Warning: Arsenic in our forests

The B.C. Forests Ministry has produced a map of areas containing thousands of trees that the public and loggers are urged to avoid because of arsenic residue from the application of a pine-beetle pesticide no longer used in Canada.

Monosodium methanearsenate, or MSMA, was widely used in B.C.'s northern and Interior regions from the mid-1980s until 2004 with assurances at the time that the pesticide, sold under the trade name Glowon, posed little threat to the environment or to human health. By 2005, MSMA was no longer in use in Canada after the manufacturer allowed its permit to expire.

In 2006, the U.S. Environmental Protection Agency announced its intention to not re-register MSMA as an organic arsenic pesticide because it posed a cancer risk because of its potential to "transform to a more toxic inorganic form of arsenic in soil with subsequent transport to drinking water." MSMA continues to be sold in the U.S.

A map is nearly completed along with precautionary details and can be viewed at www.for.gov.bc./hfp/health/MSMA.htm#links.