29 CFR 1910.1052: OSHA Methylene Chloride Standard

Regulatory citation: 29 CFR 1910.1052, Methylene Chloride

What Is the OSHA Methylene Chloride Standard?

Section 1910.1052 applies to all occupational exposure to methylene chloride (MC) in general industry, construction and shipyard work. MC is a solvent used in paint stripping, degreasing, adhesives, pharmaceuticals and chemical processing.

Why Methylene Chloride Matters

MC is a volatile solvent, so vapor levels can rise quickly in enclosed or poorly ventilated spaces. The standard requires hazard information to address cancer, cardiac effects, central nervous system effects, liver effects, and skin and eye irritation.

Core Obligations

1. Keep Exposure Below the Limits (1910.1052(b) and (c))

The permissible exposure limit (PEL) is 25 parts per million (ppm) as an 8-hour time-weighted average (TWA). The short-term exposure limit (STEL) is 125 ppm over 15 minutes. The action level is 12.5 ppm as an 8-hour TWA.

2. Monitor Exposure (1910.1052(d))

Initial monitoring determines each employee's 8-hour TWA and 15-minute exposures. Table 1 then sets the frequency. Where exposure is above the TWA PEL, 8-hour monitoring is repeated every 3 months. Where it is at or above the action level but at or below the TWA PEL, it is repeated every 6 months. Where exposure is above the STEL, 15-minute monitoring is repeated every 3 months. Employees must be told their results within 15 working days after the employer receives them.

3. Set Up Regulated Areas (1910.1052(e))

A regulated area is required wherever exposure exceeds, or can reasonably be expected to exceed, the TWA PEL or the STEL. Access is limited to authorized people.

4. Use Engineering and Work Practice Controls (1910.1052(f))

Engineering and work practice controls must reduce exposure to or below the PELs, with respirators added where they are not enough. Employee rotation may not be used to comply.

5. Use the Right Respirators (1910.1052(g))

Respirators must be used under a program that meets 29 CFR 1910.134. Because MC can irritate or damage the eyes, employers must not select or use half mask respirators of any type. Escape respirators must be either a self-contained breathing apparatus or a gas mask with an organic vapor canister.

6. Prevent Skin and Eye Contact (1910.1052(h) and (i))

Protective clothing and eye and face protection must be provided at no cost where needed. Where skin or eye contact with solutions containing 0.1% or more MC is reasonably foreseeable, washing facilities and eyewash facilities are required.

7. Provide Medical Surveillance (1910.1052(j))

Medical surveillance covers employees exposed at or above the action level on 30 or more days a year, or above the TWA PEL or STEL on 10 or more days a year. Periodic surveillance is due within 12 months of the last one for employees aged 45 or older, and within 36 months for younger employees. The written medical opinion is due within 15 days after the evaluation of medical and laboratory findings is complete. A removed employee keeps earnings, seniority and other rights for up to 6 months.

8. Communicate Hazards, Train and Keep Records (1910.1052(k) to (m))

MC must be included in the hazard communication program. Training is required before or at initial assignment to a job with potential MC exposure. Exposure records must be kept for at least 30 years, and medical records for the duration of employment plus 30 years.

Common Compliance Approaches

Substitute Where Possible

Many paint stripping and degreasing jobs can switch to other products. Substitution removes the need for most of the standard.

Ventilate and Measure Short-Term Peaks

Tank work and small rooms can push exposure over the STEL quickly. Use local exhaust and take 15-minute samples during the worst tasks.

Example: Methylene Chloride Controls in Practice

A plastics fabricator uses an MC-based solvent to weld acrylic parts in a booth. Sampling shows operators at 40 ppm as an 8-hour TWA, above the PEL. The shop sets up a regulated area, adds exhaust ventilation and issues full facepiece supplied-air respirators while it tests a non-MC adhesive. It resamples within 3 months. Two operators, one aged 52 and one aged 30, enter medical surveillance on 12-month and 36-month cycles.

Related regulations: OSHA respiratory protection, OSHA Hazard Communication, OSHA access to exposure and medical records.

Note: EPA's 2024 methylene chloride rule under the Toxic Substances Control Act would have banned most uses and required a workplace chemical protection program, but the U.S. Court of Appeals for the Fifth Circuit vacated it in September 2026 and further review is possible. Check the current status of EPA's rules. The OSHA standard applies either way. In July 2025 OSHA proposed changes to the respirator provisions of this standard. OSHA reopened the comment period in July 2026 and held public hearings in August 2026. No final rule had been issued as of October 2026, so check for updates. State plan states may set stricter rules.

Frequently Asked Questions

Can workers use half mask respirators for methylene chloride?

No. The standard prohibits half mask respirators of any type because MC can irritate or damage the eyes.

Does the standard apply to construction?

Yes. It covers general industry, construction and shipyard employment.

How often is medical surveillance repeated?

Within 12 months of the last surveillance for employees 45 or older, and within 36 months for employees younger than 45.