Toxicant 4 : A substance that kills or injures an organism through its chemical pr physical action, or by altering its environment; for example, cyanides, phenols, pesticides, or heavy metals. (Bul D11)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}