A Possible Sneak Peek Into MSHA’s Silica Proposal

By Nickole Winnett

Operators and Employers Should Review Historical Sampling Results, Validity Of Current Citations, And Control And Protection Programs.

The Occupational Safety and Health Administration’s (OSHA) Notice of Proposed Rulemaking (NPRM) for Occupational Exposure to Respirable Crystalline Silica was published on Sept. 12, 2013, in the Federal Register. The NPRM concerns the occupational hazards associated with inhaling very small (respirable) crystalline silica particles in construction, maritime and general industry.

If adopted, OSHA’s rule would reduce the permissible exposure limit (PEL) and implement ancillary provisions, such as exposure monitoring, respiratory protection, medical surveillance, hazard communication and recordkeeping.

Crystalline silica is the second most common mineral in the Earth’s crust, and is a major component of sand, rock and mineral ores.

Occupational exposure to respirable crystalline silica can occur in mining, hydraulic fracking, foundry work, abrasive blasting operations, paint manufacturing, glass and concrete product manufacturing, brick making, china and pottery manufacturing, and construction activities, such as cutting and drilling stone and rock, masonry work, and jack-hammering.

Inhalation of respirable crystalline silica has been linked to silicosis, a lung disease that results in fibrous or scar tissue formations in the lungs, which reduce the lung’s ability to work to extract oxygen from the air.

According to the Centers for Disease Control (CDC), the silicosis mortality rate in the U.S. declined by 93 percent from 1968-2007 – falling from 1,157 cases in 1968 to about 150 cases in 2007.

While even one silica-related death is too many, the CDC data indicates that silica disease mortality is vanishing under the current PEL, calculated as an 8-hour time-weighted average, of approximately 100 micrograms of respirable crystalline silica per cubic meter of air (100µg/m³) in general industry and mining and 250µg/m³ in construction.

When viewed in the context of OSHA-compliance data showing that 30 percent of OSHA silica samples exceed the current exposure limit, it makes a strong case that the current rule is protective, and if there is a remaining risk, it can be solved by enforcement of current OSHA rules.

Despite the data, however, OSHA’s proposed rule would reduce the PEL for both general industry and construction to 50µg/m³ with an Action Level of 25µg/m³ to trigger initial and periodic exposure monitoring. The National Institute for Occupational Safety and Health also recommends a 50µg/m³ PEL for respirable crystalline silica.

With such a significant reduction of the PEL, there are serious questions about whether the sampling and analytical methods used in calculating the PEL and Action Level are capable of producing accurate results.

For example, there is no confirmation of the dust size collected (respirable = less than 10 microns) and there are known interferences by other minerals in silica identification. Variation among laboratory calibrations, error rates and round robin tests also indicate that monitoring results may not be accurate.

Other elements of OSHA’s proposal include the following:
Exposure Monitoring and Assessment
Provide exposure monitoring of employees who are or may reasonably be expected to be exposed to respirable crystalline silica at or above the Action Level of 25µg/m³. The exposure monitoring must be completed every six months if the initial monitoring indicates that employee exposures are at or above the Action Level and every three months if the initial monitoring indicates that employee exposures are above the PEL.
Employee Notification
Notify each affected employee in writing of the results of the monitoring or post the results in an appropriate location accessible to all affected employees. Whenever exposure is above the PEL, employers must describe the corrective action being taken to reduce employee exposure to or below the PEL.
Regulated Areas or Access Control Plan
Establish and implement either a regulated area or an access control plan whenever an employee’s exposure to respirable crystalline silica is, or can reasonably be expected to be, in excess of the PEL.
Protective Work Clothing
Provide appropriate protective clothing such as coveralls or similar full-bodied clothing or any other means to remove excessive silica dust from contaminated clothing if there is a potential for employees’ work clothing to become grossly contaminated with crystalline silica.
Respiratory Protection
Provide respiratory protection:
(1) where exposures exceed the PEL during periods necessary to install or implement feasible engineering and work practice controls; (2) where exposures exceed the PEL during work operations for which engineering and work practice controls are not feasible; (3) during work operations for which an employer has implemented all feasible engineering and work practice controls and such controls are not sufficient to reduce exposures to or below the PEL; and (4) during periods when the employee is in a regulated area or when an access control requires use of a respirator.
Medical Surveillance
Provide medical surveillance at no cost to the employee for each employee who will be occupationally exposed to respirable crystalline silica above the PEL for 30 or more days per year. Medical surveillance includes an initial medical examination within 30 days after initial assignment, unless the employee has received a medical examination that meets the requirement within the last three years, and periodic medical examinations at least every three years or more frequently if recommended.
Hazard Communication
Communicate and train employees on the hazards associated with crystalline silica under the Hazard Communication Standard (HCS), 29 C.F.R. § 1910.1200, and ensure that each employee has access to labels on containers of crystalline silica and safety data sheets.
Maintain an accurate record of each employee’s medical surveillance and the exposure measurement results, including the objective data used or relied on to characterize employee exposure to respirable crystalline silica.

It is anticipated that MSHA will similarly propose reducing the PEL to 50µg/m³, with an Action Level of 25µg/m³.

Given the focus on silica from OSHA and MSHA, we suggest that operators and employers review historical sampling results, the validity of current citations, and their control and protection programs.

Employers should also consider and provide comments on the OSHA proposal to ensure that their concerns are heard and addressed by the agencies. 

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