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In GHS do we Pass, or Pass on, or Punt the methylene chloride (MeCl)!

It is just not in paint thinner products. Despite widespread recognition of harm, methylene chloride is not adequately regulated. Dichloromethane (DCM, or methylene chloride) is an organic compound with the formula CH2Cl2. This colorless, volatile liquid with a moderately sweet aroma is widely used as a solvent. Although it is not miscible with water, it is miscible with many organic solvents. DCM is produced by treating either chloromethane or methane with chlorine gas at 400–500 °C. At these temperatures, both methane and chloromethane undergo a series of reactions producing progressively more chlorinated products.

CAS Registry No.: 75-09-2

Other Names: Dichloromethane, Methylene dichloride, DCM

Main Uses: Solvent, paint stripper, chemical and food processing.

Appearance: Colourless liquid.

Odour: Sweet

Canadian TDG: UN1593

Numerous poisonings and deaths have been reported over several decades among workers and consumers using furniture strippers or other products containing methylene chloride in unventilated areas. Easily inhaled, methylene chloride converts to carbon monoxide once inside the body—making it especially dangerous for people with heart or lung disease, and pregnant women. Furthermore, several federal, state, and international agencies have identified methylene chloride as a cancer-causing substance. Unlike the poisonings, cancer in people caused by methylene chloride can take years to develop and is more difficult to document. Despite decades of knowledge about these toxic health effects, methylene chloride remains poorly regulated. Though some federal and state standards exist, none of these standards are strong enough to protect worker or public health and none address the chemical’s entire lifecycle.

Methylene Chloride is found in consumer products such as spray shoe polish, water repellents, spot removers, wood floor and panel cleaners, adhesive removers, lubricants, wood stains, varnishes and finishes, paint strippers and graffiti removal products, rust removers, glass frosting/artificial snow, and some automotive parts cleaning products.

Main Routes of Exposure: Inhalation; skin contact; eye contact.

  • Inhalation: TOXIC, can cause death. Can irritate the nose and throat. Can harm the nervous system. Symptoms may include headache, nausea, dizziness, drowsiness and confusion. Methylene chloride form carbon monoxide in the body. Can harm the blood (decreased ability to carry oxygen).
  • Skin Contact: SKIN IRRITANT. Causes moderate to severe irritation. Symptoms include pain, redness, and swelling. Can be absorbed through the skin, but harmful effects are not expected.
  • Eye Contact: EYE IRRITANT. Causes moderate to severe irritation. Symptoms include sore, red eyes, and tearing.
  • Ingestion: If large amounts are ingested: can burn the lips, tongue, throat and stomach.
  • Effects of Long-Term (Chronic) Exposure: Can cause dry, red, cracked skin (dermatitis) following skin contact. At high concentrations: May harm the nervous system. May aggravate existing heart conditions. Conclusions cannot be drawn from the limited studies available.
  • Carcinogenicity: Possible carcinogen. May cause cancer based on animal information.

International Agency for Research on Cancer (IARC): Group 2B – Possibly carcinogenic to humans.

American Conference for Governmental Industrial Hygienists (ACGIH): A3 – Confirmed animal carcinogen.

Flammable Properties: Can ignite if strongly heated.

Suitable Extinguishing Media: Carbon dioxide, dry chemical powder, appropriate foam, water spray or fog. Foam manufacturers should be consulted for recommendations regarding types of foams and application rates.

Specific Hazards Arising from the Chemical: Forms corrosive chemicals on contact with water. Vapour may accumulate in hazardous amounts in low-lying areas especially inside confined spaces, resulting in a toxicity hazard. Closed containers may rupture violently when heated releasing contents. In a fire, the following hazardous materials may be generated: very toxic carbon monoxide, carbon dioxide; corrosive hydrogen chloride; corrosive chlorine; corrosive phosgene.

What are the stability and reactivity hazards of methylene chloride?

  • Chemical Stability: Normally stable.
  • Conditions to Avoid: High temperatures. (above 100°C) Open flames, sparks, static discharge, heat and other ignition sources. High energy sources, e.g. welding arcs. Hot surfaces.
  • Incompatible Materials: Increased risk of fire and explosion on contact with: strong oxidizing agents (e.g. perchloric acid), methanol, alkali metals (e.g. sodium or potassium). Not corrosive to: aluminum alloys, stainless steel.
  • Hazardous Decomposition Products: Prolonged contact with water may form corrosive hydrochloric acid.

What are accidental release measures for methylene chloride?

Personal Precautions: Evacuate the area immediately. Isolate the hazard area. Keep out unnecessary and unprotected personnel. Eliminate all ignition sources. Use grounded, explosion-proof equipment.

Methods for Containment and Clean-up: Do not touch spilled material. Stop or reduce leak if safe to do so. Ventilate the area to prevent the gas from accumulating, especially in confined spaces. Small spills or leaks: contain and soak up spill with absorbent that does not react with spilled product. Place used absorbent into suitable, covered, labelled containers for disposal. Contaminated absorbent poses the same hazard as the spilled product. Large spills or leaks: contact emergency services and manufacturer/supplier for advice.

Handling: Before handling, it is important that all engineering controls are operating and that protective equipment requirements and personal hygiene measures are being followed. Only trained personnel should work with this product. In event of a spill or leak, immediately put on escape-type respirator and exit the area. Immediately report leaks, spills or failures of the safety equipment (e.g. ventilation system). Avoid generating vapours or mists. Prevent accidental contact with incompatible chemicals. Do not use near welding operations or other high energy sources. Do not weld, cut or perform hot work on empty container until all traces of product have been removed.

Storage: Store in an area that is: cool, dry, well-ventilated, out of direct sunlight and away from heat and ignition sources, separate from incompatible materials. Keep amount in storage to a minimum. Store in the original, labelled, shipping container. Avoid bulk storage indoors.

The European Union to pull methylene chloride paint strippers from general use in 2011. For reasons that aren’t clear, regulatory agencies in the United States and Canada have not followed suit—or even required better warnings—despite decades of evidence about the dangers

Industries where methylene chloride is found

In the work place, it is most often used as an aerosol propellant, a degreaser in manufacturing, a paint stripper, and a polyurethane foam blowing agent. It is also an extraction solvent for spices, caffeine, and hops. It is also used in nail salons as an artificial nail solvent.

Exposure and health risks

Exposure to methylene chloride from consumer products occurs when a person breathes the vapors given off by the product or from direct contact of the skin with liquid material. The highest exposures usually occur in workplaces where the chemical is used in large volumes over long periods of time. Methylene chloride is also frequently found as a contaminant at hazardous waste sites, so people living near these areas may be more highly exposed. Once inhaled or absorbed into the body, methylene chloride is converted to carbon monoxide. Since carbon monoxide interferes with oxygen delivery, methylene chloride can make angina (chest pain) and other heart symptoms worse in people with heart disease. People with lung conditions, smokers, and people who are overweight or pregnant also may be more sensitive to methylene chloride. When inhaled or absorbed through the skin, methylene chloride can reach the developing fetus through the placenta and it also can enter breast milk. Methylene chloride affects the nervous system (brain) and can cause headaches, dizziness, nausea, clumsiness, drowsiness, and other effects like those of being drunk. Effects on the nervous system can be long-lasting and possibly permanent if exposures are high and if they occur frequently over months or years. Methylene chloride causes cancer in laboratory animals and potentially can cause cancer in humans. Methylene chloride causes lung and liver tumors, and mammary (breast) tumors in animal studies.

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