Legal Definitions - hazardous substance

A hazardous substance refers to any material, chemical, or mixture that, due to its inherent properties, poses a significant risk to human health, safety, or the environment when released or improperly managed. These properties can include toxicity, corrosivity, flammability, or reactivity. Environmental laws often classify such substances to ensure they are handled, stored, transported, and disposed of with specific precautions to prevent harm.

Here are some examples illustrating the application of this term:

• Industrial Chemical Spill: A chemical manufacturing plant experiences a leak in a storage tank, releasing several hundred gallons of concentrated sulfuric acid onto the factory grounds and into a nearby stream. Sulfuric acid is a hazardous substance because it is highly corrosive, capable of causing severe burns to humans and significant damage to aquatic ecosystems and soil. Its uncontrolled release triggers immediate emergency response protocols and environmental cleanup requirements under hazardous substance regulations.

• Contaminated Construction Site: During the excavation for a new building project, construction workers uncover buried drums containing old pesticides and industrial solvents left by a previous occupant decades ago. Laboratory analysis confirms the presence of chemicals known to be carcinogenic and persistent in the environment. These chemicals are classified as hazardous substances due to their long-term toxicity and potential to contaminate groundwater, necessitating specialized removal and disposal procedures to protect public health and the environment.

• Transportation Accident: A freight train derails, and one of its cars, carrying anhydrous ammonia (a chemical used in fertilizers), is breached, releasing a large plume of the gas into the atmosphere. Anhydrous ammonia is a hazardous substance because it is highly toxic by inhalation and corrosive to skin and eyes. The release requires immediate evacuation of nearby communities and a coordinated emergency response to contain the gas and mitigate its dangerous effects on human health and the surrounding area.