Limiting exposure

Features - Operations Focus

The construction industry is taking a stance on OSHA’s proposed silica rule that could have implications for demolition and recycling practices.

April 29, 2014
Kristin Smith

The Occupational Safety and Health Administration’s (OSHA’s) mission is to assure safe and healthful working conditions for working men and women by setting and enforcing standards and by providing training, outreach, education and assistance. Since its creation by Congress in 1970, its rules have improved working conditions for many industries. Yet a recent proposed rule to lower worker exposure to crystalline silica is drawing opposition from multiple construction trades that say the rule goes too far.

“Exposure to airborne silica dust occurs in operations involving cutting, sawing, drilling and crushing of concrete, brick, block and other stone products and in operations using sand products, such as in glass manufacturing, foundries and sand blasting,” OSHA stated when it announcement its Notice of Proposed Rulemaking on Occupational Exposure to Crystalline Silica in late August 2013. According to the agency, exposure to crystalline silica dust can cause a plethora of health issues, including lung cancer, silicosis, chronic obstructive pulmonary disease (COPD) and kidney disease.

OSHA’s proposed rule would lower the permissible exposure limits (PEL) to 50 micrograms per cubic meter (µg/m3) for all covered industry sectors as an eight-hour time-weighted average (TWA) for all forms of respirable crystalline silica. Current levels for workplace exposure to silica were adopted in 1971 and are 100 µg/m3 for general industry and 250 µg/m3 as a TWA for the construction industry.

OSHA estimates that once the full effects of the new proposed rule are realized, it will save nearly 700 lives and prevent 1,600 new cases of silicosis per year.

While the PELs are the same for all industries, the proposal includes two separate standards, one for general industry and one for construction. “OSHA is also proposing ancillary provisions for employee protection such as methods for controlling exposure, respiratory protection, medical surveillance, hazard communication and recordkeeping,” said William Perry, acting director, Directorate of Standards and Guidance for OSHA during his opening statement at a March 18 public meeting on the rule. The meeting was the first of a series of public hearings that took place in March and April.

Perry continued, “For the construction proposal, OSHA developed a novel approach that would give employers an option, for certain operations, to implement dust controls and practices that are specified in a table included in the standard and not have to conduct periodic exposure monitoring.”

Prior to the public hearing, on Feb. 18, the Construction Industry Safety Coalition (CISC) requested OSHA withdraw its proposed rule. The CISC is made up of about two dozen trade associations. The coalition represents associations from all sectors of the construction and demolition industry, including commercial building, heavy industrial production, home building, road repair, specialty trade contractors and material suppliers. The group says workplace safety and health is a priority for all members of the coalition, and each is committed to helping create safer construction job sites for workers.

One CISC member, the National Demolition Association (NDA), Doylestown, Pa., has been vocal in its opposition of the proposal in its current form. “It is the current position of the Construction Industry Safety Coalition and the NDA that the OSHA proposed silica rule is impractical, does not take into consideration the everyday practices on construction and demolition sites across the country, has elements impossible to enforce and will have significant impact on the American construction economy,” writes NDA Executive Director Mark Taylor in a blog on NDA’s website,

Taylor says in a separate statement, “From the point of view of the demolition industry, OSHA’s proposed crystalline silica rule is unworkable. We do not feel that OSHA has demonstrated that the proposed PEL can be met by demolition industry stakeholders involved in most of the operations we undertake.”

According to Taylor, many in the CSIC believe OSHA has not adequately shown the proposal is technologically and economically feasible. He says CSIC estimates the costs to the demolition and construction industry to comply with the proposed rule would be $2.2 billion. “The NDA, along with its fellow member organizations, which make up the CSIC, welcome the chance to productively collaborate with OSHA on the standard to find the most common-sense way to continue the trend of reducing crystalline silica exposure on demolition and construction job sites,” Taylor says.

As mentioned by Perry, the silica proposal includes a table on “Exposure Control Methods for Selected Construction Operations.” The table gives “Engineering and Work Practice Control Methods” and “Required Air-Purifying Respirator” for 13 different operations. For example, under the “Rock Crushing” category, it says, “Use wet methods or dust suppressants or use local exhaust ventilation systems at feed hoppers and along conveyor belts.” Another category, “Use of Heavy Earthmoving Equipment,” says to “operate equipment from within an enclosed cab having the following characteristics:

  • cab is air conditioned and positive pressure is maintained;
  • incoming air is filtered through a prefilter and HEPA (high-efficiency particulate air) filter;
  • cab is maintained as free as practicable from settled dust; and
  • door seals and closing mechanisms are working properly.”

The CSIC filed written prehearing comments on OSHA’s proposed rule on occupational exposure to crystalline silica in which it recommended OSHA implement the table without changing the PELs. “One of the things that we said in our 135 pages is you can avoid a lot of problems if you just implement the table,” explains Taylor.

Taylor says the CSIC wants to convey to OSHA that it shares the same concerns about exposure of silica dust to its workers. “We are trying to protect our most valuable asset,” he says. “That is our skilled, trained work force. If this is a major problem, and there are ways to do this without bankrupting our members and also that is technologically feasible, tell us what you think it is and we will certainly look at all those options.”

Equipment manufacturers have taken measures in their designs to eliminate dust as well, says Taylor. For example, most attachments that cut through concrete have the capability to spray water from the boom arm. Mobile crushing plants are designed to create minimal dust, he adds.

Public hearings on the proposed silica rule concluded April 4. According to OSHA, at the close of the hearing, those participants who have filed notices of intent to appear will have the opportunity to file additional evidence and data relevant to the proceeding and to file final written briefs.

Additional information and data relevant to the proceeding must be submitted within 45 days of the close of the hearing; final briefs, arguments and summations must be submitted 90 days after the close of the hearing.

“We look forward to receiving feedback from our stakeholders on our proposal, and we’re grateful for the continuing high level of public engagement throughout the rulemaking,” Assistant Secretary of Labor for Occupational Safety and Health Dr. David Michaels said at the beginning of the hearings. “This is an open process and the input we receive will help us ensure that a final rule adequately protects workers, is feasible for employers and is based on the best available evidence.”

The author is managing editor of Construction & Demolition Recycling and can be reached at

Making a proposal

A link to OSHA’s Notice of Proposed Rulemaking on Occupational Exposure to Crystalline Silica is available in its entirety online at