Unlikely. Myositis or myopathy are not interchangble. Polymyositis is an autoimmune disease. Not caused by toxins. However, may toxins casn affect muscle. Even drugs like we use for cholesterol issues (statins) can cause a myopathy.
Not directly. Polymyositis is a classic idiopathic (unknown cause) inflammatory muscle disease. There may be a genetic link. Chemicals have not been shown to cause it. Some polymyositis patients also have cancer and cancer can be caused by chemicals.
NO. None of these exposures have been proven to cause polymyositis.