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WPD | Hazardous Waste Management

Solid Waste/Hazardous Waste

Hazardous Waste Management

Revised On: Nov. 13, 2023 - 9:00 a.m.

The management of hazardous waste is governed by the Resource Conservation and Recovery Act (RCRA). Federal and state hazardous waste management regulations apply to most businesses that generate hazardous waste. The following Q&A explains how hazardous waste may affect your business and ADEQ’s role in hazardous waste management.

What is Hazardous Waste?

Hazardous waste is a special category or subset of regulated wastes that businesses generate. There is not a single comprehensive list of hazardous waste that is continuously updated, as hazardous waste identification is a process that involves many steps. For a material to be a hazardous waste, the material must first be a “solid waste.” If you generate a solid waste, you are required to determine whether that material is a hazardous waste. This waste determination must be made the moment a material becomes a solid waste.

The U.S. Environmental Protection Agency (EPA) defines a solid waste as any discarded solid, semisolid, liquid or contained gaseous material that is disposed of, burned incinerated, or recycled. It can be the spent material or byproduct of a manufacturing process or a household item such as a cleaning fluid or battery acid. Recyclable materials or items that can be reclaimed or reused in some way (e.g. distillation of spent solvents, burning used oil for fuel) may also be considered solid waste.

Generally, waste is considered as hazardous by the federal government based on its characteristics. Waste is considered hazardous, if it is:

  • Ignitable — Creates fire under certain conditions, spontaneously combustible, or have a flash point less than 140F (e.g. some paints, degreasers and solvents)
  • Corrosive — Capable of corroding metals or has a high or low pH (e.g. acid or alkaline cleaning fluids, rust removers and battery acid)
  • Reactive or unstable — Can  cause explosions, toxic fumes, gases and vapors when mixed with water or under other conditions, such as heat or pressure (e.g. some cyanides and sulfide-bearing wastes)
  • Toxic — Harmful or fatal when ingested or absorbed, or leaches toxic chemicals into the soil or ground water (e.g. wastes with high concentrations of heavy metals, such as cadmium, lead or mercury)

The EPA also has four lists describing hundreds of specific wastes and waste streams as hazardous (F, K, P, U). These are what is known as listed waste. These wastes have been studied and are known to be harmful to public health and the environment when not managed properly, regardless of their concentrations.

In addition, a mixture of hazardous waste with solid waste (e.g. contaminated motor oil with trash or debris) or wastes derived from the treatment of hazardous waste (e.g. wastewater treatment sludge) may be considered hazardous waste.

Determining Your Requirements

  1. First, look at each of your waste streams and determine whether the waste is hazardous.
  2. Measure how much hazardous waste your business produces each month. This will determine your business' generator category and the management requirements that must be followed.

To determine your generator category, you would measure all quantities of listed and characteristic hazardous waste that are:

  • Generated and accumulated on site for any period of time before disposal or recycling. For example, dry cleaners must count any residue removed from machines, as well as spent cartridge filters.
  • Packaged and transported away from your business. 
  • Placed directly in a regulated treatment or disposal unit at your place of business. 
  • Generated as still bottoms or sludges and removed from product storage tanks. 

Many hazardous wastes are liquids and measured in gallons, not pounds. Liquid hazardous wastes must be converted. Water's specific gravity is 1, and 1 gallon of water weighs 8.34 pounds. So, if you have a 55 gallon drum with 50 gallons of water, the equation looks like this: ((1 x 8.34) x 50) = 417 pounds. We say 50 gallons because you must always remember to leave headspace in a drum. Never fill a container all the way to the top. Replace the "1" with the specific gravity of the chemical you are working with. For example: 98 percent sulfuric has a specific gravity of 1.84. (1.84 x 8.34) = 15.3456 pounds per gallon. Now multiply that by 50 for a 55 gallon drum. (15.3456 x 50) = 767 pounds for a 55 gallon drum.

EPA has established three generator categories, each of which is regulated differently:

  • Very Small Quantity Generators (VSQGs) generate no more than 220 pounds (100 kg) of hazardous waste in any month and store no more than 2,200 pounds (1,000 kg) of hazardous waste at any given time. VSQGs are conditionally exempt from hazardous waste management regulations provided that certain basic requirements are met.
  • Small Quantity Generators (SQGs) generate between 220 and 2,200 pounds (100 and 1,000 kg) of hazardous waste in any month and store no more than 13,228 pounds (6,000 kg) of hazardous waste at any given time. SQGs must comply with EPA and state requirements for managing hazardous waste.
  • Large Quantity Generators (LQGs) generate more than 2,200 pounds (1,000 kg) of hazardous waste in any month. LQGs must comply with more extensive hazardous waste rules.

Some wastes are so dangerous that they are called acutely hazardous wastes. If a business generates or accumulates more than 2.2 pounds (1 kg) of acutely hazardous waste or 220 pounds (100 kg) of acutely hazardous residue, debris, or soil in a calendar month, all of the acutely hazardous waste must be managed according to the regulations applicable to LQGs.

How does ADEQ monitor hazardous waste?

ADEQ is concerned with health and safety issues involving hazardous waste management in Arizona. Under the RCRA, along with state statutes and codes, ADEQ has the authority to monitor and direct businesses that may generate, transport or dispose of hazardous waste in Arizona.

The Waste Programs Division implements state and federal hazardous waste laws pursuant to delegation from the EPA. The division is responsible for effectively implementing standards for the safe generation, management, treatment, storage and disposal of hazardous waste. Specific responsibilities include:

  • Inspections and Compliance — Conducting routine, follow-up, and initial compliance inspections and responding to public complaints and other agency referrals to ensure that hazardous wastes are safely managed and properly disposed
  • Permits and Plan Review — Permitting facilities that treat, store or dispose of hazardous waste and reviewing required plans and monitoring reports
  • Outreach and Compliance Assistance — Educating and reaching out to the regulated community and the general public
  • Pollution Prevention — Managing ADEQ’s pollution prevention (P2) program and other activities aimed at eliminating or reducing the use of toxic substances and the generation of hazardous wastes
  • Remediation and Cleanup — Providing oversight and coordination of investigations and cleanups of contaminated sites
  • Information Management — Issuing EPA identification numbers, and evaluating annual facility registration and generation self-reporting forms submitted through myDEQ | Learn More >*

* Due to E-manifest reporting requirements, all manifests are now required to be submitted to EPA by receiving facilities through RCRAInfo | Visit Site >