Methylene chloride: beware CNS depression and carbon monoxide toxicity
February 23, 2012, 11:46 pm
Methylene Chloride
Fatal Exposure to Methylene Chloride Among Bathtub Refinishers — United States, 2000-2011. MMWR 2012 Feb 24;61:119-22.
Methylene chloride is a halogenated hydrocarbon used as a paint stripper, degreaser, and metal cleaner. It is readily absorbed into the system when inhaled, and can be extremely toxic through a number of different mechanisms. Like most hydrocarbons, it causes CNS depression and cardiotoxicity. In addition, methylene chloride is slowly metabolized through the CYP2E1 hepatic cytochrome P450 pathway to form carbon monoxide. Therefore, delayed carbon monoxide toxicity (onset 4-8 hours after exposure) is a unique feature of methylene chloride exposure.
This investigation from the Centers for Disease Control and Prevention identified 13 deaths in workers using methylene chloride in enclosed, poorly ventilated spaces to strip bathtubs. Five patients had carboxyhemoglobin levels measured — none were remarkably elevated (range: 0 – 5%), making carbon monoxide toxicity an unlikely primary cause of death.
The authors make the following points:
- To minimize skin absorption, workers using methylene chloride should wear butyl rubber or polyvinyl alcohol (not latex) gloves.
- Methylene chloride should not be used unless work areas are well-ventilated and appropriate personal protective equipment is employed.
- In small enclosed spaces such as bathrooms, use of methylene chloride is extremely hazardous — alternative stripping materials should be used.
- Methylene chloride poses a risk not only to professionals but also to do-it-yourselfers.
Katrin Hruska Says:
The European union has banned the use of DCM-based paint strippers by consumers. The ban also applies to professional paint strippers, often small freelance teams, but member nations can allow DCM use by ‘specifically trained professionals under certain strict conditions,’ which would include use of proper protective gear.
The reason for this seems to be evidence of carcinogenicity and the acute toxic effects are believed to be low.
February 29th, 2012