The former Motorola semiconductor manufacturing plant in Phoenix, Arizona sits at the center of a Superfund site stretching roughly seven miles west toward Sky Harbor Airport. Motorola discovered a leaking underground storage tank in 1982, which triggered investigations that found widespread soil and groundwater contamination from solvents used in chip manufacturing. The site also includes the former 118-acre Honeywell International aerospace facility. EPA added the site to the National Priorities List on October 4, 1989.
Contaminants in groundwater include chlorinated solvents such as trichloroethene, tetrachloroethene, 1,1,1-trichloroethane, and various dichloroethanes and dichloroethenes. Groundwater in the more extensively contaminated operable unit also contains arsenic, cadmium, chromium, lead, benzene, carbon tetrachloride, and chlorinated methanes. Soil contamination includes carbon tetrachloride, tetrachloroethene, trichloroethene, and ethylbenzene. Dense non-aqueous phase liquids have seeped into bedrock, making full cleanup more difficult.
Cleanup is organized into multiple operable units. An on-site soil gas and groundwater recovery system has run since 1992, and a second treatment system using carbon adsorption and ultraviolet oxidation began in 2001. A biologically enhanced soil vapor extraction system removed over four million pounds of petroleum hydrocarbons by 2012. Vapor intrusion mitigation systems have been installed at 16 residential buildings and one commercial building. Two of the four operable units have completed their remedial actions. The third operable unit received a Record of Decision in September 2025, with remedial design expected to begin in late 2027. The fourth unit, covering the Honeywell area, is still in the feasibility study phase. Groundwater contamination is still migrating and physical construction is not yet complete across all units.
EPA's most recent five-year review, completed in September 2021, found that response actions match the selected remedy. However, EPA cannot confirm full protectiveness until it addresses dense non-aqueous phase liquid mitigation, selects an end use for treated groundwater, and increases groundwater extraction. The next five-year review is estimated for September to November 2026. As of December 2024, 27 businesses operate at the site, employing 797 people and generating about $292.6 million in annual sales.
Community members can stay involved through the Community Information Group. A meeting was scheduled for Wednesday, April 8, 2026 at the Balsz School District Board Room, 4825 E Roosevelt St., Phoenix, AZ. The session included an open house followed by a hybrid presentation with cleanup updates. The slideshow presentation from that meeting can be viewed on the EPA's official profile page for this site. Review documents are posted on EPA's website and held at the EPA Superfund Records Center in San Francisco and the Burton Barr Central Library in Phoenix.
