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Types of Hazardous Waste

Waste is any solid, liquid, or contained gaseous material that is disposed of, burned, incinerated, or recycled. Wastes are considered hazardous when they exhibit at least one of four characteristics or appear on one of four EPA lists. 

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Characteristic hazardous wastes exhibit one or more of the following characteristics:

Ignitable: Wastes that easily catch fire when exposed to heat. A waste with a flash point below 140°F is considered hazardous. This information is typically available on safety data sheets or from product suppliers (e.g., solvents and some paints).

Corrosive: Wastes that can corrode metal or have a very low or high pH. A waste with a pH less than or equal to two or greater than or equal to 12.5 is considered hazardous (e.g., or caustic cleaners, battery acid, and rust removers).

Reactive: Wastes that are unstable, explosive, and/or emit toxic gases (e.g., cyanides or sulfide-bearing waste).

Toxic: Wastes that can cause injury or death if swallowed, inhaled, or absorbed through the skin or eyes, or can leach into soil or ground water when disposed of on land (e.g., heavy metals such as lead or mercury).

Listed hazardous wastes appear on any of four lists issued by EPA: F-List, K-List, P-List, or U-List.

Some of these wastes (e.g., some pesticides can be fatal to humans in small doses) are so dangerous that they are called Acute Hazardous Wastes.

Safety data sheets, product supplier information, and analytical testing can help determine the characteristics and constituents of waste. Compare waste to the characteristics and listed chemicals that make waste hazardous. DEQ staff can also help determine whether your waste meets the hazardous criteria.

If you generate hazardous waste, you must comply with these steps:

  • Determine your generator size category based on the amount of waste generated in a month.
  • Comply with storage quantity and time limit requirements.
  • Appropriately treat or dispose of the waste.

See DEQ’s Hazardous Waste Determinations fact sheet.

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Hazardous Waste Bureau Chief

Natalie K. Walker
(208) 373-0506

Hazardous Waste Compliance and Enforcement Supervisor

Caroline Moores
(208) 373-0149

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