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Methylene chloride, also called dichloromethane, is a volatile, colorless liquid with a chloroform-like odor. Methylene chloride is a solvent used in various industrial processes in many different industries: paint stripping, pharmaceutical manufacturing, paint remover manufacturing, metal cleaning and degreasing, adhesives manufacturing and use, polyurethane foam production, film base manufacturing, polycarbonate resin production, and solvent distribution and formulation.
The predominant means of exposure to methylene chloride is inhalation and skin exposure. OSHA considers methylene chloride to be a potential occupational carcinogen. Short-term exposures to high concentrations may cause mental confusion, lightheadedness, nausea, vomiting, and headache. Continued exposure may also cause eye and respiratory tract irritation. Exposure to methylene chloride may make symptoms of angina more severe. Skin exposure to liquid methylene chloride may cause irritation or chemical burns.
Scope
The OSHA methylene chloride standard covers all occupational exposures to methylene chloride in all workplaces.
Compliance point
If your warehouse will be storing or using a product that contains methylene chloride, it’s a good idea to review the safety data sheet for the product. Check the ingredients for your products to see if it contains methylene chloride, also known as dichloromethane, DCM, or MCL. Its Chemical Abstracts Service number (75-09-2) may also be listed on the safety data sheet.
Regulatory citations
- 29 CFR 1910.1052 — Methylene chloride.
Key definitions
- Action level: A concentration of airborne MC of 12.5 parts per million (ppm) calculated as an eight (8)-hour time-weighted average (TWA).
- Authorized person: Any person specifically authorized by the employer and required by work duties to be present in regulated areas, or any person entering such an area as a designated representative of employees for the purpose of exercising the right to observe monitoring and measuring procedures under paragraph (d) of this section, or any other person authorized by the OSH Act or regulations issued under the Act. Director means the Director of the National Institute for Occupational Safety and Health, U.S. Department of Health and Human Services, or designee.
- Emergency: Any occurrence, such as, but not limited to, equipment failure, rupture of containers, or failure of control equipment, which results, or is likely to result in an uncontrolled release of MC. If an incidental release of MC can be controlled by employees such as maintenance personnel at the time of release and in accordance with the leak/spill provisions required by paragraph (f) of this section, it is not considered an emergency as defined by this standard.
- Employee exposure: Exposure to airborne MC which occurs or would occur if the employee were not using respiratory protection.
- Methylene chloride (MC): An organic compound with chemical formula, CH2 Cl2. Its Chemical Abstracts Service Registry Number is 75-09-2. Its molecular weight is 84.9 g/mole.
- Permissible exposure limit or PEL: 25 parts methylene chloride per million parts of air (ppm) as an eight-hour time-weighted average (TWA). This refers to the average exposure during an eight-hour period. Employers must use engineering and work practice controls to limit employee exposures. Respiratory protection must be used in addition if these controls are insufficient to reduce exposures to below the limits.
- Physician or other licensed health care professional: An individual whose legally permitted scope of practice (i.e., license, registration, or certification) allows him or her to independently provide or be delegated the responsibility to provide some or all of the health care services required by paragraph (j) of this section.
- Regulated area: An area, demarcated by the employer, where an employee’s exposure to airborne concentrations of MC exceeds or can reasonably be expected to exceed either the 8-hour TWA PEL or the STEL.
- Symptom: Central nervous system effects such as headaches, disorientation, dizziness, fatigue, and decreased attention span; skin effects such as chapping, erythema, cracked skin, or skin burns; and cardiac effects such as chest pain or shortness of breath.
Summary of requirements
Employers must:
- Survey the operations for methylene chloride.
- Observe the permissible exposure limit or PEL, which is 25 parts methylene chloride per million parts of air (ppm) as an eight-hour time-weighted average (TWA). This refers to the average exposure during an eight-hour period. Employers must use engineering and work practice controls to limit employee exposures. Respiratory protection must be used in addition if these controls are insufficient to reduce exposures to below the limits.
- Establish a regulated area where exposure to airborne concentrations of methylene chloride exceeds or can be expected to exceed either the PEL or the STEL.
- Set-up a monitoring program to obtain adequate information on exposure levels.
- Train employees on hazards and controls of MC.
- Establish a medical surveillance program for all employees exposed to MC.
- Provide hygiene areas for washing and changing clothes.
- Provide engineering and work practice controls where feasible.
- Implement a respiratory protection program meeting the requirements of 1910.134 when exposures are not controlled adequately by engineering and administrative controls.
- Keep exposure and medical records.