EPA, contractors resume cleanup at former Diaz site in Holley

Photo from EPA: This photo shows phase 1 of the heater wells at the former Diaz Chemical site on Jackson Street in Holley.

Posted 20 September 2023 at 2:58 pm

Press Release, Environmental Protection Agency

HOLLEY – The U.S. Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers (USACE) is overseeing treatment of contaminated groundwater and soil at the at the Diaz Chemical Corporation Superfund site in Holley.

In July 2023, contractors completed repairs and restarted the treatment process which was shut down in December 2021 because excessive steam was escaping from the well field. The contractors repaired the surface seals of over 200 heater wells and capped the well field with concrete.

The treatment is projected to take up to four years to clean up the remaining contamination at the site. After the cleanup is completed, the contractors will remove the treatment equipment and regrade the site to make sure that it has proper drainage and will re-plant vegetation to prevent erosion.

The thermal treatment system uses heat to convert the contaminants in the soil and groundwater into vapors, which are captured through an extensive vacuum-based extraction system. The extraction wells capture and convey the vapors to a system that treats the vapors by compression, cooling, condensation, and by using granular activated carbon. The system will operate 24 hours a day, seven days a week.

Pilot Program

In 2018, EPA initiated a pilot program, overseeing the construction and operation of a small-scale system to treat approximately 10% of the contaminated soil and groundwater on the former plant grounds at the site.

Under EPA and USACE oversight, USACE’s contractor built the first phase of the system, which began operating in August 2021. Based on the success of this pilot system, EPA and USACE determined that a larger system should be constructed to treat the rest of the contamination on the remaining 1.5 acres of the site property and that the system should be constructed in two phases.

Noise Reduction

The equipment used to heat the soil and capture the vapors generates constant noise. Noise levels are monitored daily at the Diaz Chemical property line and the noise produced at the site must not exceed 65 decibels during overnight hours, which is equivalent to the sound from a normal conversation.

To ensure that the noise is as low as possible, the contractor installed the piping in a way to reduce noise. The contractor is also installing noise absorbing blankets at select locations to reduce the daytime and nighttime noise levels.

Odor Reduction

Heating soil can also produce odors. Organic compounds become vapors as soil temperatures increase. Although all potentially harmful compounds are captured and treated, the treated vapors may still have an odor. The vapors released from the treatment system are tested for the presence of harmful compounds using air monitoring equipment placed around the perimeter of the property. The contractor monitors the air 24 hours a day, seven days a week. As an additional measure to reduce the odor on the site, the contractor removed and disposed of several tons of contaminated concrete from the site.

Pipe failure during testing

In December 2022, after completing repairs and before restarting the treatment system, the contractor used an air compressor to pressurize and test the system. After a couple of minutes of operation, an approximately 120-foot 6-inch PVC pipe in the treatment building became over-pressurized because of a closed valve and failed along its entire length.

No personnel were injured when the pipe ruptured. The contractor replaced the piping, which is made of different material, modified its pressure testing procedures, and repaired the damage in the treatment building.


The Diaz Chemical Superfund site includes the five-acre former Diaz Chemical Corporation facility located at 40 Jackson Street in the Village of Holley, New York. Diaz Chemical manufactured specialty organic chemicals for the agricultural, pharmaceutical, photographic, color and dye, and personal care products industries. The facility released chemicals into the environment from 1975 to 2002.

A reactor vessel overheated in a process building in January 2002 causing its safety valve to rupture. Approximately 75 gallons of a chemical mixture was released through a roof stack vent. The release was a mixture of steam, toluene, and 2‐chloro‐6‐fluorophenol, as well as related chemicals. The mixture landed on properties in the residential neighborhood immediately next to the facility and was visible as red-colored droplets. As a result of the release, several residents voluntarily relocated to area hotels.

The New York State Department of Environmental Conservation and EPA sampled indoor air, soil, interior surfaces, and household items in the affected neighborhood. The data indicated that there were no immediate or short-term threats to people’s health.

In 2002, NYSDEC required the continued operation of a groundwater extraction and treatment system via a trench which Diaz Chemical installed under NYSDEC oversight at the Diaz Chemical facility as an interim measure in 1995. This system provided partial containment of the groundwater contaminant plume.

Diaz Chemical filed for bankruptcy and abandoned the facility in 2003, leaving behind large volumes of chemicals in drums and tanks. EPA removed these chemicals and dismantled the Diaz Chemical production buildings between 2003 and 2007. EPA placed the site on the National Priorities List in 2004.

With assistance from USACE, and under the Uniform Relocation Assistance and Real Property Acquisition Act, EPA purchased eight houses among the affected properties and provided the owners of those homes with relocation assistance. In addition, two individual tenants were assisted with relocating into new rental locations.

EPA performed a study to determine the nature and extent of contamination, assess potential risks to people’s health and the environment, and develop, screen, and evaluate alternative treatment technologies. Based on the study, EPA determined that site-related contamination did not exist in the surrounding residential area and, therefore, a neighborhood cleanup was not necessary.

EPA selected a cleanup plan for the site in September 2012 under federal law that included thermal treatment of the contaminated soil and groundwater at the Diaz Chemical property and natural processes to address the groundwater contamination downgradient of the source areas. The cleanup plan also included building demolition to allow access to contaminated soil at the site.

EPA transferred the eight properties to the Village of Holley Development Corporation (VHDC) in June 2017. Working with a local realtor and law firm, VHDC sold the houses in September 2017 and shared the proceeds with EPA.