Public Herald has found that since 1948, in the name of conservation, the Montana government has been using a poison linked to Parkinson’s disease in lakes, ponds, and rivers across the state. And that EPA and state agencies have not fully disclosed its risk to human health. FWP records obtained by Public Herald show Montana agencies have applied rotenone 253 times at more than 200 different water bodies, to an estimated length of 533 miles of surface water.