Myclobutanil

Myclobutanil is a triazole chemical used as a fungicide. It is a steroid demethylation inhibitor, specifically inhibiting ergosterol biosynthesis. Ergosterol is a critical component of fungal cell membranes.
Safety.
When heated, myclobutanil decomposes to produce corrosive and/or toxic fumes, including carbon monoxide, carbon dioxide, hydrogen chloride, hydrogen cyanide, and nitrogen oxides. 
Banned for cannabis cultivation.
Myclobutanil is banned in Canada, Colorado, Washington, Oregon, and Oklahoma for the production of medical and recreational marijuana. In 2014, a Canadian news investigation by The Globe and Mail reported the discovery of myclobutanil in medical marijuana produced by at least one government licensed grower. In September 2019, NBC News commissioned CannaSafe to test THC cartridges for heavy metals, pesticides, and residual solvents like Vitamin E; pesticides, including myclobutanil, was found in products from unlicensed dealers. In Michigan, the current state action limit for myclobutanil is 200 ppb in cannabis products.