Waste Trends

Nuclear Waste | Hazardous Waste | Investment Recovery | Polychlorinated Biphenyls (PCB) Management | Spills | Toxic Release Inventory

Nuclear Waste

Like all nuclear power plants, Palo Verde produces nuclear waste in the form of spent fuel, high-level waste and low-level waste such as used protective clothing, filters, resins and other contaminated items.

Palo Verde has been aggressively moving spent fuel from spent fuel pools to dry cask storage. Dry cask storage is a safe, low-maintenance and effective interim storage method for spent fuel until the U.S. Department of Energy meets its responsibility to provide a permanent spent fuel and high-level nuclear waste storage facility. The minimal quantities of high level waste are stored in spent fuel pools.

In addition to the on-site maintenance of spent fuel and high-level waste, Palo Verde manages its low-level waste by packaging the waste in proper containers and shipping the waste for disposal in “permitted disposal facilities.”

Hazardous Waste

APS has been aggressively reducing hazardous waste for a number of years, from 193 tons per year in 2003 to 9.14 tons in 2016. The trend is down, except when episodic events occur, such as a fire that occurred at the Elden Substation which contained lithium batteries that caught fire on November 26, 2012. APS responded by remediating the area outside of the energy storage unit and secured the unit until it was released for disposal. The site became an episodic large quantity generator during disposal of the batteries in 2014, which is why there is an increase in waste generation for that year. In 2015, this trend continued its downward trajectory. The majority of the hazardous waste generated and shipped in 2016 was from Four Corners due to activities associated with the decommissioning of Units 1-3. A total of 3,838 lbs. of hazardous waste was shipped from Four Corners alone, and consisting mostly of lead-based paint abatement waste. In prior years, a number of our facilities were large-quantity generators of hazardous waste. Our goal is to have all of our facilities be either small-quantity generators or conditionally exempt small-quantity generators of hazardous waste. All of our hazardous wastes are transported by permitted companies to EPA-permitted hazardous-waste disposal facilities located in the United States.

Investment Recovery

APS’s Investment Recovery group is a leader in corporate recycling and landfill reduction. Investment Recovery recycles material through both specialized streams (such as scrap metal and E-waste) as well as comingled, single-stream recycling of common materials. We also continue to track waste diverted through the APS forestry program. This is done through capturing quantities of vegetation that are removed and are able to be mulched.

Polychlorinated Biphenyls (PCB) Management

For a number of years, APS has had an aggressive program in place to manage PCB and PCB-contaminated equipment. APS has been successful in reducing the use of PCBs in electrical equipment by targeting suspected equipment based on manufacturer name and serial numbers. The PCB status of our electrical equipment is tracked in an electronic database, which is available across the company. Between 2000 and 2016, APS removed 17,543 pieces of equipment from the distribution and substation systems, resulting in the disposal of over 4 million pounds of PCB-containing material. APS continues to proactively identify and manage PCB-containing equipment.


The only reportable spill of hazardous materials in 2016 occurred at our Palo Verde Generating Station, where approximately 8,000 gallons of sodium hypochlorite was accidently released. The spill entered soil, rocks and a small gunite ditch. The spill was isolated and immediately cleaned up.

Toxic Release Inventory

APS is required to report lawful releases of chemicals listed by the EPA under the federal Toxic Release Inventory (TRI) program. Our reportable releases under the TRI program primarily include air emissions from power plants or coal ash disposal. Our reporting facilities are the Four Corners Power Plant in Farmington, New Mexico, and the Cholla Power Plant in Joseph City, Arizona.

The majority of these releases are captured by pollution control equipment or are contained within the coal ash by-product, which is either recycled for beneficial use or properly managed in coal ash surface impoundments and landfills.