Phosphine carries the chemical formula of PH3. The concentration of this compound constantly alters in our environment. Phosphine is an important agricultural fumigant with pulmonary and systemic toxicity that is generated on site as a gas given off by moisture coming in contact with solid form aluminum or zinc phosphide (e.g., in grain storage facilities or railway grain transport cars, where bystanders can be exposed). Phosphine also has industrial applications, particularly in the production of microelectronics. Symptoms such as diarrhea, nausea and vomiting, tightness of the chest, cough, headache, and dizziness have been reported in workers exposed intermittently to concentrations up to 35 ppm.

Cupric oxalate is used as a catalyst for organic reactions and in seed treatment as a repellent for birds and rodents. Cupric oxalate is on the Hazardous substance list, it may cause liver damage, allergy, irritation, etc.