Hazardous materials and wastes can enter the environment (air, water, and soil) when they are produced, used, and disposed. The impact to the environmental is determined by:

• Characteristics of the material;
• Amount and concentration of the material or chemical;
• Fate and transport of the chemical;
• Exposure pathway (ingested, inhaled, topical, etc.);
• Length of exposure;
• Tolerance and sensitivity of the plants and animals exposed to the hazardous chemical.

Improper handling of hazardous materials can cause the contamination of watercourses, groundwater, land and air. Contamination creates a risk of acute and long term impacts on the health of plants and animals, humans and on natural and agricultural resources. In addition to risks to environmental health (including public health), contamination of land and water can impede economic development by delaying land development and by impacting the quality of water used by agricultural, processing and industrial operations.

Understanding the potential health impacts of chemicals and hazardous substances is important.