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Methylene Chloride

Methylene chloride, also called dichloromethane, is a volatile, colorless liquid with a chloroform-like odor. Methylene chloride is used in various industrial processes, in many different industries including paint stripping, pharmaceutical manufacturing, paint remover manufacturing, and metal cleaning and degreasing. The most common means of exposure to methylene chloride is inhalation and skin exposure. OSHA considers methylene chloride to be a potential occupational carcinogen.

OSHA Standards

Exposures to methylene chloride are addressed in specific standards for general industry, shipyard employment and the construction industry. This section highlights OSHA standards, preambles to final rules (background to final rules), Federal Registers (rules, proposed rules, and notices), directives (instructions for compliance officers), and standard interpretations (official letters of interpretation of the standards) related to methylene chloride. Twenty-five states, Puerto Rico and the Virgin Islands have OSHA-approved State Plans and have adopted their own standards and enforcement policies. For the most part, these States adopt standards that are identical to Federal OSHA. However, some States have adopted different standards applicable to this topic or may have different enforcement policies.

General Industry (29 CFR 1910)

Shipyard Employment (29 CFR 1915)

Construction Industry (29 CFR 1926)

Preambles to Final Rules

Federal Registers

Directives

Standard Interpretations

Hazard Recognition

Methylene chloride is a solvent which is used in many different types of work activities, such as paint stripping, polyurethane foam manufacturing, cleaning, and degreasing. Employees exposed to methylene chloride are at increased risk of developing cancer, adverse effects on the heart, central nervous system and liver, and skin or eye irritation. Exposure may occur through inhalation, by absorption through the skin, or through contact with the skin. The following references aid in recognizing methylene chloride hazards in the workplace.

  • Methylene Chloride. National Institute for Occupational Safety and Health (NIOSH), (1994, May). Provides an Immediately Dangerous to Life or Health (IDLH) document that includes acute toxicity data for methylene chloride.

  • Methylene Chloride. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication 86-114 (Current Intelligence Bulletin No. 46), (1986, April). Describes a study where mice that were exposed to methylene chloride in air, developed cancers (alveolar/bronchiolar carcinomas) and tumors (alveolar/bronchiolar adenomas) of the lung, and cancers (hepatocellular carcinomas) of the liver.

  • Criteria for a Recommended Standard: Occupational Exposure to Methylene Chloride. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication 76-138, (1976, March). Includes biological effects, exposure, and work practice information for methylene chloride.

  • TOXNET for Dichloromethane. The National Library of Medicine.

  • Report on Carcinogens (RoC). US Department of Health and Human Services (DHHS), National Toxicology Program (NTP). Identifies and discusses agents, substances, mixtures, or exposure circumstances that may pose a health hazard due to their carcinogenicity. The listing of substances in the RoC only indicates a potential hazard and does not establish the exposure conditions that would pose cancer risks to individuals.
    • Dichloromethane [139 KB PDF, 3 pages]. NTP classification: Reasonably anticipated to be a human carcinogen
  • International Agency for Research on Cancer (IARC) Monographs on the Evaluation of Carcinogenic Risks for Humans [225 KB PDF, 66 pages]. World Health Organization (WHO). IARC Classification: Possibly carcinogenic to humans (Group 2B).

  • Toxicological Profile for Methylene Chloride. Agency for Toxic Substances and Disease Registry (ATSDR), (2000, September). Provides exposure risks, exposure limits, and health effects for methylene chloride.

  • ToxFAQs™ for Methylene Chloride. Agency for Toxic Substances and Disease Registry (ATSDR), (2001, February). Summarizes the properties and health effects for methylene chloride.

  • Dichloromethane (CASRN 75-09-2). Environmental Protection Agency (EPA), Integrated Risk Information System (IRIS). Discusses the health effects of dichloromethane.

  • Methylene Chloride (Dichloromethane). Environmental Protection Agency, (Revised January 2000). Lists methylene chloride as a Hazardous Air Pollutant (HAP) under the National Emissions Standard Hazardous Air Pollutants section of its Clean Air Act.

  • Methylene Chloride [620 KB PDF, 6 pages]. New Jersey Department of Health and Senior Services, Hazardous Substance Fact Sheet, (Revised October 2008). Provides a summary source of information of all potential and most severe health hazards that may result from methylene chloride exposure.

  • International Chemical Safety Cards: Dichloromethane. National Institute for Occupational Safety and Health (NIOSH), (2000, December 4). Summarizes essential health and safety information on methylene chloride.

Exposure Evaluation

Monitoring employee exposures to methylene chloride enables employers to identify the sources of methylene chloride and select appropriate exposure controls. OSHA's methylene chloride standard requires that all facilities using methylene chloride monitor employee exposures. The following references aid in evaluating methylene chloride exposures in the workplace.

  • Methylene Chloride. OSHA Publication 3144-06R, (2003). Also available as a 556 KB PDF, 26 pages. Provides general information regarding methylene chloride exposure limit information, control measures, and other OSHA assistance information.

  • Methylene Chloride Facts No. 1 - Exposure Monitoring Requirements. OSHA, (1998). Provides only general information on monitoring requirements and should not be considered to be a complete summary of the methylene chloride related monitoring requirements.

  • Chemical Sampling Information. OSHA. Presents, in concise form, data on a large number of chemical substances that may be encountered in industrial hygiene investigations. Basic reference for industrial hygienists engaged in OSHA field activity.
  • Occupational Chemical Database. OSHA maintains this chemical database as a convenient reference for the occupational safety and health community. It compiles information from several government agencies and organizations. This database originally was developed by OSHA in cooperation with EPA.

Analytical Methods

OSHA

OSHA has developed and validated methods for use by the Salt Lake Technical Center (SLTC) laboratory. The following method has been adopted by many laboratories for the analysis of chemical compounds. Exposures should be evaluated with standard total dust sampling techniques for comparison to the OSHA permissible exposure limits (PEL).

Possible Solutions

Controlling the exposure to methylene chloride may be done through engineering controls, administrative actions, and personal protective equipment. Engineering controls include isolating the source and using ventilation systems. Administrative actions include limiting the worker's exposure time and washing facilities. Personal protective equipment includes wearing the proper respiratory protection and clothing. The following resources contain information to help control exposures.

  • Methylene Chloride Small Entity Compliance Guide Fact Sheets. OSHA. Discusses monitoring requirements, suggested engineering and work practice controls, substitutes, respirator use, protective equipment, and compliance schedules for various small businesses.  A collection of 11 documents that provide suggestions for controls and work practices in nine industries and operations.

  • Preventing Worker Deaths from Paint Strippers Containing Methylene Chloride. California Department of Public Health, Occupational Health Branch (2014, January). Provides a number of useful resources to help workers and employers select safer paint stripping products and employ proper personal protection, respirators and safe work practices. The site also has education and training materials.

  • NIOSH Pocket Guide to Chemical Hazards. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 2005-149, (2007, September). Provides a physical description, exposure limits, measurement method, personal protection and sanitation, first aid, respirator recommendations, exposure routes, symptoms, target organs, and cancer sites.
  • Occupational Health Guidelines for Chemical Hazards. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication 81-123, (1981, January). Contains information on identification, physical and chemical properties, health hazards, exposure limits, exposure sources and control methods, monitoring, personal hygiene, storage, spills and leaks, and personal protective equipment.

  • Questions and Answers - Methylene Chloride Control in Furniture Stripping. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 93-133, (1993, May). Answers commonly asked questions about the hazards from exposure to methylene chloride. Also describes approaches to controlling methylene chloride exposure during the most common furniture stripping processes.

  • Assisting Furniture Strippers in Reducing the Risk from Methylene Chloride Stripping Formulations. National Institute for Occupational Safety and Health (NIOSH) In-Depth Survey Report, (1999, March 26). Provides a report detailing the effectiveness of several different ventilation systems in an effort to reduce methylene chloride exposures in furniture stripping operations. None of the ventilation systems were effective in controlling exposures below the OSHA PEL of 25 ppm.

Additional Information

Related Safety and Health Topics Pages

Training

Other Resources

  • Methylene Chloride. National Institute for Occupational Safety and Health (NIOSH) Workplace Safety and Health Topic.

  • Methylene Chloride. National Institute of Standards and Technology (NIST) Chemistry WebBook. A comprehensive database with highly technical information, including thermochemical, thermophysical, and ion energetics data.

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