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  for Metal Finishing since 1989
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Methylene chlroide - Ensuring a Safe Working Environment

Methylene chloride is used in this industry. What are the available methods to keep the vapor concentration of this solvent to be below the TLV value?

If scrubber (absorption columns) are used, should water be used as the scrubbing liquid? Or should a solution of a chemical be used?

Boon Keat
- Singapore
2000

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Use CH₂Cl₂ under good ventilation (i.e., fume cupboard or canopy)

Water can be use in scrubber but please bear in mind that it has limited solubility of CH₂Cl₂, which is an organic solvent. It is rare to use some other chemicals other than water and NaOH/KOH solution in the scrubber.

Danny Lau
Hong Kong
2000

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Boon,

Methylene Chloride is a known carcinogen and ozone depleter. In our plant in order to provide a safe and healthy work environment for plant associates and the public, this material was phased out at least nine years ago by finding and substituting an alternative solvent. It requires more work and experimentation in finding an environmentally friendly replacement, but will pay dividends in providing a healthy and safe environment. If a good alternative is found, it may very well eliminate the need for installing "end of pipe" treatment processes and it's associated operations and maintenance costs. Neil

Neil E. Hatfield
- Franklin Park Illinois USA
2001

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Ed. note, Feb. 24, 2012: Per www.cbc.ca/news/health/story/2012/02/24/bathtub-refinishing-deaths.html
"Methylene chloride ... has been linked to the deaths of 13 workers refinishing bathtubs in the United States...
To use products containing methylene chloride safely, work areas must be well-ventilated, and when levels of methylene chloride exceed recommended exposure limits, workers must use protective equipment ...
The finding has prompted the CDC to warn ... public health agencies, manufacturers and trade groups to 'communicate the extreme hazards' of the use of the chemical -- also known as dichloromethane -- to employers, workers and the public."

Boon,

l. No, don't use water to scrub the fumes. I don't think that that is of any use whatsoever as you are dealing with a pure solvent/sic. gas.

2. Possibly the only way to 'remove' it is to burn the fumes prior to exhausting them to atmosphere ... which might or might not cause other problems, I don't know.

Freeman Newton [deceased]
(It is our sad duty to advise that Freeman passed away
April 21, 2012. R.I.P. old friend).
2001