He learned it was toxic when his wife 's hair started falling out .
But Carlson had personal experience with mercury - based fungicides typically used on golf courses : One of his earliest jobs was to mix the stuff by hand .
Carlson learned it was toxic when Carlson 's wife 's hair started falling out .
But Carlson had personal experience with mercury - based fungicides typically used on golf courses : One of his earliest jobs was to mix the stuff by hand .