Silica Comes Back Into Focus

Silica exposures are once again in focus due to the Occupational Safety and Health Administration’s (OSHA) recent implementation of new silica standards for the construction, general, and maritime industries. These new regulations raise questions about enforcement, compliance requirements, and strategies for employers looking to manage their potential risks.

Silica is a compound consisting of the elements silicon and oxygen (silicon dioxide). It occurs as both crystalline and amorphous minerals, and both the crystalline and amorphous types are common substances used in construction and manufacturing for centuries.

Crystalline silica that becomes airborne as dust with a particle size of 10 microns and smaller is considered respirable. As a reference, particles visible to the naked eye are typically 100 microns in diameter and larger. Only very small particles of silica—less than five microns—are more likely to be deposited in the lungs of humans. Silica’s crystalline forms (quartz, cristobalite, and tridymite) have hazardous properties that can cause serious health effects under certain circumstances.

OSHA estimates that over 2.3 million American workers are at risk for exposure to crystalline silica. Health effects are predominantly associated with long-term, work-related cumulative exposures, but adverse health effects may occur from very high, acute, short-term exposures. Diseases connected with inhalation of respirable silica include:

• Silicosis.

• Lung Cancer.

• Chronic Obstructive Pulmonary Disease (COPD).

• Kidney Disease.

Some of the industries most affected by exposures to respirable crystalline silica include abrasive blasting; cement and concrete working; foundries; hydraulic fracturing in oil and gas; mining; and stone surfacing and countertop manufacturing.

Regulatory Enforcement

The new OSHA silica standards set a permissible exposure limit (PEL) at 50 µg/m3 average over an eight-hour day and establish an action level of 25 µg/m3. OSHA claims its new rule will curb lung cancer, silicosis, chronic obstructive pulmonary disease, and kidney disease, and projects that the lower PEL will save more than 600 lives per year. It also predicts that the new rule will prevent more than 900 new cases of silicosis annually. In projecting the economic impact of the new rule, OSHA estimates the rule will provide average annual net benefits over the next 60 years of $3.8 to $7.7 billion. The rule is also expected to result in annual costs of about $1,524 for the average workplace covered by the rule.

OSHA’s enforcement of the rule for the construction industry (29 C.F.R. 1926.1153) has gradually increased since compliance requirements took effect on Sept. 23, 2017. During the first six months after the rule became effective, the federal and state-run agencies tasked with enforcing it cited 116 violations nationwide—and this figure will likely increase because OSHA can take up to six months after an inspection to issue citations.

Of the 116 silica violations currently cited, the most frequent citation (35 cases) involved employers failing to measure silica exposure levels. In addition, 31 violations were issued for failure to follow procedures intended to reduce silica exposure. Eighty percent of the cases were classified as serious violations. While OSHA can propose serious-violation fines as high as $12,934, the costliest proposed penalty was $9,239. An informal settlement knocked the fine down to $6,929.

OSHA’s enforcement of the rule for general industry (29 C.F.R. 1910.1053) began on June 23, 2018. On June 25, OSHA issued interim enforcement guidance in a memorandum titled, “Interim Enforcement Guidance for the Respirable Crystalline Silica in General Industry/Maritime standard,” 29 CFR 1910.1053. The memo states that OSHA intends to issue interim enforcement guidance until a compliance directive on the new standards is finalized.

Managing the Risks

How can employers manage their risks and comply with OSHA’s standard? A good first step is to determine if there are any potential crystalline silica exposure sources in their operations. This typically involves measuring airborne concentrations in the breathing zones of workers and having the samples analyzed by an accredited laboratory that specializes in industrial hygiene chemistry.

Once exposures are evaluated and documented, employers should establish and implement a written exposure-control plan that identifies tasks that involve silica exposures and methods used to protect workers.

Employers should consider the general industrial hygiene hierarchy of controls for exposure of contaminates, ranked from most effective to least effective:

1. Elimination.

2. Substitution.

3. Engineering Controls.

4. Administrative Controls.

5. Personal Protective Equipment.

Employers’ first consideration should be to eliminate the crystalline silica material and substitute a less toxic substance. As the elimination or substitution of silica-containing materials are often not feasible, employers that use crystalline silica or products containing crystalline silica are required to comply with the new OSHA silica regulations and rely on engineering controls, administrative controls, and personal protective equipment (respirators) to control risks of exposures to employees.

In the General Industry and Maritime Standards, exposures above OSHA’s PEL or action limit (AL) require controls that will reduce exposures below the PEL or AL. These may include engineering controls such as local exhaust ventilation, or, if engineering controls are not feasible, respirators.

Engineering controls to limit exposure to the new PEL are required by June 23, 2021 for any hydraulic fracturing operations in the oil and gas industry.

Because controls for respirable crystalline silica in hydraulic fracturing are still in development, the rule allows hydraulic fracturing employers additional time to implement engineering controls to take advantage of emerging technologies. Those employers do not have to implement engineering controls to limit exposures to the new PEL until June 23, 2021, three years later than other general industry and maritime employers. From June 23, 2018 to June 23, 2021, hydraulic fracturing employers can continue to have employees use respirators when exposures exceed the PEL.

When employers use respirators to control exposures, it is important to know these devices are covered by additional OSHA regulations requiring a written respiratory protection program, employee training, annual medical clearances, and respirator fit testing.

Additionally, employers should consider limiting workers’ access to areas where they may be exposed above the PEL and implement housekeeping practices that minimize dust generation.

Employers must offer medical exams—including chest X-rays and lung function tests—every three years for workers exposed at or above the AL for 30 or more days per year. Medical surveillance must be offered to employees who will be exposed above the PEL for 30 or more days a year starting June 23, 2020.

Important compliance actions include:

• Providing worker training on how to minimize silica exposures.

• Repeating training periodically and at the time of hire for new employees.

• Supervisor participation in training employees and enforcing compliance.

• Keeping records of air sampling, workers’ silica exposure levels, and medical exams.

• Conducting a periodic review/audit of these records by trained personnel to ensure OSHA criteria are being met.

Looking Forward

The new silica regulations raise a number of challenges about enforcement, compliance requirements, and strategies for employers looking to manage their potential risks. Employers must be diligent in identifying their silica hazards and, depending on their industry, implementing appropriate controls. Employers that turn a blind eye to their hazards will likely be cited upon inspection.

Through its authority, OSHA will continue to provide guidance documents, FAQs, videos, and other online materials to aid employers in managing silica risks and complying with the new standard.