40; 2319, pp. 90-91; 2337, p. 2; 2339, p. 8; 2357, pp. 29-30; 2363, p.
6; 3577, Tr. 713-714; 3580, Tr. 1376-1377; 3584, Tr. 2669; 4035, p. 9).
Many contended that the language in the provision was vague or
subjective. For example, the Tile Council of North America, the
National Tile Contractors Association, and Morgan Advanced Materials
argued that the term ``grossly'' is subjective, and its use in this
context would subject the employer to the whim of the compliance
inspector (Document ID 2267, p. 6; 2363, p. 6; 2337, p. 2).
    The American Society of Safety Engineers (ASSE) indicated that no
special clothing should be required, as crystalline silica does not
present a hazard from skin contact. Instead, ASSE suggested that
employers need to implement programs to assure employees whose clothing
is contaminated with crystalline silica do not create exposure issues
outside of the workplace (Document ID 2339, p. 8). NAHB argued that
protective clothing such as coveralls would be difficult for workers in
residential construction to use because coveralls frequently restrict
movement, are often not durable enough for the conditions encountered
in construction, and could contribute to heat stress (Document ID 2296,
p. 40).
    The evidence regarding the extent to which dust-contaminated
clothing may exacerbate employee exposure to respirable crystalline
silica is mixed. NIOSH stated that past studies have shown a
significant increase in workers' respirable dust exposure from
contaminated work clothing, referencing a Bureau of Mines study
involving highly-exposed machine operators bagging mineral products
into paper bags (Document ID 2177, Attachment B, p. 15). On the other
hand, the National Industrial Sand Association (NISA) stated that:

    NISA member companies have years of experience conducting root
cause analyses of exceedances of the PEL. In that experience,
contaminated work clothing can be the source of such an exceedance,
but such circumstances are uncommon (Document ID 2195, p. 37).

    OSHA agrees that contaminated work clothing can contribute to
respirable dust exposures in some circumstances, as NIOSH indicated.
However, OSHA concludes that the evidence in the rulemaking record does
not show that contaminated work clothing contributes appreciably to
employee exposures to respirable crystalline silica in workplace
conditions covered by this rule. OSHA is therefore not including a
requirement for protective clothing in the rule because it is unable to
determine that the use of protective clothing would

provide appreciable protection from inhalation of respirable
crystalline silica in most circumstances. OSHA understands that many of
the activities covered under the rule involve generation of substantial
amounts of dust. However, the dust of concern in this rulemaking is
composed only of respirable crystalline silica particles--those
particles small enough to penetrate deep into the lungs. OSHA proposed
protective clothing requirements in regulated areas in an attempt to
focus on those areas in the workplace where high exposures to
respirable crystalline silica occur. However, it is not clear that
measures to address dust on employees' clothing are likely to have any
meaningful effect on exposures to respirable crystalline silica in most
workplaces covered by the rule.
    Protective clothing is primarily designed to mitigate against
dermal hazards, which are not the problem here; nor is dermal exposure
(as opposed to respiratory exposure) the mechanism by which silica
causes its adverse health effects. Therefore, special or employer-
provided protective clothing would be no more protective than ordinary
clothing in this context. Moreover, OSHA understands the practical
difficulty that employers would encounter in attempting to determine
when clothing is sufficiently contaminated to trigger a requirement for
protective measures. Therefore, OSHA has not included a requirement for
employers to provide protective work clothing or other means of
removing silica dust from clothing in the rule. There may be instances
where providing protective clothing or other means of removing
excessive silica dust from clothing are feasible methods of limiting
employee exposures to respirable crystalline silica; in such cases,
these methods become an option for complying with the requirement to
limit employee exposures to the PEL.
    OSHA has also decided not to include the proposed option to
establish and implement an access control plan in lieu of a regulated
area in the rule. As noted above, paragraph (e)(1) of the proposed
standards for general industry/maritime and construction would have
required the establishment and implementation of either a regulated
area or an access control plan wherever an employee's exposure to
airborne concentrations of respirable crystalline silica is, or
reasonably could be expected to be, in excess of the PEL. OSHA
recognized that establishing regulated areas in some workplaces might
be difficult. As such, the Agency proposed an option for establishing
and implementing a written access control plan in lieu of a regulated
area.
    The option for a written access control plan contained provisions
for: A competent person to identify the presence and location of areas
where respirable crystalline silica exposures exceed the PEL; notifying
employees and demarcating such areas; communicating with other
employers on multi-employer worksites; limiting access to areas where
exposures exceed the PEL; providing respirators; and addressing
measures regarding contaminated work clothing. The proposed rule also
included a requirement for an annual employer review and evaluation of
the written access control plan, and the plan was to be made available
upon request for examination and copying to employees, their
representatives, and the Assistant Secretary and the Director.
    The intent of the provision for establishing written access control
plans in lieu of regulated areas was to provide employers with
flexibility to adapt to the particular circumstances of their worksites
while maintaining equivalent protection for employees. The option for
establishing a written access control plan was thought to be best
suited for changing or mobile worksites such as those found in
construction and utilities.
    The North American Insulation Manufacturers Association supported
the option for a written access control plan, claiming that it is
similar to current mineral wool industry practices for limiting access
(Document ID 2348, p. 36). The National Concrete Masonry Association
and approximately five of its member companies stated that access
control plans may be effective for tasks in which personal protective
equipment is needed (e.g., mixer cleaning), but not for operations that
cannot be performed in a controlled, limited areas (e.g., general plant
clean-up) (e.g., Document ID 2279, p. 10; 2388, p. 9).
    Commenters including American Subcontractors Association (ASA),
Leading Builders of America (LBA), NAHB, and the Construction Industry
Safety Coalition (CISC), thought that a written access control plan was
impractical in the construction industry, stating reasons such as
uncertainty about its requirements or how such plans would differ from
a regulated area (e.g., Document ID 2187, p. 5; 2269, p. 22; 2296, pp.
25-26; 2319, pp. 88-89). Additionally, the Communication Workers of
America (CWA), UAW, and AFL-CIO felt that, given issues of
enforceability, it did not appear the written access control plan would
adequately protect workers and limit access to high-exposure work
areas. Thus, CWA, UAW, and AFL-CIO recommended elimination of the
option for a written access plan, and for the provision to be limited
to a regulated areas requirement only (Document ID 2240, p. 2; 2282,
Attachment 3, p. 16; 3578, Tr. 924-925). Fann Contracting, Inc.
indicated that neither written access control plans nor regulated areas
were conducive to outdoor, heavy highway and road and bridge
construction where the entire worksite has potential for silica
exposure (Document ID 2116, Attachment 1, pp. 26-27).
    OSHA concludes that the option for a written access control plan
may prove less protective and would be difficult to enforce, so has
decided not to include the option for employers to develop and maintain
written access control plans in lieu of regulated areas in the rule.
OSHA no longer views a written access control plan to be a viable
substitute for establishment and maintenance of regulated areas in the
rule, especially in light of its decision not to include a regulated
areas requirement in the standard for construction. The requirement for
a competent person in paragraph (g)(4) of the standard for construction
provides an alternate approach to restricting access to areas where
high exposures can occur, and OSHA's expectation is that it will
achieve a comparable level of protection without imposing the burden of
maintaining a written access control plan.
    The decision not to require regulated areas in the standard for
construction reflects OSHA's acknowledgment of the impracticality of
establishing and demarcating regulated areas in many construction
industry workplaces. However, as described in further detail in the
summary and explanation of Written Exposure Control Plan, OSHA has
concluded that implementing a written exposure control plan, which
includes a requirement to describe procedures to restrict access to
work areas, is practical in construction industry workplaces. OSHA
notes that a written access control plan as contemplated in the
proposed rule is different from a written exposure control plan as
mandated in the rule. Written exposure control plans are included in
the industry consensus standards: ASTM E 1132-06, Standard Practice for
Health Requirements Relating to Occupational Exposure to Respirable
Crystalline Silica and ASTM E 2625-09, Standard Practice for
Controlling Occupational Exposure to Respirable Crystalline Silica for
Construction and Demolition Activities

(Document ID 1466, p. 2; 1504, p. 2). OSHA finds that written exposure
control plans provide a systematic approach for ensuring proper
function of engineering controls and effective work practices that can
prevent overexposures from occurring. The ASTM standards do not
specifically call for procedures to restrict access; however, they do
call for a description of administrative controls to reduce exposures
(Document ID 1466, p. 2; 1504, p. 2). An example of such an
administrative control for minimizing the number of employees exposed
to respirable crystalline silica would be to schedule high-exposure
tasks to be conducted when others will not be in adjacent areas
(Document ID 3583, Tr. 2385-2386).
    Commenters from the construction industry submitted comments on the
regulated area option. Some of the comments were generally supportive
(Document ID 2169, p. 4; 2177, Attachment B, p. 14; 2262, pp. 43-44;
2339, p. 4). However, other stakeholders felt that OSHA's proposed
requirements for regulated areas would be unworkable and infeasible in
construction (e.g., Document ID 2116, Attachment 1, p. 13; 2183, pp. 1-
2; 2187, p. 5-6; 2269, p. 4; 2276, p. 5; 2319, pp. 89-90; 2323, p. 1;
2338, p. 3; 2345, p. 3). They expressed serious concerns with the
proposed provisions for establishing and limiting access to regulated
areas, often citing challenges posed by constantly changing work
activities, multiple employers on the worksite, lack of employer
control in outside construction projects, the possibility of an entire
worksite needing to be classified as a regulated area (on small
worksites), and the prevalence of silica in the natural environment,
particularly in certain regions of the country (e.g., Document ID 2116,
pp. 13-14, 22, 27; 2183, pp. 1-2; 2319, p. 89; 2323, p. 1; 2210,
Attachment 1, p. 7; 2187, pp. 5-6; 2246, p. 11; 2269, p. 22; 2296, p.
26; 3230, p. 2). For example, ASA questioned a subcontractor's ability
to control the environment on a multiemployer job site, stating:

. . . even if a trade contractor were to establish a regulated area,
it may not be able to limit access or operations by individuals
outside of its management or control, particularly in the absence of
a representative of a general contractor or construction manager
(Document ID 2187, p. 6).

    The Interlocking Concrete Pavement Institute indicated that other
construction trade workers labor in the same area from 10 to 90 percent
of the time, and that efforts by OSHA to restrict access among trades
on a job site would result in chaos (Document ID 2246, p. 11). The LBA
added that, although OSHA's proposed requirements might be suitable for
a single-employer setting where working conditions are somewhat
consistent, they were unworkable in the construction industry (Document
ID 2269, p. 8).
    OSHA received feedback from employee representatives and public
health advocates indicating support for a requirement that employers
establish and limit access to areas where high exposures may occur in
the construction industry (Document ID 2177, Attachment B, p. 14; 2371,
Attachment 1, pp. 17-19; 3589, Tr. 4263; 4223, p. 102). For example,
the Laborers Health and Safety Fund of North America argued that
regulated areas are helpful because they provide a visible indicator
that a hazardous area exists for employees in different trades who may
be on the worksite but would not otherwise be aware of the potential
for exposure to respirable crystalline silica in that area (Document ID
3589, Tr. 4263). NIOSH supported the need to protect workers on a
construction site from exposure via regulated areas and/or a written
access control plan. NIOSH also noted the importance of competent
persons and how they play an integral role in establishing regulated
areas (Document ID 2177, Attachment B, pp. 8-10, 14).
    Several commenters representing public health organizations and
unions opined that construction employers could implement regulated
areas on construction sites without a great deal of difficulty
(Document ID 3585, Tr. 3090-3091; 4234, Part 1, pp. 24-25). The
American Industrial Hygiene Association (AIHA) suggested how an
employer might determine whether a regulated area needs to be
established:

    Utilization of the Table 1 as a compliance option when
respirators are required means the surrounding area must be
considered a regulated area or under an access control plan. This
combined with the engineering controls can help address the common
problem of adjacent workers being inadvertently exposed to silica
particulates. The need for a regulated area or control plan would
now be an objective determination by the competent person. This in
turn would help identify workers or areas where inadvertent exposure
may occur and consequently allow procedures to be implemented to
prevent this (Document ID 2169, p. 4).

    Other commenters indicated that, to an extent, regulated areas
already exist on construction sites. At the public hearings, the Mason
Contractors Association of America provided testimony pointing out that
a vast majority of masonry work is already carried out in restricted
zones, and that access to these zones by other workers is limited. They
noted that access to these restricted work zones was ultimately
controlled by the general contractor (Document ID 3585, pp. 2933-2934).
BCTD noted that Kevin Turner of Hunt Construction Group, testifying on
behalf of CISC, indicated that contractors creating a hazard on
construction worksites identify their work areas to avoid putting other
workers at risk, and explained how different contractors on a multi-
employer site routinely establish exclusion zones to exclude other
workers from hazardous areas. BCTD argued that there is no reason why
such an approach would not work for areas with high silica exposure as
well (Document ID 4223, p. 102-105). ASSE indicated that, while the
organization recognized the potential value of establishing regulated
areas where silica overexposures are anticipated, there may be valid,
practical reasons for exempting short-term construction worksites from
this requirement as long as alternative worker protections are in place
(Document ID 3430, p. 3)
    After a review of these comments submitted on the proposed rule by
construction industry stakeholders, OSHA concludes that a requirement
for regulated areas is not appropriate for the construction standard.
OSHA proposed to require regulated areas wherever an employee's
exposure to respirable crystalline silica is, or can reasonably be
expected to be, in excess of the PEL. However, OSHA expects that a
majority of the regulated community in construction will implement the
specified exposure control methods presented in paragraph (c) of the
standard for construction (i.e., the controls listed in Table 1) for
the purposes of reducing occupational exposure to respirable
crystalline silica and to assure compliance with the standard.
Employers who implement the specified exposure control methods
presented in paragraph (c) of the standard for construction will not be
required to assess employee exposures to respirable crystalline silica,
and thus will not necessarily be aware of situations where employee
exposures exceed the PEL. Furthermore, these employers who are not
necessarily required to conduct an exposure assessment would thereby
not have the data necessary to establish and demarcate the boundaries
of regulated areas (i.e., the point at which exposures no longer exceed
the PEL). Therefore,

most construction employers will not have an objective basis for
establishing regulated areas.
    In addition, OSHA basis its decision not to require regulated areas
in the standard for construction in part on its recognition that
conditions at construction worksites present challenges to establishing
regulated areas for respirable crystalline silica exposure due to the
varied and changing nature of construction work. Various commenters
representing construction interests expressed how factors such as
environmental variability normally present in construction differ
substantially from those typically found in general industry and
maritime workplaces. These commenters noted that construction tasks are
often of relatively short duration; they are commonly performed
outdoors, sometimes under adverse environmental conditions; and they
are normally performed at non-fixed workstations or worksites. These
factors make establishment of regulated areas impractical for many
construction tasks. Silica-generating tasks in construction often
involve movement to different locations during the workday, and
respirable crystalline silica may be subject to changes in wind
currents, meaning that exposure patterns may frequently shift.
Accordingly, in the typical construction project involving silica-
generating tasks, it is difficult to determine appropriate boundaries
for regulated areas because the work and worksite are varied and
subject to environmental influences (e.g., Document ID 2246, p. 11;
2269, pp. 4, 9-10; 2289, pp. 6-7; 2309, p. 3; 2327, p. 20).
    OSHA finds the evidence of the particular and varying nature of
construction work persuasive. Furthermore, the requirement for a
competent person as part of the written exposure control plan
requirements in paragraph (g)(4) of the standard for construction
provides that a designated competent person on the worksite will have
the responsibility to restrict access to work areas, where necessary,
to limit exposures to respirable crystalline silica. OSHA concludes
that this requirement will achieve the primary objectives of a
regulated area.
    OSHA realizes that in some cases general industry work tasks and
work environments may be comparable to those found in construction.
Although no exceptions have been carved out of the requirement in the
standard for general industry and maritime, where the general industry
or maritime employer can show compliance is not feasible, regulated
areas will not have to be established insofar as infeasibility is a
complete defense to an OSHA citation. See United Steelworkers v.
Marshall, 647 F.2d 1189 (D.C. Cir. 1980); Marshall v. West Point
Pepperell, Inc., 588 F.2d 979 (5th Cir. 1979). As a general matter,
however, OSHA's longstanding distinction between general industry
(including, for these purposes, the maritime sector), on the one hand,
and the construction sector, on the other hand, provides an appropriate
line for delineating between those tasks where the employer generally
is reasonably able to establish regulated areas where exposures to
respirable crystalline silica exceed the PEL versus tasks where
regulated areas are generally not practicable.
    ASTM E 1132-06 and ASTM E 2625-09 do not include requirements for
regulated areas. However, both industry consensus standards indicate
that workers should not work in areas where visible dust is generated
from crystalline silica-containing materials without the use of
respiratory protection, unless proven protective measures are used or
sampling shows exposure is below the exposure limit (see Section
<IP_ADDRESS> in each standard) (Document ID 1466, p. 4; 1504, p. 3). OSHA
considers the approach taken in its standard for construction to be
consistent with the approach taken in the ASTM standards. OSHA further
considers that the requirement for regulated areas in the standard for
general industry and maritime better effectuates the purposes of the
OSH Act because the establishment of regulated areas in those
workplaces, where they are most effective, serves to limit the number
of employees exposed and the level of exposure of employees who would
otherwise be at significant risk of suffering adverse health effects
from exposure to respirable crystalline silica. As explained above,
regulated areas make employees aware of the presence of respirable
crystalline silica at levels above the PEL and the need for protective
measures, and serve to limit respirable crystalline silica exposure to
as few employees as possible. Additionally, OSHA notes that the
industry consensus standards addressing occupational exposure to
respirable crystalline silica do not include requirements for
protective clothing. The OSHA rule is consistent with the consensus
standards in this respect also.

Methods of Compliance

    Paragraph (f)(1) of the standard for general industry and maritime
(paragraph (d)(3)(i) of the standard for construction) establishes a
hierarchy of controls that employers must use to reduce and maintain
exposures to respirable crystalline silica to or below the permissible
exposure limit (PEL) of 50 [mu]g/m\3\. The rule requires employers to
implement engineering and work practice controls as the primary means
to reduce exposure to the PEL or to the lowest feasible level above the
PEL. In situations where engineering and work practice controls are not
sufficient to reduce exposures to or below the PEL, employers are
required to supplement these controls with respiratory protection,
according to the requirements of paragraph (g) of the standard for
general industry and maritime (paragraph (e) of the standard for
construction).
    OSHA's long-standing hierarchy of controls policy was supported by
many commenters including the National Institute for Occupational
Safety and Health (NIOSH), the American Society of Safety Engineers
(ASSE), the American Industrial Hygiene Association, the American
Federation of Labor and Congress of Industrial Organizations (AFL-CIO),
the American Public Health Association (APHA), the National Asphalt
Pavement Association (NAPA), the National Utility Contractors
Association, the American Road and Transportation Builders Association
(ARTBA), and the International Safety Equipment Association (ISEA)
(e.g., Document ID 1757, p. 4; 1771, p. 1; 1797, p. 5; 1800, p. 5;
2106, p. 2; 2166, p. 3; 2173, p. 4; 2178, Attachment 1, pp. 3-4; 2181,
p. 9; 2240, p. 2; 2256, Attachment 2, pp. 11-12; 2278, p. 3; 2313, p.
6; 2315, p. 3; 2329, p. 5; 2336, p. 7; 2371, Attachment 1, p. 22; 2373,
pp. 3-4; ; 3468, p. 3; 3516, p. 3; 3577, Tr. 791; 3578, Tr. 1044-1045;
3579, Tr. 182-183; 3581, Tr. 1564, 1648-1651; 3583, Tr.2237, 2243-2244,
2451, 2456; 3584, Tr. 2576-2577; 3955, Attachment 1, p. 2; 3585, Tr.
3112; 3586, Tr. 3162, 3200; 3589, Tr. 4147; 1759; 4203, p. 4; 4204, pp.
64-65; 4219, pp. 16, 20; 4223, p. 86; 4227, p. 1; 4233, Attachment 1,
p. 14; 4235, p. 14). Tom Ward, a bricklayer and member of the
International Union of Bricklayers and Allied Craftworkers (BAC)
testified:

    [The hierarchy of controls] is the first thing we are supposed
to do. Whenever feasible, eliminate the hazard. PPE is and always
should be the last line of defense. Switching it is going backwards
. . . (Document ID 3585, Tr. 3070).

    Many industry commenters, including trade associations, generally
objected to OSHA's proposed application of the hierarchy of controls in
the rule. These commenters included the U.S. Chamber of Commerce (the
Chamber), Associated

Builders and Contractors, the Association of American Railroads (AAR),
Battery Council International (BCI), the Motor and Equipment
Manufacturers Association (MEMA), the Institute of Makers of Explosives
(IME), the Association of Energy Service Companies, and the Precast/
Prestressed Concrete Institute (PCI) (e.g., Document ID 1728; 1992, pp.
10-11; 2102, p. 2; 2130, pp. 1-2; 2151, p. 1; 2211, pp. 6-7; 2213, pp.
3-4; 2276, p. 3; 2288, pp. 12-13;2289, p. 7; 2325, p. 2; 2326, p. 2;
2344, p. 2; 2361, p. 3; 2366, p. 5; 4194, pp. 12-13). These commenters
asked OSHA to reconsider its preference for engineering and work
practice controls and permit the use of respiratory protection, such as
powered air-purifying respirators (PAPRs), instead of engineering and
work practice controls to reduce exposures to respirable crystalline
silica to or below the PEL. For example, the Chamber urged OSHA to
support

. . . new technology and policies favoring effective, comfortable,
respirators and clean filtered air helmets, which provide full
protection but are not favored by OSHA's outdated `hierarchy of
control' policy (Document ID 4194, p. 4).

Similarly, the American Foundry Society (AFS) argued that:

    OSHA's preference for controls other than respirators is based
on a policy that was adopted decades ago, and fails to take into
account changes in respirator technology that have resulted in
improved performance, improved reliability, improved worker
acceptance, and increased protection (Document ID 3487, p. 25).

Greg Sirianni, an industrial hygienist testifying for the Chamber,
commented that some respiratory protection, such as PAPRs, ``should not
be looked at as mere respirators, but as microenvironmental engineering
controls'' (Document ID 2364, p. 12). He described several studies
demonstrating the effectiveness of PAPRs with helmets/hoods (Document
ID 2364, pp. 6-7). He also referenced studies showing that PAPRs reduce
physiological burdens, as well as provide increased comfort, ease of
use, and improved communication, when compared to traditional air-
purifying respirators (Document ID 2364, pp. 8-10). Other industry
commenters, including the National Association of Manufacturers (NAM),
AFS, and National Mining Association, echoed Mr. Sirianni's conclusion
about the effectiveness of PAPRs (Document ID 2211, pp. 6-7; 2379,
Appendix 1, p. 49; 2380, Attachment 2, pp. 22-23; 3489, p. 5;). Peter
Mark, Corporate Director of Safety, Health, and Environment at Grede
Holdings, testified that some respirators, such as air-supplied
helmets, can also provide eye and face protection (Document ID 3584,
Tr. 2685-2686). The George Washington University Regulatory Studies
Center argued that OSHA's hierarchy of controls eliminates the
incentive to develop more effective, lower cost, and more comfortable
respirators and ``distorts the development of new knowledge that could
provide superior protection for employees'' (Document ID 1831, p. 15).
    Other commenters pointed to the disadvantages of engineering
controls. The Construction Industry Safety Coalition (CISC), NAM, PCI,
and AFS noted that engineering controls are subject to human error and
maintenance concerns (Document ID 2319, p. 95; 2380, Attachment 2, p.
22; 3487, p. 25; 3581, Tr. 1738, 1762; 3589, Tr. 4357). The Tile
Roofing Institute (TRI), National Roofing Contractors Association
(NRCA), National Association of Home Builders (NAHB), CISC, and NAM
described situations where the use of engineering and work practice
controls could present other hazards, such as falls (Document ID 2191,
pp. 9-10; 2214, pp. 3-4; 2296, p. 28; 2319, p. 93; 3587, Tr. 3593-3594;
4225, p. 2; 4226, p. 3). OSCO Industries (OSCO) commented that where
ventilation requires all doors and windows to be closed, engineering
controls can put physiological and psychological strain on employees
(Document ID 1992, p. 10).
    NIOSH provided evidence that recent improvements in PAPRs have not
eliminated all of their disadvantages. NIOSH cited several studies
suggesting that psychological issues, medical disqualifications,
communication impairment, hearing degradation, and visual impairment
remained even for PAPRs (Document ID 4233, Attachment 1, pp. 17-20).
NIOSH also noted that there are no maximum weight requirements for
PAPRs, some of which can be fairly heavy (Document ID 4233, Attachment
1, p. 18). When questioned about the use of PAPRs in the brick
industry, Thomas Brown, the Director of Health and Safety at Acme Brick
Company, testified that:

    No, we have not used [PAPRs]. And the reason why [is] it would
be almost virtually impossible to wear those type[s] of respirators
and perform the tasks that they are doing (Document ID 3577, Tr.
752).

    No commenter representing employees or public health organizations
agreed that PAPRs have improved to the point that they have become
preferable to engineering controls. For example, when asked whether
PAPRs should be viewed as an alternative to engineering controls and
treated on the same level in the hierarchy of controls, Frank Hearl,
Chief of Staff at NIOSH, testified that, ``. . . in terms of the PAPR
and other respirators, it all sort of falls into the hierarchy of
controls and suffers the same problems as the other respirators in that
it doesn't control the entire environment'' (Document ID 3579, Tr.
233). The Building and Construction Trades Department, AFL-CIO (BCTD)
testified that PAPRs are not an adequate alternative given that they do
not ``. . . control the hazards at the source for all workers''
(Document ID 3581, Tr. 1668-1669). Similarly, ISEA commented that ``. .
. the association does not believe PAPRs can be used as engineering
controls'' since they do not remove hazards from the workplace
(Document ID 4227, p. 1).
    NIOSH, public health organizations, labor unions, individual
employees, trade associations, public interest organizations and
employers also provided additional evidence of the discomfort and
difficulties experienced by employees who wear respirators (e.g.,
extreme temperatures, visibility restrictions, communication
impairment, psychological issues, strain on respiratory and cardiac
systems) (Document ID 1758; 2116, Attachment 1, p. 28; 2178, Attachment
1, p. 4; 2181, pp. 9, 12; 2262, p. 26; 2314, p. 2; 2373, p. 4; 3571,
Attachment 1, p. 2; 3577, Tr. 839-841; 3579, Tr. 183-184; 3580, Tr.
1526-1527; 3582, Tr. 1872-1874, 1897, 1899-1901; 3583, Tr. 2434-2435;
3585, Tr. 3112; 3586, Tr. 3174-3175, 3180, 3250, 3252-3253; 3587, Tr.
3583-3584, 3637-3638; 4233, Attachment 1, pp. 18-19; 4235, p. 12).
Other commenters, including NIOSH, the International Union of Operating
Engineers (IUOE), the Brick Industry Association, TRI, NAPA, ARTBA, the
Interlocking Concrete Pavement Institute, Black Roofing, the National
Tile Contractors Association, Acme Brick, and iQ Power Tools also
described how respirator use can exacerbate various safety and health
threats to employees, such as trips, falls, ``struck by'' hazards, saw
hazards, and heat stress (Document ID 2262, p. 25; 2293; 3529, p. 2;
3577, Tr. 714, 750-752; 3583, Tr. 2170, 2237, 2372, 2435-2437; 3586,
Tr. 3341, 3406; 3587, Tr. 3583-3584, 3594; 3589, Tr. 4373; 4225, p. 6;
4233, Attachment 1, p. 18; 4234, Part 1 and Part 2, pp. 30-31; 4235, p.
12). IUOE, the Laborers' Health and Safety Fund of North America
(LHSFNA), and Arch Masonry further noted that reliance on respirators
to protect

employees from exposures to respirable crystalline silica could end the
careers of employees who cannot pass the medical evaluation, but can do
the work (Document ID 2262, p. 27; 2292, p. 4; 3587, Tr. 3656-3567;
3589, Tr. 4274-4275).
    In addition, NIOSH and other public health professionals described
how respirators are more prone to misuse or other human error, as they
depend on human behavior to achieve beneficial results (Document ID
2374, Attachment 1, pp. 5-6; 3577, Tr. 848-849; 3579, Tr. 183-184). On
the other hand, engineering controls are easier to monitor and
maintain. As Dr. Celeste Monforton testified:

    It is illogical to suggest that diligently meeting all the
laborious requirements necessary for an effective respiratory
protection program for a whole crew of employees is easier than
ensuring that a handful of silica-generating pieces of equipment are
maintained (Document ID 3577, Tr. 849).

    Various individuals and organizations detailed the lack of adequate
fit testing and respiratory protection programs in practice, which can
significantly impact respirator effectiveness. These included Dr.
Monforton, ASSE, the National Council of La Raza, the National
Consumers League (NCL), APHA, the National Council for Occupational
Safety and Health, NRCA, and Arch Masonry as well as workers, including
James Schultz and Allen Schultz (Document ID 2166, p. 3; 2173, p. 5;
2178, Attachment 1, pp. 3-4; 2373, pp. 3-4; 3577, Tr. 848-849; 3578,
Tr. 1040-1041, 1042-1043; 3586, Tr. 3161, 3213-3214, 3236-3237, 3253-
3254; 3587, Tr. 3625, 3680-3681; 3955, Attachment 1, p. 2). Workers,
including James Schultz, Jonass Mendoza, Santiago Hernandez, Juan Ruiz,
Norlan Trejo and Jose Granados described their negative experiences
with respirator use, including the lack of fit testing, training, and
proper maintenance (Document ID 3571, Attachment 2, p. 3; 3571,
Attachment 3, p. 2; 3571, Attachment 5, p. 1; 3571, Attachment 7, p. 1;
3583, Tr. 2487; 3586, Tr. 3201-3202;). Dr. Laura Welch, representing
BCTD, testified that in her experience, respiratory protection does not
prevent employees from developing lung disease, but that engineering
controls are effective (Document ID 3581, Tr. 1648-1649).
    Further, NIOSH, labor organizations (e.g., LHSFNA, the
International Association of Sheet Metal, Air, and Rail Transportation
Workers, the Operative Plasterers' and Cement Masons' International
Association, the International Union of Painters and Allied Trades
(IUPAT), the United Union of Roofers, Waterproofers, and Allied
Workers, BAC, the United Steelworkers, BCTD, and AFL-CIO), public
health organizations (e.g., APHA), public interest organizations (e.g.,
the Center for Biological Diversity, the Center for Effective
Government, and NCL), and individual workers described how limiting
exposure to respirable crystalline silica at its source through
engineering and work practice controls best protects employees involved
in dust-generating operations, as well as other employees and the
public from these exposures (e.g., Document ID 2178, Attachment 1, p.
4; 2253, pp. 1-2; 2329, p. 4; 2373, p. 4; 2374, Attachment 1, pp. 5-6;
3516, p. 3; 3579, Tr. 184-185, 233; 3581, Tr. 1590, 1593-1594, 1649-
1651,1669, 1708-1709; 3582, Tr. 1878-1879, 1881-1883; 3583, Tr. 2455-
2456; 3584, Tr. 2578-2579; 3585, Tr. 3067-3069; 4204, pp. 68, 72-74;
3589, Tr. 4232-4233; 4223, pp. 86-87; 4233, Attachment 1, pp. 11-14).
For example, LHSFNA noted that using controls on jackhammers, chipping
guns, hand-held grinders, and drywall sanders can reduce exposures to
nearby laborers (Document ID 2253, pp. 1-2). Norlan Trejo testified
that when cutting ceramic and granite, wet cutting helps protect both
the employee and bystanders (Document ID 3583, Tr. 2455-2456). Sean
Barrett, a terrazzo worker, testified that grinding floors in the
terrazzo industry exposes everyone on the worksite if controls are not
used:

    Every other trade has to walk through the cloud [of dust] to get
in and out of the building to use the outhouses or to go to the
coffee truck or even go home at the end of the day . . . [T]hey have
no choice but to walk through the dust (Document ID 3585, Tr. 3068).

Additionally, James Schultz, a former foundry employee from the
Wisconsin Coalition for Occupational Safety and Health, provided
testimony about how the lack of engineering controls creates dusty
conditions that can lead to other hazards. He described how dusty
conditions in a foundry led to incidents where employees were struck by
forklifts (Document ID 3586, Tr. 3242-3243).
    Some of the same industry commenters advocating for the use of
PAPRs in place of engineering controls have acknowledged the importance
of engineering controls to protect employees from exposures to
respirable crystalline silica. For example, AFS, in its Guide for
Selection and Use of Personal Protective Equipment and Special Clothing
for Metalcasting Operations, describes the hierarchy of controls as the
basis for choosing strategies for protecting employers from exposures
to airborne contaminants. The guide concludes that air-supplied hoods
and PAPRs are important options when choosing respiratory or personal
protection, but does not support using these in lieu of engineering
controls (Document ID 2379, Appendix 6). NAM noted that they were not
opposed to using engineering controls where they are feasible and
effective (Document ID 3581, Tr. 1753). Greg Sirianni, an expert for
the Chamber, testified that:

. . . there are obviously benefits to engineering controls, and by
all means I want the use of engineering controls when they are
possible. And in certain work environments . . . you need to have
something that can protect all workers in all scenarios, and
engineering controls are good for most cases, but there are a lot of
workers out there that need [PAPRs], and I really recommend their
use (Document ID 3578, Tr. 1104-1105).

Other industry groups provided additional evidence that the hierarchy
of controls is embraced and applied in practice. For example, Wayne
D'Angelo of the American Petroleum Institute (API) testified that the
organization supports the traditional use of the hierarchy of controls
to protect employees (Document ID 3589, Tr. 4065). The National
Industrial Sand Association (NISA) has built the hierarchy of controls
into its Practical Guide to an Occupational Health Program for
Respirable Crystalline Silica (Document ID 1965, Attachment 2, pp. vii,
44). The National Stone, Sand, and Gravel Association's occupational
health program, which is based on NISA's program, also supports the
industrial hygiene hierarchy of controls (Document ID 3583, Tr. 2312).
    OSHA concludes that requiring primary reliance on engineering
controls and work practices is necessary and appropriate because
reliance on these methods is consistent with good industrial hygiene
practice, and with the Agency's experience in ensuring that employees
have a healthy workplace. The Agency finds that engineering controls:
(1) Control crystalline silica-containing dust particles at the source;
(2) are reliable, predictable, and provide consistent levels of
protection to a large number of employees; (3) can be monitored
continually and relatively easily; and (4) are not as susceptible to
human error as is the use of personal protective equipment. The use of
engineering controls to prevent the release of silica-containing dust
particles at the source also minimizes the silica exposure of other
employees in surrounding work areas who are not directly involved in
the task that is generating the dust, and

may not be wearing respirators. This issue of secondary exposures to
other laborers and bystanders is especially of concern at construction
sites (e.g., Document ID 2177, Attachment B, pp. 14-15; 2329, p. 4;
2319, p. 28, 3581, Tr. 1587-1588).
    Under the hierarchy of controls, respirators can be another
effective means of protecting employees from exposure to air
contaminants. 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 one of
these conditions can reduce or eliminate the protection the respirator
provides to some or all of the employees. For example, certain types of
respirators require the user to be clean shaven to achieve an effective
seal where the respirator contacts the employee's skin. Failure to
ensure a tight seal due to the presence of facial hair compromises the
effectiveness of the respirator.
    Respirator effectiveness ultimately relies on the good work
practices of individual employees. In contrast, the effectiveness of
engineering controls does not rely so heavily on actions of individual
employees. Engineering and work practice controls are capable of
reducing or eliminating a hazard from a worksite, 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 continues to consider 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 olfactory 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 employees 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
cardiovascular and respiratory diseases (e.g., a history of high blood
pressure, angina, heart attack, cardiac arrhythmias, stroke, asthma,
chronic bronchitis, emphysema), reduced pulmonary function caused by
other factors (e.g., smoking or prior exposure to respiratory hazards),
neurological or musculoskeletal disorders (e.g., epilepsy, lower back
pain), and impaired sensory function (e.g., a perforated ear drum,
reduced olfactory function). Psychological conditions, such as
claustrophobia, can also impair the effective use of respirators by
employees and may also cause, independent of physiological burdens,
significant elevations in heart rate, blood pressure, and respiratory
rate that can jeopardize the health of employees who are at high risk
for cardiopulmonary disease (see 63 FR 1152, 1208-1209 (1/8/98)).
    In addition, safety problems created by respirators that limit
vision and communication must always be considered. In some difficult
or dangerous jobs, effective vision or communication is vital. Voice
transmission through a respirator can be difficult, annoying, and
fatiguing. In addition, movement of the jaw in speaking can cause
leakage, thereby reducing the efficiency of the respirator and
decreasing the protection afforded the employee. Skin irritation can
result from wearing a respirator in hot, humid conditions. Such
irritation can cause considerable distress to employees and can cause
employees to refrain from wearing the respirator, thereby rendering it
ineffective.
    These potential burdens placed on employees by the use of
respirators were acknowledged in OSHA's revision of its respiratory
protection standard, and are the basis for the requirement (29 CFR
1910.134(e)) that employers provide a medical evaluation to determine
the employee's ability to wear a respirator before the employee is fit
tested or required to use a respirator in the workplace (see 63 FR at
1152). Although experience in industry shows that most healthy
employees do not have physiological problems wearing properly chosen
and fitted respirators, nonetheless common health problems can cause
difficulty in breathing while an employee is wearing a respirator.
    While OSHA acknowledges that certain types of respirators, such as
PAPRs, may lessen problems associated with breathing resistance and
skin discomfort, they do not eliminate them. OSHA concludes that
respirators do not provide employees with a level of protection that is
equivalent to engineering controls, regardless of the type of
respirator used. It is well-recognized that certain types of
respirators are superior to other types of respirators with regard to
the level of protection offered, or impart other advantages like
greater comfort. OSHA has evaluated the level of protection provided by
different types of respirators in the Agency's Assigned Protection
Factors rulemaking (68 FR 34036 (06/06/03)). Even in situations where
engineering controls are not sufficiently effective to reduce exposure
levels to or below the PEL, the reduction in exposure levels benefits
employees by reducing the required protection factor of the respirator,
which provides a wider range of options in the type of respirators that
can be used. For example, for situations in which dust concentrations
are reduced through use of engineering controls to levels that are less
than ten times the PEL, employers would have the option of providing
approved half-mask respirators with an assigned protection factor (APF)
of 10 that may be lighter and easier to use when compared with full-
facepiece respirators.
    All OSHA substance-specific health standards have recognized and
required employers to observe the hierarchy of controls, favoring
engineering and work practice controls over respirators. OSHA's PELs,
including the previous PELs for respirable crystalline silica, also
incorporate this hierarchy of controls. The Agency's adherence to the
hierarchy of controls has been successfully upheld by the courts (see
Section II, Pertinent Legal Authority for further discussion of these
cases). In addition, the industry consensus standards for crystalline
silica (ASTM E 1132-06, Standard Practice for Health Requirements
Relating to Occupational Exposure to Respirable Crystalline Silica, and
ASTM E 2625-09, Standard Practice for Controlling Occupational Exposure
to Respirable Crystalline Silica for Construction and Demolition
Activities) incorporate the hierarchy of controls. NRCA also pointed
out that the ANSI Z10, Standard for Occupational Health and Safety
Management Systems, supports the hierarchy of controls (Document ID
2214, p. 3) and Dr. Celeste Monforton noted that the

hierarchy of controls has been followed and adopted by safety and
health regulatory agencies around the world, including Safe Work
Australia, the country's tripartite health and safety body, and the
Canadian Province of Ontario's Health and Safety Agency (Document ID
3577, Tr. 847-848).
    As explained in Section II, Pertinent Legal Authority, the very
concept of technological feasibility for OSHA standards is grounded in
the hierarchy of controls. The courts have clarified that a standard is
technologically feasible if OSHA proves a reasonable possibility,

. . . within the limits of the best available evidence . . . 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 (United Steelworkers v. Marshall, 647 F.2d 1189, 1272
(D.C. Cir. 1980)).

Allowing use of respirators instead of engineering and work practice
controls would be a significant departure from this framework for
evaluating the technological feasibility of a PEL.
    While labor groups were opposed to any exemptions from the
hierarchy of controls (Document ID 3586, Tr. 3235-3237), industry
commenters, including both individual employers and trade associations,
urged OSHA to consider making exemptions to the hierarchy in various
situations. Commenters, including the Edison Electric Institute (EEI),
Dal-Tile, the Glass Association of North America (GANA), the Tile
Council of North America, the Non-Ferrous Founders' Society (NFFS),
PCI, and the Chamber, argued that employers need flexibility to
determine when enough engineering controls have been added and when
respirators can be used (Document ID 2147, p. 3; 2215, p. 6; 2276, p.
6; 2357, pp. 25-26; 2363, p. 4; 3491, p. 4; 3576, Tr. 466; 3589, Tr.
4364). NAM echoed this, arguing that employers will never know when or
if they are in compliance with the requirement to incorporate all
feasible engineering and work practice controls and the Agency should
thus base its requirements on objective criteria, while allowing
flexibility to achieve compliance (Document ID 3581, Tr. 1738). Lapp
Insulators, the Indiana Manufacturing Association, Murray Energy
Corporation, BCI, Rheem Manufacturing Company, MEMA, IME, CISC, AFS,
NFFS, and NAM urged OSHA to permit the use of respirators to satisfy
the obligation to control exposures where feasible engineering and work
practice controls are insufficient to bring exposure levels to or below
the PEL (Document ID 1801, pp. 3-4; 2102, p. 2; 2130, pp. 1-2; 2151, p.
1; 2213, pp. 3-4; 2319, p. 95; 2325, p. 2; 2326, p. 2; 2361, p. 3;
2380, Appendix 2, pp. 22-23; 3486, p. 2; 3491, pp. 4-5; 3581, Tr. 1752-
1753; 4226, p. 2). This concern was echoed by other commenters who
encouraged OSHA to permit the use of respirators in industries using
large amounts of crystalline silica (e.g., oil and gas operations where
hydraulic fracturing is conducted), where engineering controls alone
would not be likely to reduce exposures to or below the PEL (Document
ID 2283, p. 3; 3578, Tr. 1090-1091).
    OSHA disagrees. Instead, the Agency considers engineering controls
to be the most effective method of protecting employees and allows
respiratory protection only after all feasible engineering controls and
work practices have been implemented or where such controls have been
found infeasible. If an employer has adopted all feasible engineering
controls, and no other feasible engineering controls are available, the
rule would permit the use of respirators. On the other hand, if
feasible engineering controls are available that would reduce
respirable crystalline silica exposures that exceed the PEL, then these
controls are required. Thus, OSHA has concluded these engineering
controls better protect employees.
    Commenters, including CISC and OSCO, urged OSHA to permit the use
of respirators for short duration, intermittent, or non-routine tasks
(Document ID 1992, pp. 3, 5; 2319, pp. 95, 115; 3580, Tr. 1463-1464).
Others, such as the Glass Packaging Institute (GPI) and NAM, argued
that OSHA should permit the use of respirators for maintenance
activities (Document ID 2290, pp. 2, 3; 2380, Attachment 2, pp. 14-15;
3493, pp. 2-3). Verallia North America recommended that respirators be
allowed in all refractory repairs (Document ID 3584, Tr. 2848).
    Where OSHA requires respirator use in this rule, the requirement is
tied to expected or recorded exposures above the PEL, not categorically
to specific operations or tasks per se. The rule permits the use of
respirators where exposures exceed the PEL during tasks for which
engineering and work practice controls are not feasible. Some tasks,
such as certain maintenance and repair activities, may present a
situation where engineering and work practice controls are not
feasible. For example, GPI noted that respirators are needed to address
failures of any conveyance system (elevators, conveyors, or pipes),
failures of dust collecting bag systems, or section head failures at
glass plant facilities (Document ID 3493, p. 3). OSCO described how
engineering controls are not feasible for cupola (furnace) repair work
and baghouse maintenance activities (Document ID 1992, pp. 3, 5). The
Agency agrees that for tasks, such as certain maintenance and repair
activities, where engineering and work practice controls are not
feasible, the use of respirators is permitted.
    The Chamber and the American Subcontractors Association (ASA)
suggested that the hierarchy of controls is not appropriate for silica
exposures in construction workplaces (Document ID 2187, p. 6; 2283, p.
3). While ASSE generally supported the hierarchy of controls, it
acknowledged that there might be practical issues with implementation
on short-term construction worksites (Document ID 2339, p. 4). More
specifically, the Mason Contractors Association of America and Holes
Incorporated urged OSHA to consider the approach taken by the ASTM
standard for the construction industry (ASTM E 2625-09), which provides
an exception to the hierarchy for brief, intermittent silica generating
tasks of 90 minutes or less per day (Document ID 3580, Tr. 1453; 3585,
Tr. 2882). Conversely, BCTD argued that even for silica dust-generating
tasks of short duration where respiratory protection is employed, a
failure to employ engineering controls could result in dangerous
exposures (Document ID 4219, p. 17). They contended that:

    There is no evidence in the record that exposures of only 90
minutes a day pose a lower risk of harm, such that respirators would
provide sufficient protection. Moreover . . . the industry failed to
prove that it is infeasible--or even difficult--to use engineering
controls in most silica-generating tasks (Document ID 4223, p. 88).

    OSHA finds, as discussed above, that primary reliance on
respirators to protect employees is inappropriate when feasible
engineering and work practice controls are available. This is as true
for the construction industry, as it is for other industries with
respirable crystalline silica exposures. Even where employees are
conducting intermittent silica generating tasks for 90 minutes or less
per day, if the exposures are above the PEL and feasible engineering
and work practice controls are available, they must be applied.
Further, although an exemption for employees conducting silica
generating tasks for 90 minutes or less per day is included in the ASTM
standard for the construction industry, the standard also includes the
hierarchy of controls, as well as task-based methods of compliance
based on engineering and work practice controls

that are feasible and available for many construction tasks (ASTM E
2625-09). This approach is consistent with the specified exposure
control methods for construction in paragraph (c)(1) described in the
summary and explanation of Specified Exposure Control Methods. OSHA
concludes that requiring the use of all feasible engineering and work
practice controls in the construction industry, even for tasks of short
duration generating respirable crystalline silica, is reasonably
necessary and appropriate to protect employees from exposures to
respirable crystalline silica.
    AFS, NISA, GANA, EEI, the North American Insulation Manufacturers
Association (NAIMA), and the Asphalt Roofing Manufacturers Association
urged OSHA to consider allowing employers to use respirators to achieve
compliance for operations where exposures exceed the PEL for 30 days or
less per year (Document ID 4229, p. 11; 2195, pp. 7, 38-39; 2215, pp.
9-10; 2291, pp. 2, 18; 2348, Attachment 1, pp. 17, 26-28, 40; 2357, p.
26; 2379, Appendix 1, pp. 48, 68-69; 3487, pp. 22-23). Similarly, NAM
proposed that OSHA could establish a maximum number of days a year when
respirators can be used in place of engineering controls (Document ID
2380, Attachment 2, pp. 24-25).
    Many of the examples mentioned by the commenters supporting this
exemption described maintenance and repair activities, such as baghouse
cleaning and furnace rebuilds. As discussed above, some tasks, such as
certain maintenance and repair activities, may present a situation
where engineering and work practice controls are not feasible. OSHA
agrees that, for tasks of this nature where engineering and work
practice controls are not feasible, the use of respirators is
permitted. Permitting employers to use respirators instead of feasible
engineering and work practice controls for exposures occurring for 30
days or less per year does not best effectuate the purpose of the
rule--to protect employees from exposures to respirable crystalline
silica. Thus, the Agency concludes that the hierarchy of controls is
appropriate whenever feasible engineering and work practice controls
are available.
    The American Composite Manufacturers Association suggested that
small businesses be exempt from the hierarchy of controls (Document ID
3588, Tr. 3933-3936). Bret Smith urged OSHA to allow small entities to
use respiratory protection temporarily to allow time to prepare for the
costs of implementation (Document ID 2203). OSHA does not agree that
there should be a distinction between the protection employees receive
in a small business or a large business. Protecting the safety and
health of employees is part of doing business. Thus, exposures to
respirable crystalline silica above the PEL, wherever they occur, must
first be controlled using all feasible engineering and work practice
controls available, before turning to respiratory protection. For the
reasons previously discussed, implementing and maintaining a
comprehensive respiratory protection program is a considerable
undertaking for many employers, and likely even more so for small
businesses. If employers are unable to properly train and fit employees
and maintain the equipment, respirators will not effectively protect
employees from exposures to respirable crystalline silica.
    NAM proposed that OSHA adopt language to allow respirators to be
used when exposures are below a specified level:

    Where airborne exposures to RCS on a time-weighted-average basis
are below XX milligrams per cubic meter, employers may require the
use of respirators in accordance with the requirements of 1910.134.
Where exposures exceed this level, employers are required to adopt
engineering and administrative controls to reduce exposures
(Document ID 2380, Attachment 2, pp. 24-25).

They specifically provided the example of 5 mg/m\3\ (i.e., 5,000 [mu]g/
m\3\), the respirable dust PEL, which would permit the use of
respirators that provide a protection factor of 100 to achieve
compliance with the PEL of 50 [mu]g/m\3\.
    As discussed above, this approach is in conflict with the concept
of technological feasibility for OSHA standards. Technological
feasibility is determined based on the ability of a typical firm to
develop and install engineering controls and work practice controls
that can meet the PEL without regard to the use of respirators. The
approach advanced by NAM would permit the use of respirators to achieve
the PEL, even where exposures reached 100 times the PEL. If
technological feasibility were based solely on the ability of
respirators to meet the PEL, OSHA could determine that a much lower PEL
would indeed be feasible. Further, a failure of respiratory protection
in situations where exposures reach 100 times the PEL could result in
extremely dangerous exposures.
    Therefore, OSHA rejects the various comments recommending upsetting
the long-established hierarchy of controls. Because engineering and
work practice controls are capable of reducing or eliminating a hazard
from the workplace, while respirators protect only the employees who
are wearing them and depend on the selection and maintenance of the
respirator and the actions of employees, OSHA holds to the view that
engineering and work practice controls offer more reliable and
consistent protection to a greater number of employees, and are
therefore preferable to respiratory protection. Thus, the Agency
continues to conclude that engineering and work practice controls
provide a more protective first line of defense than respirators and
must be used first when feasible.
    Engineering controls. The engineering controls that are required by
the standard can be grouped into four categories: (1) Substitution; (2)
isolation; (3) ventilation; and (4) dust suppression. Depending on the
sources of crystalline silica dust and the operations conducted, a
combination of control methods may reduce silica exposure levels more
effectively than a single method.
    Substitution refers to the replacement of a toxic material with
another material that reduces or eliminates the harmful exposure. OSHA
considers substitution to be an ideal control measure if it replaces a
toxic material in the work environment with a non-toxic material, thus
eliminating the risk of adverse health effects.
    As indicated in Chapter IV of the Final Economic Analysis and Final
Regulatory Flexibility Analysis (FEA), employers use substitutes for
crystalline silica in a variety of operations. For example, some
employers use substitutes in abrasive blasting operations, repair and
replacement of refractory materials, operations performed in foundries,
and in the railroad transportation industry. Commenters, such as NIOSH,
John Adams, Vice President of the American Federation of Government
Employees Local 2778, Kyle Roberts, and the National Automobile Dealers
Association (NADA) also identified several situations where substitute
materials and products were available or used in place of silica-
containing products, including: The use of plastic curbs in place of
concrete curbs to repair a highway overpass; the use of materials
containing aluminum oxide instead of crystalline silica in dental labs;
the use of aluminum pellets instead of sand in hydraulic fracturing
operations; the availability of silica-free OEM and auto-refinish paint
systems; and the availability of silica-free body fillers and silica-
free abrasives for auto

body repair work (Document ID 1763, p. 2; 1800, p. 5; 2177, Attachment
B, pp. 37-38; 2358, p. 4).
    Commenters also identified many situations where no substitute
materials and products were available to replace silica-containing
materials and products. For example, Grede Holdings and AFS noted that
there were no substitutes for sand for most foundry applications
(Document ID 2298, p. 2; 2379, Appendix 1, pp. 14-16; 3486, p. 4). The
General Contractors Association of New York, ASA, CISC, and NAHB noted
that the construction industry cannot select alternate materials to
avoid silica exposure, since nearly all construction materials and
products contain silica (Document ID 2187, p. 6; 2314, pp. 1-2; 2296,
pp. 7, 35; 2319, pp. 93-34). AAR and the American Short Line and
Regional Railroad Association noted that substitute ballast materials
with lower silica content cannot be used because they introduce safety
hazards for employees and the public (Document ID 2366, pp. 5-6). GANA
and NAIMA noted that silica is indispensable to the flat glass industry
(Document ID 2215, p. 5; 2348, Attachment 1, pp. 8-10). NAM noted that
viable alternatives of lower silica content are not available for some
products made by their members (Document ID 3581, Tr. 1728). The
Porcelain Enamel Institute noted that there are no proven replacements
for mill-added crystalline silica for wet-applied enamel systems, given
that the technical advantages offered by silica cannot be practically
and economically achieved with other materials (Document ID 2281, p.
3).
    The American College of Occupational and Environmental Medicine
(ACOEM), the Mount Sinai-Irving J. Selikoff Centers for Occupational
and Environmental Medicine, and Samantha Gouveia urged OSHA to more
explicitly encourage the use of substitution where feasible (Document
ID 1771, p. 1; 2080, pp. 4-5; 2208).
    Commenters also expressed concerns about the safety of substitutes
(Document ID 2080, pp. 4-5; 2187, p. 6; 2278, pp. 3-4). ACOEM suggested
that OSHA only endorse the use of substitutes when they have been
demonstrated to be safe in short- and long-term inhalation toxicology
studies and urged OSHA to request that NIOSH conduct a periodic
assessment that evaluates substitutes to determine which ones have been
found to be safe based upon results of inhalation toxicity and
epidemiologic studies (Document ID 2080, pp. 4-5). Dr. George
Gruetzmacher, an industrial hygiene engineer, urged OSHA to encourage
the use of alternative materials to silica when feasible, but only when
the substitute has been demonstrated to be safe in short- and long-term
inhalation toxicology studies or to prohibit the substitution of
materials which have not been demonstrated to be less toxic by
inhalation (Document ID 2278, pp. 3-4).
    While OSHA finds that substitution can be an ideal control measure
in certain circumstances, the Agency recognizes that this approach may
not be feasible or safer in many others. Because some alternatives to
silica or silica-containing materials may present health risks, OSHA is
not implying that any particular alternative is an appropriate or safe
substitute for silica. In its technological feasibility analyses, the
Agency identified information about situations where substitution may
be an available control strategy. OSHA strongly encourages employers to
thoroughly evaluate potential alternatives, where available, to
determine if a substitute can mitigate employees' exposure to
respirable crystalline silica without posing a greater or new
significant hazard to employees. Additionally, when substituting,
employers must comply with Section 5(a)(1) of the OSH Act (29 U.S.C.
654(a)(1)), which prohibits occupational exposure to ``recognized
hazards that are causing or are likely to cause death or serious
physical harm,'' and with applicable occupational safety and health
standards. For example, with respect to chemical hazards, OSHA's hazard
communication standard imposes specific requirements for employee
training, safety data sheets, and labeling (see 29 CFR 1910.1200).
    Isolation, i.e., separating workers from the source of the hazard,
is another effective engineering control employed to reduce exposures
to crystalline silica. Isolation can be accomplished by either
containing the hazard or isolating workers from the source of the
hazard. For example, to contain the hazard, an employer might install a
physical barrier around the source of exposure to contain a toxic
substance within the barrier. Isolating the source of a hazard within
an enclosure restricts respirable dust from spreading throughout a
workplace and exposing employees who are not directly involved in dust-
generating operations. Or, alternatively, an employer might isolate
employees from the hazard source by placing them in a properly
ventilated cab or at some distance from the source of the respirable
crystalline silica exposure.
    Ventilation is another engineering control method used to minimize
airborne concentrations of a contaminant by supplying or exhausting
air. Two types of systems are commonly used: Local exhaust ventilation
(LEV) and dilution ventilation. LEV is used to remove an air
contaminant by capturing it at or near the source of emission, before
the contaminant spreads throughout the workplace. Dilution ventilation
allows the contaminant to spread over the work area but dilutes it by
circulating large quantities of air into and out of the area.
Consistent with past recommendations such as those included in the
chromium (VI) standard, OSHA prefers the use of LEV systems to control
airborne toxics because, if designed properly, they efficiently remove
contaminants and provide for cleaner and safer work environments.
    Dust suppression methods are generally effective in controlling
respirable crystalline silica dust, and they can be applied to many
different operations such as material handling, rock crushing, abrasive
blasting, and operation of heavy equipment (Document ID 1147). Dust
suppression can be accomplished by one of three systems: Wet dust
suppression, in which a liquid or foam is applied to the surface of the
dust-generating material; airborne capture, in which moisture is
dispensed into a dust cloud, collides with particles, and causes them
to drop from the air; and stabilization, which holds down dust
particles by physical or chemical means (lignosulfonate, calcium
chloride, and magnesium chloride are examples of stabilizers).
    The most common dust suppression controls are wet methods (see
Chapter IV of the FEA). Water is generally an inexpensive and readily
available resource and has been proven an efficient engineering control
method to reduce exposures to airborne crystalline silica-containing
dust. Dust, when wet, is less able to become or remain airborne.
    Work practice controls. Work practice controls systematically
modify how employees perform an operation, and often involve employees'
use of engineering controls. For crystalline silica exposures, OSHA's
technological feasibility analysis shows that work practice controls
are generally applied complementary to engineering controls, to adjust
the way a task is performed (see Chapter IV of the FEA). For work
practice controls to be most effective, it is essential that employees
and supervisors are trained to be fully aware of the exposures
generated by relevant workplace activities and the impact of the
engineering controls installed. Work practice controls are preferred
over the use of personal protective equipment, since work practice
controls can address

the exposure of silica at the source of emissions, thus protecting
nearby employees.
    Work practice controls can also enhance the effects of engineering
controls. For example, to ensure that LEV is working effectively, an
employee would position the LEV equipment so that it captures the full
range of dust created, thus minimizing silica exposures. For many
operations, a combination of engineering and work practice controls
reduces silica exposure levels more effectively than a single control
method.
    The requirement to use engineering and work practice controls is
consistent with ASTM E 1132-06 and ASTM E 2625-09, the national
consensus standards for controlling occupational exposure to respirable
crystalline silica in general industry and in construction,
respectively. Each of these standards has explicit requirements for the
methods of compliance to be used to reduce exposures below exposure
limits. These voluntary standards specifically identify several
controls, which include use of properly designed engineering controls
such as ventilation or other dust suppression methods and enclosed
workstations such as control booths and equipment cabs; requirements
for maintenance and evaluation of engineering controls; and
implementation of certain work practices such as not working in areas
where visible dust is generated from respirable crystalline silica
containing materials without use of respiratory protection. For
employers in general industry and maritime, as well as those in
construction following paragraph (d) for tasks not listed in Table 1 or
where the employer does not fully and properly implement the
engineering controls, work practices, and respiratory protection
described in Table 1, OSHA similarly requires the use of engineering
and work practices controls to reduce employee exposures to or below
the PEL; however, this is a performance requirement and does not
specify any particular engineering and work practice controls that must
be implemented.
    Paragraph (f)(2)(i) of the standard for general industry and
maritime (paragraph (g)(1) of the standard for construction) requires
that employers establish and implement a written exposure control plan.
Paragraphs (f)(2)(i)(A)-(C) (paragraphs (g)(1)(i)-(iv) of the standard
for construction) specify the contents for written exposure control
plans. Paragraph (f)(2)(ii) (paragraph (g)(2) of the standard for
construction) specifies requirements for the employer to review the
plan at least annually and update it as needed. Paragraph (f)(2)(iii)
(paragraph (g)(3) of the standard for construction) requires the
employer to make the plan available to employees, employee
representatives, OSHA, and NIOSH. Details about the written exposure
control plan, including comments from stakeholders and OSHA's responses
to those comments, are included in the summary and explanation of
Written Exposure Control Plan.
    SECALs. In the NPRM, OSHA asked stakeholders to provide input as to
whether the Agency should establish separate engineering control air
limits (SECALs) for certain processes in selected industries. In OSHA's
cadmium standard (29 CFR 1910.1027 (f)(1)(ii), (iii), and (iv)), the
Agency established SECALs where compliance with the PEL by means of
engineering and work practice controls was infeasible. For these
industries, a SECAL was established at the lowest feasible level that
could be achieved by engineering and work practice controls. The PEL
was set at a lower level, and could be achieved by any allowable
combination of controls, including respiratory protection. A similar
exception was included in OSHA's chromium (VI) standard (29 CFR
1910.1026) for painting aircraft and large aircraft parts.
    OSHA received feedback from several commenters who supported
establishing SECALs (e.g., Document ID 2082, p. 8; 2379, Appendix 1, p.
61; 2380, Attachment 2, p. 23). For example, AFS argued for a SECAL of
150 or 200 [mu]g/m\3\ for foundries, with a PEL of 100 [mu]g/m\3\. AFS
indicated that many foundries now operate under a formal or informal
arrangement with OSHA that allows use of respirators as an acceptable
control to achieve compliance with the current PEL after implementing
all feasible engineering controls (Document ID 2379, Appendix 1, p.
61). ORCHSE Strategies stated that the use of SECALs could provide more
definitive expectations for employers based on the feasibility for
engineering controls in specific operations (Document ID 2277, p. 2).
The United Automobile, Aerospace and Agricultural Implement Workers of
America recommended that the PEL be even lower than OSHA proposed (25
[mu]g/m\3\), and suggested that SECALs could be established for those
industries for which 25 [mu]g/m\3\ is not feasible (Document ID 2282,
p. 16).
    Other commenters did not favor establishing SECALs. CISC stated
that it did not support the concept of SECALs, but that CISC would
continue to examine whether a SECAL was appropriate for the
construction industry (Document ID 2319, p. 128). NIOSH did not support
the use of SECALs and stated that the requirement to meet the PEL for
silica generating processes should be maintained (Document ID 2177,
Attachment B, p. 16).
    OSHA stresses that, where incorporated in a standard, a SECAL is
intended for application to discrete processes and operations within an
industry, rather than application to an entire industry, as some
supporters of SECALs seemed to suggest. For example, in OSHA's cadmium
standard, OSHA established SECALs for certain plating and other
processes in a few affected industries. OSHA did not receive evidence
to support establishing a SECAL for any discrete task or operation
within a particular industry in the respirable crystalline silica rule.
OSHA therefore has not established SECALs in the rule.
    Abrasive blasting. Abrasive blasting requirements remain the same
as proposed, except for minor editorial changes. Paragraph (f)(3) of
the standard for general industry and maritime (paragraph (d)(3)(ii) of
the standard for construction) requires the employer to comply with
paragraph (f)(1) of the standard for general industry and maritime
(paragraph (d)(3)(i) of the standard for construction) where abrasive
blasting is conducted using crystalline silica-containing blasting
agents, or where abrasive blasting is conducted on substrates that
contain crystalline silica. Thus, for abrasive blasting, employers must
follow the hierarchy of controls applicable to other tasks covered by
the rule.
    In this provision addressing abrasive blasting, the proposed
standard referred to ``where abrasive operations are conducted,'' but
for simplicity, this standard refers to ``where abrasive blasting is
conducted.'' OSHA intends this change to be editorial only, and does
not intend a substantive change from the proposed requirements.
    In addition, paragraph (f)(3) of the standard for general industry
and maritime indicates that the employer must comply with the
requirements of 29 CFR 1910.94 (Ventilation), 29 CFR 1915.34
(Mechanical paint removers) and 29 CFR 1915 Subpart I, as applicable,
where abrasive blasting is conducted using crystalline silica-
containing blasting agents, or where abrasive blasting is conducted on
substrates that contain crystalline silica. Paragraph (d)(3)(ii) of the
standard for construction indicates that the employer must comply with
the requirements of 29 CFR 1926.57 (Ventilation) in such circumstances.

    OSHA's general industry (29 CFR 1910.94) and construction
ventilation standards (29 CFR 1926.57), as well as the standards for
mechanical paint removers (29 CFR 1915.34) and personal protective
equipment for shipyard employment (29 CFR 1915 subpart I) provide
requirements for respiratory protection for abrasive blasting operators
and others involved in abrasive blasting. This rule includes cross-
references to these standards. Employers using abrasive blasting need
to consult these referenced standards to ensure that they comply with
their provisions for personal protective equipment and ventilation, and
other operation-specific safety requirements.
    ISEA urged OSHA to add a reference to the APF table at 29 CFR
1910.134(d)(3)(i)(A) in the general industry and construction standards
for ventilation, and to require that if the employer has no sampling
data to support the use of an abrasive blasting respirator with an APF
of 25, the employer must select a respirator with an APF of 1,000
(Document ID 2212, p. 1). The 3M Company similarly questioned the
respirator requirements under the ventilation standards, arguing that
without considering the performance (APF) of the respirator, some
employees could be overexposed to silica (Document ID 2313, pp. 1, 5-
6). Charles Gordon, a retired occupational safety and health attorney,
commented that even with the reference to the ventilation standards,
the provision is not protective enough. He encouraged the Agency to
require the most protective abrasive blasting hood and respirators and
require the best work practices (Document ID 2163, Attachment 1, p.
19).
    Given the high levels of hazardous dust generated during abrasive
blasting, OSHA has concluded, for reasons discussed in its
technological feasibility analyses for construction and for certain
general industry sectors like foundries and shipyards that perform
abrasive blasting in their operations, that respiratory protection will
continue to be necessary to reduce silica exposure below the PEL, even
with engineering and work practice controls in place (see the
discussion of abrasive blasting in Chapter IV of the FEA). This
standard also takes respirator use into account by cross-referencing
the specific respirator requirements already in place for abrasive
blasting. Employers are also required to comply with the requirements
of 29 CFR 1910.134 whenever respiratory protection is required by this
section. Under 29 CFR 1910.134, the employer is required to select and
provide an appropriate respirator based on the respiratory hazards to
which the employee is exposed and is required to use the APF table at
29 CFR 1910.134(d)(3)(i)(A). This includes note four of the APF table,
which requires the employer to have evidence to support an APF of 1000
for helmet/hood respirators. In addition, paragraph (d) of the standard
for general industry and maritime and paragraph (d)(2) of the standard
for construction require employers to assess the exposure of each
employee who is or may reasonably be expected to be exposed to
respirable crystalline silica at or above the action level, which will
provide employers with information to make appropriate respirator
selection decisions. OSHA concludes that these requirements, including
the referenced provisions in other OSHA standards, will adequately
protect employees from exposures to respirable crystalline silica
during abrasive blasting.
    Many commenters, including NIOSH, labor unions, public health
organizations, trade associations, occupational health medical
professionals, and public interest organizations, urged OSHA to ban the
use of silica sand as an abrasive blasting agent (Document ID 2167;
2173, p. 4; 2175, pp. 7-8; 2177, Attachment B, p. 37; 2178, Attachment
1, p. 3; 2212, p. 1; 2240, p. 2; 2244, p. 2; 2256, Attachment 2, pp.
12-13; 2282, Attachment 3, pp. 2, 18; 2341, p. 3; 2371, Attachment 1,
p. 31; 2373, p. 3; 3399, p. 6; 3403, p. 7; 3577, Tr. 779-780, 785, 790;
3586, Tr. 3319-3320, 3163; 3588, Tr. 3752; 4204, p. 81; 4223, pp. 104-
106). Some noted that 4 countries (Great Britain, Germany, Sweden, and
Belgium), several U.S. military departments, and 23 state Departments
of Transportation have already banned the practice (Document ID 2167;
2175, pp. 7-8; 2178, Attachment 1, p. 3; 2256, Attachment 2, pp. 12-13;
2212, p. 1; 2282, Attachment 3, p. 18; 2371, Attachment 1, p. 31; 2373,
p. 3; 3399, p. 6; 4204, p. 76).
    Fann Contracting, Dr. Kenneth Rosenman, an expert in occupational
and environmental disease, and Novetas Solutions noted the broad trend
of abrasive blasting operations moving away from sand (Document ID
2116, Attachment 1, pp. 31-32; 3577, Tr. 858; 3588, Tr. 3992-3993). The
American Federation of State, County and Municipal Employees reported
that several local Maryland unions no longer use silica-based blasting
agents and have substituted other materials, such as aluminum shot
(Document ID 2106, p. 2). Sarah Coyne, a former painter and current
Health and Safety Director for IUPAT, discussed how their signatory
contractors have largely transitioned from silica sand to coal slag for
abrasive blasting (Document ID 3581, Tr. 1644). API noted that many oil
and gas companies have limited or eliminated respirable crystalline
silica exposure in sandblasting operations by using media options that
do not contain silica (Document ID 2301, Attachment 1, p. 5). NADA also
noted that product substitution has minimized potential exposures to
airborne crystalline silica-containing media (Document ID 2358, p. 4).
The Interstate Natural Gas Association of America stated that members
utilize other abrasives to the extent feasible, including fused glass
in limited applications (Document ID 2081, p. 2).
    As OSHA indicated in its NPRM, the use of silica sand for abrasive
blasting operations is decreasing (Document ID 1420). This reduction
might reflect the use of alternative blasting media, the increased use
of high-pressure water-jetting techniques, and the use of cleaning
techniques that do not require open sand blasting. Several substitutes
for silica sand are available for abrasive blasting operations, and
current data indicate that the abrasive products with the highest U.S.
consumptions are: Coal slag, copper slag, nickel slag, garnet,
staurolite, olivine, steel grit, and crushed glass. Several commenters
(Adam Webster, Charles Gordon, and the Association of Occupational and
Environmental Clinics) also noted the general availability of
alternative abrasive blast media, including baking soda, water, dry
ice, coal/copper slag, glass beads, walnut shells, and carbon dioxide
(Document ID 2163, p. 19; 2167; 3399, p. 6). Additional alternatives
are discussed and evaluated in Chapter IV of the FEA. On the other
hand, PCI commented that the use of alternative abrasive blast media
was precluded in the precast concrete structures industry, since many
alternatives will not meet aesthetic requirements, are not aggressive
enough to provide the desired finished, or are simply cost prohibitive
(Document ID 2276, p. 9). Furthermore, CISC warned about possible
hazards associated with the substitutes for silica sand (Document ID
2319, p. 37). PCI and Novetas Solutions cautioned that coal and copper
slags, commonly used as a substitute for silica sand in abrasive
blasting, contain hazardous substances such as beryllium that cause
adverse health effects in employees (Document ID 2276, p. 9; 3588, Tr.
3992-4004). Meeker et al. (2006) found elevated levels of exposure to
arsenic, beryllium, and other toxic metals among painters using three

alternative blasting abrasives (Document ID 3855).
    A NIOSH study compared the short-term pulmonary toxicity of several
abrasive blasting agents (Document ID 1422). This study reported that
specular hematite and steel grit presented less short-term in vivo
toxicity and respirable dust exposure in comparison to blast sand.
Overall, crushed glass, nickel glass, staurolite, garnet, and copper
slag were similar to blast sand in both categories. Coal slag and
olivine showed more short-term in vivo toxicity than blast sand and
were reported as similar to blast sand regarding respirable dust
exposure. This study did not examine long-term hazards or non-pulmonary
effects.
    Additionally, another NIOSH study monitored exposures to several
OSHA-regulated toxic substances that were created by the use of silica
sand and substitute abrasive blasting materials (Document ID 0772). The
study showed that several substitutes create exposures or potential
exposures to various OSHA-regulated substances, including: (1) Arsenic,
when using steel grit, nickel slag, copper slag and coal slag; (2)
beryllium, when using garnet, copper slag, and coal slag; (3) cadmium,
when using nickel slag and copper slag; (4) chromium, when using steel
grit, nickel slag, and copper slag; and (5) lead, when using copper
slag. Since these studies were performed, OSHA has learned that
specular hematite is not being manufactured in the United States due to
patent-owner specification. In addition, the elevated cost of steel has
a substantial impact on the availability to some employers of
substitutes like steel grit and steel shot.
    Evidence in the rulemaking record indicates that elevated silica
exposures have been found during the use of low-silica abrasives as
well, even when blasting on non-silica substrates. For example, the use
of the blasting media Starblast XL (staurolite), which contains less
than one percent quartz according to its manufacturer, resulted in a
respirable quartz level of 1,580 [mu]g/m\3\. The area sample (369-
minute) was taken inside a containment structure erected around two
steel tanks. The elevated exposure occurred because the high levels of
abrasive generated during blasting in containment overwhelmed the
ventilation system (Document ID 0212). This example emphasizes the
impact of control methods in specific working environments. In order to
reduce elevated exposures to or as close as feasible to the PEL in
situations like these, employers need to examine the full spectrum of
available controls and how these controls perform in specific working
conditions.
    After considering the arguments for and against prohibition, OSHA
concludes that prohibiting the use of silica sand as an abrasive
blasting agent is not appropriate. In so concluding, the Agency
considered whether such a prohibition is an effective risk mitigation
measure, as well as the technological feasibility of substitutes. The
Agency finds that many of the silica sand substitutes used in abrasive
blasting can create hazardous levels of toxic dust other than silica,
as documented in studies conducted by NIOSH on the toxicity of silica
sand substitutes for abrasive blasting; NIOSH found that many,
including coal slag, garnet, copper and nickel slags, olivine, and
crushed glass, produced lung damage and inflammatory reactions in
rodent lung similar to that of silica sand, indicating that use of such
materials would present lung disease risks to employees (Document ID
3857; 3859). OSHA further finds that additional toxicity data are
necessary before the Agency can reach any conclusions about the hazards
of these substitutes relative to the hazards of silica. Given the
concerns about potential harmful exposures to other substances that the
alternatives might introduce in a workplace, as well as the potential
for continued exposure to respirable crystalline silica, OSHA concludes
that banning the use of silica sand as an abrasive blasting agent would
not necessarily effectively mitigate risk. OSHA also concludes, as
detailed in the FEA, that the general prohibition of silica sand in
abrasive blasting is not technologically or economically feasible.
Thus, the Agency has decided against a ban or limitation on the use of
silica sand as an abrasive blasting agent in the rule.
    BCTD urged OSHA to ban the use of silica sand as an abrasive
blasting agent, but said that if banning the use of silica sand as an
abrasive blasting agent was not possible, OSHA should prohibit the use
of dry silica sand as an abrasive blasting agent (Document ID 2371,
Attachment 1, p. 31). However, PCI noted that wet blasting with silica
sand cannot be used to finish concrete surfaces (Document ID 2276, p.
9). CISC noted the problems associated with excessive water application
on some worksites and argued that different environments and conditions
had not been analyzed to determine the effectiveness of wet methods for
abrasive blasting (Document ID 2319, p. 36).
    OSHA finds that a separate requirement for the use of wet blasting
methods when silica sand is used as a blasting agent is neither
necessary nor appropriate. Under paragraph (f)(1) of the standard for
general industry and maritime (paragraph (d)(3)(i) of the standard for
construction), employers are required to use engineering and work
practice controls, which include wet methods, to reduce and maintain
employee exposure to respirable crystalline silica at or below the PEL,
unless the employer can demonstrate that such controls are not
feasible. Therefore, where employee exposures exceed the PEL from
abrasive blasting with silica sand, employers must implement wet
blasting methods whenever such methods are feasible and would reduce
exposures, even if implementing this control does not reduce exposures
to or below the PEL. By not specifically mandating the use of wet
methods whenever sand is used as a blasting agent, the rule gives
employers who cannot feasibly use wet methods flexibility to determine
what controls to implement in order with comply with the PEL.
    Charles Gordon argued for a partial ban on the use of silica sand
as an abrasive blasting agent:

    Abrasive blasting with crystalline silica should be banned in
confined spaces and in the maritime industry. That is where acute
silicosis was most common and where it is hardest to protect
adjacent workers.
    In all other areas and operations, the employer must consult
MSDS's for substitutes for crystalline silica. If it is reasonable
to conclude that a substitute for crystalline silica is a safer
blasting media and will lead to a reasonable surface, then the
employer must adopt the substitute. If the employer concludes that
there is no safer reasonable substitute for crystalline silica, then
the employer must keep a brief written record of that determination
(Document ID 2163, Attachment 1, pp. 18-19).

While OSHA has declined to ban abrasive blasting with crystalline
silica in any setting, the Agency considers that the process of
selecting, evaluating, and adopting safer blasting agent substitutes
where feasible, is consistent with the analysis required under
paragraph (f)(1) of the standard for general industry and maritime
(paragraph (d)(3)(i) of the standard for construction). As part of
complying with this paragraph, employers must consider whether
substitutes for crystalline silica abrasive blasting agents are
available. Safer, effective, and feasible substitutes, where available,
should be included as part of the package of feasible engineering and
work practice controls required to reduce employee exposure to
respirable crystalline silica to or below the PEL. The Agency expects
that the requirements in the rule will incentivize

employer evaluation and adoption of substitute materials where
substitution is appropriate for the task and shown to be safe, while
avoiding substitutions that pose comparable or greater risk and
maintaining flexibility for employers to determine what controls to
implement in order to comply with the PEL.
    CISC questioned the application of the hierarchy of controls to
abrasive blasting, given the Agency's acknowledgement that respiratory
protection will still be necessary in many situations even after
implementing engineering and work practice controls (Document ID 2319,
p. 37). As discussed above, the Agency maintains its position that
adherence to the hierarchy of controls, which includes, where
appropriate and feasible, substitutes for silica sand, wet blasting,
LEV, proper work practices and housekeeping practices that reduce dust
emissions, is essential to help reduce the extremely high exposures to
respirable crystalline silica experienced by abrasive blasting workers
and workers who may be near them. The FEA describes how extremely high
exposures associated with dry abrasive blasting were significantly
reduced where controls, such as wet blasting and non-silica containing
abrasive blast media, were used (see Chapter IV of the FEA for further
discussion). By using engineering controls to reduce these exposures,
employees will be able to wear less restrictive respirators and will be
better protected if their respiratory protection fails. Engineering
controls also help protect others on the worksite from exposure to
respirable crystalline silica. Therefore, requiring the use of
controls, even where respiratory protection will also be required, is
reasonably necessary and appropriate to protect employees from
exposures to respirable crystalline silica.
    The requirements in the rule for abrasive blasting are consistent
with ASTM E 1132--06 and ASTM E 2625--09, the national consensus
standards for controlling occupational exposure to respirable
crystalline silica in general industry and in construction,
respectively. Each of these standards clarifies that the hierarchy of
controls (i.e., using alternative materials, wet suppression systems,
or exhaust ventilation, where feasible, to reduce exposures) applies to
abrasive blasting and refers to the existing requirements under OSHA's
ventilation standards (29 CFR 1910.94 and 29 CFR 1926.57).
    Employee rotation. OSHA proposed, but is not including in the final
rule, a provision specifying that the employer must not rotate
employees to different jobs to achieve compliance with the PEL. The
Agency proposed this prohibition because silica is a carcinogen, and
OSHA considers that any level of exposure to a carcinogen places an
employee at risk. With employee rotation, the population of exposed
employees increases. A prohibition on rotation has been included in
other OSHA health standards that address carcinogens, such as the
standards for asbestos (29 CFR 1910.1001), chromium (VI) (29 CR
1910.1026), 1,3-butadiene (29 CFR 1910.1051), methylene chloride (29
CFR 1910.1052), cadmium (29 CFR 1910.1027), and methylenedianiline (29
CFR 1910.1050). However, other standards addressing chemicals that were
associated with non-cancer health effects, such as the standards for
lead and cotton dust (29 CFR 1910.1025 and 29 CFR 1910.1043), do not
include a prohibition on employee rotation to achieve the PEL. In
response to a recommendation by the Small Business Advocacy Review
Panel, OSHA solicited comment in the NPRM on the prohibition of
employee rotation to achieve compliance with the PEL (78 FR 56273,
56290 (9/12/13)).
    A prohibition on employee rotation to achieve compliance with the
PEL was supported by EEI, Dr. George Gruetzmacher, and James Schultz
(Document ID 2278, p. 4; 2357, p. 30; 3586, Tr. 3200). However, many
commenters representing employers from the concrete, brick, tile,
construction, electric utility, and foundry industries, over 20 trade
associations, ASSE, and academics from the George Washington University
Regulatory Studies Center urged OSHA to reconsider this prohibition
(e.g., Document ID 1785, p. 8; 1831, p. 15; 1992, p. 11; 2023, p. 7;
2024, p. 3; 2075, p. 3; 2102, p. 2; 2116, Attachment 1, pp. 34-35;
2119, Attachment 3, p. 7; 2145, pp. 5-6; 2147, p. 4; 2150, p. 2; 2154,
Attachment 3, p. 7; 2185, pp. 6-7; 2195, p. 39; 2213, p. 4; 2215, p.
11; 2222, p. 2; 2241, p. 2; 2245, p. 3; 2255, p. 3; 2276, p. 10; 2279,
p. 10; 2288, p. 12; 2296, p. 42; 2305, pp. 11, 15; 2309, p. 3; 2322, p.
14; 2326, p. 3; 2339, p. 4; 2348, Attachment 1, p. 36; 2355, p. 2;
2359, Attachment 1, p. 11; 2370, p. 2; 2379, Appendix 1, p. 69; 2380,
Attachment 2, p. 21; 2384, p. 10; 2391, p. 2; 3245, p. 2; 3275, p. 2;
3489, p. 4; 3491, p. 4; 3578, Tr. 1035-1036, 1044; 3729, p. 3; 4194, p.
12; 4213, p. 7; 4226, p. 2).
    Some commenters misunderstood the prohibition on employee rotation
to achieve compliance with the PEL, or believed that the provision
could be misunderstood by the regulated community. These commenters
were concerned that the prohibition would preclude the use of rotation
for other reasons, such as limiting exposure to physical hazards (e.g.,
noise, vibration, repetitive motion stresses), providing cross-
training, improving productivity, preventing fatigue, and filling in
for other employees. OSHA explained in the NPRM that the proposed
provision was not intended as a general prohibition on employee
rotation. However, commenters including National Electrical Carbon
Products, OSCO, the Ohio Cast Metals Association, PCI, and AFS
expressed concerns that using employee rotation for these other reasons
could be misinterpreted as a violation of the prohibition (e.g.,
Document ID 1785, p. 8; 1992, p. 11; 2119, Attachment 3, p. 7; 2276, p.
10; 3489, p. 4;). NISA also asked the Agency to clarify that rotation
may be performed for purposes other than achieving compliance with the
PEL (Document ID 2195, p. 39).
    NISA and the Chamber argued that if the risks of silicosis are
subject to a threshold, then rotation to maintain exposures at low
levels could only be protective (Document ID 2195, p. 39; 2288, p. 12;
4194, p. 12). ASSE argued that job rotation may be warranted as an
alternative to burdensome engineering and administrative controls or
PPE for tasks that involve some levels of exposure to silica, but are
performed on an infrequent basis (Document ID 2339, p. 4; 3578, Tr.
1035-1036, 1044). ASSE, as well as Dal-Tile, noted that since silica is
a ubiquitous substance and present in many raw materials, virtually all
employees would be exposed to some level of respirable crystalline
silica. Therefore, they argued that a prohibition on rotation in this
circumstance does not make sense (Document ID 2147, p. 4; 2339, p. 4).
In addition, AFS indicated that rotation as an administrative control
is permitted by Canadian provinces with exposure limits for respirable
crystalline silica (Document ID 4035, p. 14). OSHA also notes that the
industry consensus standards for respirable crystalline silica, ASTM E
1132-06 and ASTM E 2625-09, expressly permit employee rotation as an
administrative control to limit exposures (Document ID 1466, p. 4;
1504, pp. 3, 7).
    OSHA does not consider employee rotation to be an acceptable
alternative to avoid the costs associated with implementation of
engineering and administrative controls, nor does the Agency consider
that pervasive exposures to respirable crystalline silica justify
allowing rotation. OSHA has nonetheless concluded that there may be
situations where employee rotation

may be an acceptable measure to limit the need for respiratory
protection. For example, OSHA has determined that the majority of
employers covered by the rule will be in construction, and expects that
most construction employers will implement the controls listed on Table
1 in paragraph (c) of the standard for construction. A number of tasks
listed on Table 1 require respiratory protection, in addition to
engineering and work practice controls, when performed for more than
four hours per shift. Where the employer has implemented the
engineering and work practice controls specified in Table 1, OSHA
accepts the rationale that it may be reasonable to rotate employees to
avoid exceeding the four-hour threshold that would trigger a
requirement for respirator use. As discussed earlier in this section,
respirator use can restrict visibility, impair communication,
contribute to heat stress, strain the respiratory and cardiac systems,
and exacerbate other safety and health hazards, such as trip and fall
hazards. Under such circumstances, rotation of employees to limit use
of respiratory protection may serve to reduce overall risks to
employees. Rotation may also allow employees to continue to work if
they are unable to pass the medical evaluation for respirator use, but
are otherwise capable of performing the work.
    OSHA also recognizes that a provision prohibiting employee rotation
to achieve the PEL has little practical application for purposes of
enforcement. Because the prohibition is limited to rotation for the
sole purpose of achieving the PEL, an employer can provide any other
reason to justify employee rotation. As described above, there are many
legitimate reasons for an employer to rotate employees. As a result,
OSHA has almost never cited employers for violating provisions
prohibiting employee rotation for achieving the PEL. For the 7
standards that contain these provisions, which have been in effect for
periods ranging from 8 to 29 years, Federal OSHA has only cited one of
these provisions on one occasion.
    For the reasons described above, OSHA has determined that a
prohibition on employee rotation to achieve the PEL is not reasonably
necessary or appropriate for the silica rule. The Agency recognizes
that this determination differs from the determinations made in
previous rulemakings addressing carcinogens. This is not intended as a
reversal of OSHA's prior practice of prohibiting employee rotation to
achieve the PEL for carcinogens, nor a precedent that will control
future rulemakings, which necessarily will be based on different
rulemaking records. Nevertheless, in this rule OSHA expects that the
majority of employers covered by the rule will implement all feasible
engineering and work practice controls to achieve the PEL (as the rule
requires), and rotation will generally be used to limit use of
respiratory protection that is triggered by working more than four
hours in conditions where exposures are expected above the PEL even
with the full implementation of engineering and work practice controls.
OSHA finds that these factors justify omitting the prohibition on
rotation from this rule. Therefore, the prohibition, which was included
in the proposed rule, is not included in the final rule.

Respiratory Protection

    Paragraph (g) of the standard for general industry and maritime
(paragraph (e) of the standard for construction) establishes
requirements for the use of respiratory protection, to which OSHA's
respiratory protection standard (29 CFR 1910.134) also applies.
Specifically, respirators are required under the rule: Where exposures
exceed the PEL during periods necessary to install or implement
engineering and work practice controls; where exposures exceed the PEL
during tasks, such as certain maintenance and repair tasks, for which
engineering and work practice controls are not feasible; and during
tasks for which all feasible engineering and work practice controls
have been implemented but are not sufficient to reduce exposure to or
below the PEL. The standard for general industry and maritime also
requires respiratory protection during periods when an employee is in a
regulated area. The standard for construction also requires respiratory
protection where specified by Table 1 of paragraph (c), but does not
include a requirement to establish a regulated area, and thus does not
contain a provision requiring the use of respirators in regulated
areas.
    These provisions of the rule for the required use of respirators
are consistent with those proposed and are generally consistent with
other OSHA health standards, such as methylene chloride (29 CFR
1910.1052) and chromium (VI) (29 CFR 1910.1026). They reflect the
Agency's determination that, as discussed in the summary and
explanation of Methods of Compliance, respirators are inherently less
reliable than engineering and work practice controls in reducing
employee exposure to respirable crystalline silica. OSHA therefore is
allowing reliance on respirators to protect against exposure to
respirable crystalline silica only in specific circumstances where
engineering and work practice controls are in the process of being
installed or implemented (and thus are not yet fully operational), are
not feasible, or cannot by themselves reduce exposures to the PEL. In
those circumstances, OSHA's hierarchy of controls contemplates
requiring the use of respirators as a necessary supplement to
engineering, work practice, and administrative controls.
    Paragraph (e)(1) of the standard for construction is revised from
the proposed standard in order to clarify where respiratory protection
is required. Paragraph (e)(1)(i) of the standard for construction
provides that, for employers following the specified exposure control
methods approach set forth in paragraph (c) of the standard for
construction, respiratory protection is required under the standard
where specified by Table 1. Table 1 in paragraph (c) of the standard
for construction specifies respirator use for certain listed tasks;
employers whose employees are engaged in those tasks have the option of
following Table 1 in order to comply with the standard. The specific
respiratory protection and minimum assigned protection factors (APF)
for the tasks listed on Table 1 are discussed in the summary and
explanation of Specified Exposure Control Methods. Paragraph (e)(1)(ii)
of the standard for construction establishes where respirators are
required for employees who are not performing tasks listed on Table 1
or where the engineering controls, work practices, and respiratory
protection described in Table 1 are not fully and properly implemented
(including where the employer chooses to follow paragraph (d) rather
than follow paragraph (c)). Specifically, respirators are required in
each of the situations described in paragraphs (e)(1)(ii)(A)-(C).
    Paragraph (g)(1)(i) of the standard for general industry and
maritime (paragraph (e)(1)(ii)(A) of the standard for construction)
requires the use of respirators in areas where exposures exceed the PEL
during periods when feasible engineering and work practice controls are
being installed or implemented. OSHA recognizes that respirators may be
needed to achieve the PEL under these circumstances. During these
times, employees will have to use respirators for temporary protection
until the hierarchy of controls has been implemented, at which point
respirators will not be needed, provided the PEL is no longer exceeded.
Employers must follow the

requirements for exposure assessment (see the summary and explanation
of Exposure Assessment) to determine the extent of employee exposures
once engineering and work practice controls are installed or
implemented. While there is not an established time for exposure
assessments to occur after the installation or implementation of
controls, employers are required to reassess exposures whenever a
change in control equipment may reasonably be expected to result in new
or additional exposures above the action level. Employers must also
ensure that employee exposures are accurately characterized, so they
would need to reassess exposures after the installation or
implementation of controls in order to meet this obligation.
    OSHA anticipates that engineering controls will be in place by the
dates specified in paragraphs (l)(2) and (l)(3) of the general industry
and maritime standard (paragraph (k)(2) of the standard for
construction) (see the summary and explanation of Dates for discussion
of these requirements). However, the Agency realizes that in some cases
employers may commence operations, install new or modified equipment,
or make other workplace changes that result in new or additional
exposures to respirable crystalline silica after the dates specified.
In these cases, a reasonable amount of time may be needed before
appropriate engineering controls can be installed and proper work
practices implemented. When employee exposures exceed the PEL in these
situations (see the summary and explanation of Exposure Assessment for
an explanation of the requirements to assess employee exposure to
respirable crystalline silica), employers must provide their employees
with respiratory protection and ensure its use.
    Paragraph (g)(1)(ii) of the general industry and maritime standard
(paragraph (e)(1)(ii)(B) of the standard for construction) requires
respiratory protection in areas where exposures exceed the PEL during
tasks in which engineering and work practice controls are not feasible.
OSHA anticipates that there will be few situations where no feasible
engineering or work practice controls are available to limit employee
exposure to respirable crystalline silica. However, the Agency
recognizes that it may be infeasible to control respirable crystalline
silica exposure with engineering and work practice controls during
certain tasks, such as maintenance and repair tasks, and permits the
use of respirators in these situations. For example, maintenance and
repair to address temporary failures in operating systems or control
systems to achieve the PEL such as failures of conveyance systems
(elevators, conveyors, or pipes), failures of dust collecting bag
systems, and section head failures at glass plant facilities as well as
cupola (furnace) repair work and baghouse maintenance activities, may
present a situation where engineering and work practice controls are
not feasible and the use of respirators is permitted (Document ID 3493,
p. 3; 1992, pp. 3, 5). In situations where respirators are used as the
only means of protection, the employer must be prepared to demonstrate
that engineering and work practice controls are not feasible.
    Paragraph (g)(1)(iii) of the standard for general industry and
maritime (paragraph (e)(1)(ii)(C) of the standard for construction)
requires the use of respirators for supplemental protection in
circumstances where feasible engineering and work practice controls
alone are not sufficient to reduce exposure levels to or below the PEL.
The employer is required to install and implement all feasible
engineering and work practice controls, even if these controls alone
cannot reduce employee exposures to or below the PEL. Whenever
respirators are used as supplemental protection, the burden is on the
employer to demonstrate that engineering and work practice controls
alone are insufficient to achieve the PEL.
    Paragraph (g)(1)(iv) of the standard for general industry and
maritime requires employers to provide respiratory protection during
periods when an employee is in a regulated area. Paragraph (e) of the
standard for general industry and maritime requires employers to
establish a regulated area wherever an unprotected employee's exposure
to airborne concentrations of respirable crystalline silica is, or can
reasonably be expected to be, in excess of the PEL. OSHA included the
provision requiring respirator use in regulated areas to make it clear
that each employee is required to wear a respirator when present in a
regulated area, regardless of the duration of time spent in the area.
Because of the potentially serious results of exposure, OSHA has
concluded that this provision is necessary and appropriate because it
would limit unnecessary exposures to employees who enter regulated
areas, even if they are only in a regulated area for a short period of
time. The standard for construction does not include a requirement to
establish a regulated area and thus, does not contain a similar
provision in the respiratory protection section of the standard.
Further discussion about this can be found in the summary and
explanation of Regulated Areas and Written Exposure Control Plan.
    OSHA proposed to require the use of respiratory protection when
specified by the written access control plan--an option given to
employers in the proposed rule as an alternative to establishing
regulated areas. The Agency is not including an access control plan
option in the rule (see discussion in the summary and explanation of
Regulated Areas). Thus, without an option for an employer to develop a
written access control plan, there is no reason to require respirators
pursuant to a written access control plan.
    Commenters, including Charles Gordon, a retired occupational safety
and health attorney, and the American Industrial Hygiene Association
recommended that OSHA require employers to provide employees with
respirators upon request in certain situations where they are not
required under the rule (e.g., exposures below the PEL, Table 1 tasks
for which respirators are not required) (Document ID 2163, Attachment
1, p. 16; 2169, p. 5). Dr. George Gruetzmacher, an industrial hygiene
engineer, suggested that OSHA require respiratory protection and a
respiratory protection program at the action level (Document ID 2278,
p. 4).
    While the Agency considers the level of risk remaining at the PEL
to be significant, OSHA is not including a provision in this rule
permitting employees to request and receive a respirator in situations
where they are not required under the rule, nor is OSHA requiring
respiratory protection and a respiratory protection program at the
action level. There has been significant residual risk below the PEL in
many previous health standards, but OSHA has only rarely included
provisions permitting employees to request and receive a respirator to
mitigate this risk (cotton dust (29 CFR 1910.1043(f)(1)(v)), lead (29
CFR 1910.1025(f)(1)(iii)), cadmium (29 CFR 1910.1027(g)(1)(v))) and the
Agency has never established a requirement for respiratory protection
and a respiratory protection program at a standard's action level.
    OSHA anticipates that most construction employers covered by the
rule will choose to implement the control measures specified in
paragraph (c) of the standard for construction. Employers who implement
the specified exposure control methods will not be required to assess
employee exposures to respirable crystalline silica. Therefore, many
employers covered by

the rule will not be aware if their employees are exposed to respirable
crystalline silica at or above the action level. In order to impose a
requirement for employers to provide respirators to employees exposed
at or above the action level, OSHA would first need to require
employers to assess the exposures of all employees in order to
determine which employees are exposed at or above the action level. As
discussed in the summary and explanation of Specified Exposure Control
Methods, OSHA has concluded that such an exposure assessment
requirement is not necessary for employers who implement the controls
listed on Table 1.
    With regard to permitting employees to request respirators for
Table 1 tasks where respiratory protection is not specified, OSHA has
relied on its technological feasibility analyses to determine which
tasks can be performed at or below the PEL most of the time with the
use of engineering and work practice controls only (i.e., without
respirators), and has concluded that employers who implement the
controls listed on Table 1 for these tasks will provide equivalent
overall protection for their employees as employers who perform
exposure assessment and follow the alternative exposure control methods
option provided in paragraph (d). If an employer follows Table 1 and
Table 1 does not require use of a respirator, the employee's exposure
will generally be below the PEL. There may be exceptions, but this is
no different than when monitoring is conducted--monitoring two or four
times a year does not perfectly characterize exposures, and there will
be situations where exposures exceed the PEL even when good faith
monitoring efforts by the employer indicate that exposures would be
below the PEL.
    If respirators were mandated at the action level or available upon
employee request in situations where they are not required under the
rule, employers would need to have respirators available at all times.
Moreover, they would need to establish and implement a full respiratory
protection program for all employees exposed to silica--a considerable
undertaking for many employers that involves not only the purchase and
retention of suitable respirators but an ongoing program of training,
fit-testing, and maintenance. OSHA concludes that ``on request''
respirator use or requiring respiratory protection at the action level
is not a practical or responsible approach to occupational safety and
health regulation, and requiring such an investment in respirators
would divert resources from the development and implementation of
engineering controls that could more effectively reduce exposure levels
to or below the PEL. Thus, OSHA's approach for reducing employee
exposure to respirable crystalline silica in this and all other
standards for air contaminants is to focus on engineering controls,
rather than additional requirements for respiratory protection. For
these reasons, OSHA has determined that a requirement for employers to
provide respirators to employees upon request in situations where they
are not required under the rule, or a requirement to provide
respirators to employees exposed at or above the action level, is not
reasonably necessary and appropriate for this respirable crystalline
silica rule.
    At the same time, OSHA does not prohibit employers from supplying
or employees from using respirators outside the requirements of the
rule. Therefore, although this rule does not include a provision
providing employees with a right to request and receive respirators
where not required by the rule, or requiring respiratory protection at
the action level, employers may continue to provide respirators at the
request of employees or permit employees to use their own respirators
in situations where respirator use is not required, as provided for in
the respiratory protection standard (29 CFR 1910.134(c)(2)(i)). OSHA's
understanding, however, is that such use beyond what is required in a
comprehensive OSHA standard is not a common occurrence, and the Agency
does not expect non-mandated respirator use to proliferate with respect
to this rule, as might well be the case if a provision requiring
employers to provide respirators ``on request'' was written into the
rule and would certainly be the case if the action level were used as
the trigger for respirator use.
    Industry commenters, including the Construction Industry Safety
Coalition, OSCO Industries, American Foundry Society, National
Association of Manufacturers, Glass Packaging Institute, American
Composite Manufacturers Association, Small Business Administration's
Office of Advocacy, U.S. Chamber of Commerce, and American
Subcontractors Association, urged OSHA to consider discarding the
hierarchy of controls and permitting the use of respirators in lieu of
engineering and work practices controls in various circumstances,
including: During short duration tasks performed intermittently
(Document ID 1992, pp. 3, 5; 2319, p. 115); where exposures exceed the
PEL for 30 days or less per year (Document ID 4229, p. 11); where
exposures are below the respirable dust PEL of 5 mg/m\3\ (Document ID
2380, Attachment 2, p. 24); for unanticipated maintenance issues
(Document ID 3493, pp. 2-3); for small businesses (Document ID 3588,
Tr. 3933-3936); for construction employers (Document ID 2187, p. 6;
2283, p. 3; 2349, p. 5); and for industries using large amounts of
crystalline silica (e.g., oil and gas operations where hydraulic
fracturing is conducted) (Document ID 2283, p. 3; 3578, Tr. 1091).
These comments are discussed in the summary and explanation of Methods
of Compliance. As indicated in that section, OSHA's longstanding
hierarchy of controls policy reflects the common assessment among
industrial hygienists and the public health community that respirators
are inherently less reliable than engineering and work practice
controls in reducing employee exposure to air contaminants like
respirable crystalline silica, and therefore, except in limited
circumstances, they should not be allowed as an alternative to
engineering and work practice controls, which are more reliable in
controlling exposures. Thus, the Agency has not included additional
situations where respirators are required in the respiratory protection
paragraph, but as previously discussed, recognizes that, in some
circumstances, such as certain maintenance and repair activities,
engineering and work practice controls may not be feasible and the use
of respiratory protection would be required.
    Paragraph (g)(2) of the general industry and maritime standard
(paragraph (e)(2) of the standard for construction) requires the
employer to implement a comprehensive respiratory protection program in
accordance with OSHA's respiratory protection standard (29 CFR
1910.134) whenever respirators are used to comply with the requirements
of the respirable crystalline silica standard. As contemplated in the
NPRM, a respiratory protection program that complies with the
respiratory protection standard will ensure that respirators are
properly used in the workplace and are effective in protecting
employees. In accordance with that standard, the program must include:
Procedures for selecting respirators for use in the workplace; medical
evaluation of employees required to use respirators; fit-testing
procedures for tight-fitting respirators; procedures for proper use of
respirators in routine and reasonably

foreseeable emergency situations; procedures and schedules for
respirator maintenance; procedures to ensure adequate quality,
quantity, and flow of breathing air for atmosphere-supplying
respirators; training of employees in respiratory hazards to which they
might be exposed and the proper use of respirators; and procedures for
evaluating the effectiveness of the program (78 FR 56274, 56467 (9/12/
13)).
    Many employers commented that they already have respiratory
protection programs in place to protect employees from exposures to
respirable crystalline silica (Document ID 1964; 2183, p. 1; 2276, p.
5; 2292, p. 2; 2301, Attachment 1, p. 5, 37; 2338, p. 2; 2366, p. 3;
3577, Tr. 711; 3583, Tr. 2386-2387). The International Union of
Bricklayers and Allied Craftworkers and the International Union of
Operating Engineers also indicated that their members' employers have
established respiratory protection programs (Document ID 2329, p. 7;
3583, Tr. 2342, 2367).
    The American Association of Occupational Health Nurses, Ameren
Corporation, 3M Company, and Dr. George Gruetzmacher supported the
reference to the respiratory protection standard (Document ID 2134;
2278, p. 3; 2313, p. 6; 2315, p. 4). For example, the 3M Company, which
manufactures respirators, stated:

    3M believes that by not requiring separate, individual
respiratory protection provisions for respirable crystalline silica,
the . . . rule should enhance consolidation and uniformity of the
1910.134 respirator requirements and could result in better
compliance concerning the use of respiratory protection. Many of our
customers use respirators to help protect workers from exposures to
multiple contaminants and the reference in the respirable
crystalline silica standard to the requirements of 1910.134 brings
uniformity that could likely result in better compliance and
protection for workers with exposures to silica and other materials
(Document ID 2313, p. 6).

Expressing an opposing view, the National Stone, Sand, and Gravel
Association commented that the respiratory protection paragraph was
duplicative of existing requirements in 29 CFR 1910.134 (Document ID
2327, Attachment 1, p. 11).
    OSHA concludes that referencing the requirements in the respiratory
protection standard is important for ensuring that respirators are
properly used in the workplace and are effective in protecting
employees. Simply cross-referencing these requirements merely brings
the applicable requirements to the attention of the employer; the
cross-reference does not add to the employer's existing legal
obligations, but it makes it more likely that the employer covered by
this standard will meet all its obligations with regard to providing
respirators when required to do so. Thus, the Agency has incorporated
in the rule the reference to the respiratory protection standard that
was proposed.