14. Dimethylmercury (DMM) Hazard

The importance of wearing the correct protective equipment

14 October, 1997

To: Chairpersons, WHMIS Coordinates/Spill Designates
From: Office of Environmental Health & Safety, University of Alberta
Subject: Dimethylmercury (DMM) Hazard

This letter is to advise all recipients of an incident involving DMM and to provide advice regarding its handling. Earlier this year, a researcher at Dartmouth College died from the toxic effects of DMM poisoning after having been contaminated with the substance. Although uncertainty still exists as to how she was exposed, investigators believe that the exposure probably occurred through skin absorption after spilled DMM penetrated the latex gloves that the researcher was wearing. The researcher in this case was a chemistry professor and a respected authority on the properties and toxic effects of DMM. This accident underscores the need for researchers to ensure that they are properly protected when working with hazardous substances with particular attention given to the choice of protective gloves. For certain chemicals shuch as DMM, latex gloves do not provide adequate protection and may in fact engender a false sense of security.

The following guidelines should be followed whenever working with DMM or other substances of a simialr nature:

1. Understand full the hazards of the substance by referring to the SDS sheet. The MSDS for DMM indicates that the substance is highly toxic through inhalation or skin contact and that suitable protective gloves and clothing must be worn. The SDS does not specify the type of glove required however, therefore the researcher needs to check with the manufacturer to determine if a certain type of glove offers adequate protection. In working with DMM, 4H or Silver Shield liners should be worn under unsupported neoprene, nitrile or similar heavy duty gloves.

2. If possible, substitute a less hazardous substance for the hazardous material.

3. Ensure that written standard operating procedures are available or posted at the job site when working with hazardous substances such as DMM. This should include actions to take in the event of spills, personal contamination and other accidents.

4. Ensure that the hazardous substance is properly contained during storage, use, and disposal.

Please distribute this notice to all laboratory occupants in your department.