The Diaz Chemical Corporation site is a five-acre former specialty chemical manufacturing facility in Holley, New York. It was added to the National Priorities List on July 22, 2004, after years of spills and releases dating to around 1975. A 2002 reactor vessel overheat released roughly 75 gallons of chemicals, including toluene and 2-chloro-6-fluorophenol, causing health symptoms in nearby neighborhoods. The company later filed for bankruptcy and abandoned the site, leaving EPA to lead cleanup.
Groundwater across the site contains volatile organic compounds (VOCs), a broad class of carbon-based chemicals that easily evaporate. Specific VOCs present include benzene, vinyl chloride, trichloroethene, tetrachloroethene, ethylbenzene, o-xylene, 1,2-dichloroethane, cis-1,2-dichloroethene, 1,2-dibromoethane, 1,2-dibromo-3-chloropropane, and selenium. Soil and building structures contain polycyclic aromatic hydrocarbons (PAHs), including benzo(a)pyrene and several related compounds. Both groups of contaminants are the focus of ongoing EPA cleanup actions.
Between 2003 and 2007, EPA removed more than 8,000 drums and 112,000 gallons of hazardous waste, decontaminated over 100 reactor vessels and storage tanks, and dismantled more than 51,000 feet of piping. Eight residential properties were relocated and sold in 2017. EPA also sampled air, soil, and indoor surfaces in the surrounding neighborhood and installed vapor mitigation systems in homes where needed. The site is organized into two operable units. Operable Unit 1 addressed permanent relocation of nearby residents, a remedy selected in 2005. Operable Unit 2 covers the entire site and uses in-situ thermal treatment (heating contaminated soil and groundwater underground to remove contaminants), along with demolition, soil cover, off-gas treatment, institutional controls, and offsite disposal. Phase 1 thermal treatment ran from 2018 until a 2021 shutdown for repairs, then restarted. Phase 2 treatment began in June 2021 to address the remaining 90 percent of contamination. Post-remediation soil samples were collected in March 2024. Additional remedial actions are estimated to continue through late 2027 or early 2028.
A five-year review completed in March 2022 found that the cleanup plan is expected to protect human health and the environment once complete. Human exposure to contamination is currently under control, with no unacceptable exposure pathways identified. However, EPA has not yet determined whether contaminated groundwater migration has been stabilized, because sufficient data are not yet available. Physical construction is not yet complete, and the site has not been deleted from the National Priorities List.
Community members can get involved through EPA's Community Involvement Program, which encourages public participation throughout the cleanup process. Site documents are available in person at EPA's Superfund Records Center at 290 Broadway, 18th floor, in New York City, and at the Community Free Library at 86 Public Square in Holley. The Community Involvement Coordinator and Remedial Project Manager are available to answer questions.
