In the new silica rule, OSHA allows employers who aren’t controlling exposures via Table 1 to instead make hazard assessments through a combination of personal sampling and objective data. The question we continue to hear from both contractors and safety and health practitioners is “What is objective data and where can I find it?”

During the silica rulemaking process, testimony from OSHA and other subject matter experts suggested the use of objective data as a way to relieve small contractors from the burden of constantly conducting personal sampling of slightly different yet continually changing construction environments.

In the past, objective data has loosely referred to a collection of sampling data conducted by employers, government agencies (e.g., OSHA, NIOSH, MSHA) and academic institutions. It is often data that is referenced in research studies, journals and by standard-setting organizations. This data is usually public and is generally accepted to signify potential exposure levels. As a result of this tacit consensus, it provides data points for a baseline assumption of potential exposures. Reported exposure data that lie outside of the range considered to be normal can then be called into question and investigated further.

Therefore, in a practical sense, we can reliably use objective data to determine that a new jackhammer emits 105-110 decibels (dB) and that a muffler reduces these noise levels by 5-10 dB. We can say this with some confidence because it’s based on a cross section of easily referenced objective data given the state of current technology. If a reported set of data stated that a jackhammer only emitted 90 dB, that would raise eyebrows and be subject to scrutiny. Likewise, a jackhammer found to be emitting 120 dB would be subject to replacement.

For an industrial hygienist, however, relying too heavily on objective data becomes problematic. Objective data may be useful for making generalized hazard assumptions, but industrial hygienists are always concerned about the variability of unique conditions that may lead to higher than expected personal exposures. This is a very important piece of the puzzle in construction, since worksites are ever-changing, unpredictable and transient by nature. These issues can be obscured in objective data because most of the time they only include generic workplace descriptions that do not go further than specifying broad environmental conditions such as whether the work was done indoors or outdoors.

In the final silica rule, it seems that OSHA sought to address these concerns by proposing a more narrow definition of objective data. OSHA defines it as “information, such as air monitoring data from industry-wide surveys or calculations based on the composition of a substance, demonstrating employee exposure to respirable crystalline silica associated with a particular product or material or a specific process, task or activity.” OSHA goes on to specify that “the data must reflect workplace conditions closely resembling or with a higher exposure potential than the processes, types of material, control methods, work practices and environmental conditions in the employer’s current operations.” That’s a very specific definition.

Unfortunately, objective data as it’s currently defined by OSHA doesn’t seem to exist. Most of the publicly referenced data that’s available is not nearly specific enough to meet OSHA’s definition. Without notation of work practices and conditions, substrate and environmental conditions, even an employer’s historical sampling data would not be sufficient.

So where does that leave us in terms of compliance with the new rule? For employers not following Table 1, it’s back to constantly sampling. Until an OSHA-supported repository is developed, employers not using Table 1 must collect personal sampling data – notated with the workplace conditions – and ensure the current workplace conditions closely resemble those prior conditions.

For help with lowering silica exposures on your site and complying with the new silica rule, contact the LHSFNA’s OSH Division at 202-628-5465. LIUNA District Councils, Local Unions and signatory contractors can also order silica materials from our online Publications Catalogue.

[Walter Jones is the LHSFNA’s Director of Occupational Safety and Health.]