OSHA's respirable crystalline silica standards require an employer to offer a medical exam to any worker whose silica exposure crosses a set threshold on 30 or more days a year. The threshold is different in construction and in general industry. The exam must be offered at no cost to the employee, at a reasonable time and place.

This requirement is called medical surveillance. The rule is in paragraph (h) of 29 CFR 1926.1153 for construction and paragraph (i) of 29 CFR 1910.1053 for general industry and maritime. It decides which employees must be offered exams, when the exams are due, and what health information the employer may receive.

Last updated: September 25, 2026.

Who triggers the exam requirement

Construction (1926.1153) General industry and maritime (1910.1053)
Trigger Employee will be required to use a respirator under the standard Employee will be exposed at or above the action level of 25 µg/m³ (8-hour TWA)
Duration 30 or more days a year 30 or more days a year
Cost to employee None None

In construction, the trigger is respirator use, not a measured exposure level. OSHA confirmed this in a 2018 letter of interpretation on the construction standard.

In general industry, the trigger is exposure at or above the action level. The action level is 25 µg/m³. It is half the permissible exposure limit (PEL) of 50 µg/m³. Under the general industry standard, this obligation took effect in two stages:

  • June 23, 2018: employees exposed above the PEL for 30 or more days a year.
  • June 23, 2020: employees exposed at or above the action level for 30 or more days a year.

The employer is responsible for tracking which employees reach 30 days. The employer must offer the exam without waiting for the employee to ask.

The exam, its timing and the reports

Timing

  • Initial (baseline) exam: offered within 30 days of initial assignment. If the employee had a qualifying exam within the previous three years, a new baseline exam is not required.
  • Periodic exam: offered at least every three years. It must be offered more often if the examining clinician recommends it.

Who performs it

All exams and procedures must be performed by a physician or other licensed health care professional (PLHCP). A PLHCP is anyone whose license, registration or certification legally permits them to provide, or be delegated, the required health services.

What the exam includes

  • Medical and work history.
  • Physical exam with emphasis on the respiratory system.
  • Chest X-ray. It must be interpreted and classified under the ILO International Classification of Radiographs of Pneumoconioses by a NIOSH-certified B Reader.
  • Pulmonary function test.
  • Test for latent tuberculosis infection. This is required at the initial exam only.
  • Any other test the PLHCP considers appropriate.

What each party receives

  • The employee receives a written medical report within 30 days of the exam. It covers the results, any limits on respirator use, any limits on silica exposure, and any recommended specialist referral.
  • The employer obtains a separate written opinion within 30 days of the exam. It is limited to the exam date, a statement that the exam met the standard, and any limits on respirator use. It contains more only if the employee authorizes it in writing.

Diagnoses and other findings stay between the employee and the PLHCP unless the employee authorizes disclosure.

Specialist referral

OSHA's Appendix B guidance identifies a chest X-ray classification of 1/0 or higher on the ILO scale as a criterion for referral to a specialist. Appendix B is non-mandatory.

Watsontown, 2026

OSHA inspected General Shale Brick Inc., doing business as Watsontown Brick Company, in Watsontown, Pennsylvania, in February 2026. The case was announced on August 26, 2026. Proposed penalties totaled $496,528.

The citations included:

  • 3 willful violations.
  • 4 serious violations.
  • 1 repeat violation.
  • 1 other-than-serious violation.

Among the cited failures, the company did not provide medical exams to employees exposed at actionable silica levels for 30 or more days a year. This is the general industry trigger in 1910.1053(i). The medical surveillance failure was cited together with failures in exposure assessment, respiratory protection and regulated areas.

What it is not

Silica medical surveillance Respirator medical evaluation
Purpose Early detection of silica-related disease Clearance to wear a respirator
When Within 30 days of assignment, then at least every 3 years Before the employee uses a respirator
Includes chest X-ray and lung function test Yes Not required by the silica standard

The two are separate obligations. Where respiratory protection is required, the employee must complete a medical evaluation before using a respirator. That evaluation does not replace the silica exam.

The action level is also not the exposure limit. Exposure at 25 µg/m³ is legal. In general industry, it still triggers the exam requirement once it occurs on 30 or more days a year.

Checks for the employer

  • List every employee who reaches the trigger on 30 or more days a year

    In construction, count days of required respirator use. In general industry, count days at or above 25 µg/m³.

  • Confirm the baseline exam was offered within 30 days of assignment

    Or record the date of a qualifying exam within the previous three years.

  • Confirm the clinic uses a NIOSH-certified B Reader for chest X-rays

    The standard requires B Reader classification under the ILO system.

  • Record refusals

    Under the construction standard, offering the exam meets the obligation even if the employee declines. OSHA recommends a signed refusal statement.

  • Request only the limited written opinion

    The employer is entitled to the exam date, the compliance statement and respirator limits. Anything more requires the employee's authorization.

  • Keep exam records

    Medical exam results are among the records the standard requires employers to keep.

Medical surveillance is one part of a silica program. The written exposure control plan sets out the tasks and controls that determine who reaches the trigger. The other obligations are covered in the 2026 silica standards.