process for another process may
provide effective control of an air contaminant. For example, process
changes from batch operations to continuous operations will usually
reduce exposures. This is true primarily because the frequency and
duration of workers' potential contact with process materials is
reduced in continuous operations. Similarly, automation of a process
can further reduce the potential hazard.
    In addition to substitution, isolation should be considered as an
option for controlling employee exposures to

Cr(VI). Isolation can involve containment of the source of a hazard,
thereby separating it from most workers. Workers can be isolated from
Cr(VI) by working in a clean room or booth, or by placing some other
type of barrier between the source of exposure and the employee.
Employees can also be protected by being placed at a greater distance
from the source of Cr(VI) emissions.
    Frequently, isolation enhances the benefits of other control
methods. For example, Cr(VI) compounds may be used in the formulation
of certain paints. If the mixing operation is conducted in a small,
enclosed room the airborne Cr(VI) potentially generated by the
operation could be confined to a small area. By ensuring containment,
local exhaust ventilation is more effective.
    Ventilation is a method of controlling airborne concentrations of a
contaminant by supplying or exhausting air. A local exhaust system is
used to remove an air contaminant by capturing the contaminant at or
near its source before it spreads throughout the workplace. General
ventilation (dilution ventilation), on the other hand, allows the
contaminant to spread throughout the work area but dilutes it by
circulating large quantities of air into and out of the area. A local
exhaust system is generally preferred to dilution ventilation because
it provides a cleaner and healthier work environment.
    Work practice controls involve adjustments in the way a task is
performed. In many cases, work practice controls complement engineering
controls in providing worker protection. For example, periodic
inspection and maintenance of process equipment and control equipment
such as ventilation systems is an important work practice control.
Frequently, equipment which is in disrepair or near failure will not
perform normally. Regular inspections can detect abnormal conditions so
that timely maintenance can then be performed. If equipment is
routinely inspected, maintained, and repaired or replaced before
failure is likely, there is less chance that hazardous exposures will
occur.
    Workers must know the proper way to perform their job tasks in
order to minimize their exposure to Cr(VI) and to maximize the
effectiveness of control measures. For example, if an exhaust hood is
designed to provide local ventilation and a worker performs a task that
generates a contaminant away from the exhaust hood, the control measure
will be of no use. Workers can be informed of proper operating
procedures through information and training. Good supervision further
ensures that proper work practices are carried out by workers. By
persuading a worker to follow proper procedures, such as positioning
the exhaust hood in the correct location to capture the contaminant, a
supervisor can do much to minimize unnecessary exposure.
    Employees' exposures can also be controlled by scheduling
operations with the highest exposures at a time when the fewest
employees are present. For example, routine clean-up operations that
involve Cr(VI) releases might be performed at night or at times when
the usual production staff is not present.
    Respirators are another important, although less preferred, method
of compliance. However, to be effective, respirators must be
individually selected; fitted and periodically refitted;
conscientiously and properly worn; regularly maintained; and replaced
as necessary. In many workplaces, these conditions for effective
respirator use are difficult to achieve. The absence of any of these
conditions can reduce or eliminate the protection the respirator
provides to some of all of the employees.
    Respirator effectiveness ultimately relies on the good work
practices of individual employees. In contrast, the effectiveness of
engineering controls does not rely so routinely on actions of
individual employees. Engineering and work practice controls are
capable of reducing or eliminating a hazard from the workplace as a
whole, while respirators protect only the employees who are wearing
them correctly. Furthermore, engineering and work practice controls
permit the employer to evaluate their effectiveness directly through
air monitoring and other means. It is considerably more difficult to
directly measure the effectiveness of respirators on a regular basis to
ensure that employees are not unknowingly being overexposed. OSHA
therefore considers the use of respirators to be the least satisfactory
approach to exposure control.
    In addition, use of respirators in the workplace presents other
safety and health concerns. Respirators can impose substantial
physiological burdens on employees, including the burden imposed by the
weight of the respirator; increased breathing resistance during
operation; limitations on auditory, visual, and odor sensations; and
isolation from the workplace environment. Job and workplace factors
such as the level of physical work effort, the use of protective
clothing, and temperature extremes or high humidity can also impose
physiological burdens on workers wearing respirators. These stressors
may interact with respirator use to increase the physiological strain
experienced by employees.
    Certain medical conditions can compromise an employee's ability to
tolerate the physiological burdens imposed by respirator use, thereby
placing the employee wearing the respirator at an increased risk of
illness, injury, and even death. These medical conditions include