Covanta Hempstead is a waste-to-energy plant in Uniondale, New York operated by Covanta. It is the tallest structure in Nassau County, and the fourth largest power generation facility on Long Island by net energy generated.

The original plant on the site opened in 1979 on land formerly part of Mitchel Air Force Base. It used an untested wet refuse-derived fuel process, and operated only for about a year before it was shut down due to mechanical failures, labor and payment disputes, unpleasant odors that could be smelled two miles (3.2 km) away, and concerns about toxic dioxin emissions.

After the original operator defaulted on its bonds, the plant was sold, demolished, and rebuilt as a new plant using a traditional dry process, opening in 1989.

Covanta Hempstead is the fourth largest power generation facility on Long Island by net energy generated in 2020, behind Northport Power Station, Caithness Long Island Energy Center, and E. F. Barrett Power Station. However, it ranks thirteenth on Long Island by nameplate capacity. It consists of a single waste-to-energy unit.^[1] It is operated by Covanta, and the electricity generated at the plant is distributed across Long Island via the Long Island Power Authority's electrical transmission network.^[2][3]

Its 382-foot (116 m)^[4] smokestack is the tallest structure in Nassau County, and among the tallest on Long Island.^[5] It is a easily visible from the Meadowbrook State Parkway, which passes directly in front of it.^[6][7]

The facility has contracts with the Town of Hempstead, the Village of Garden City, and the Town of North Hempstead to incinerate their municipal solid waste. As of 2022, the plant produces 500–750 tons of incinerator bottom ash and fly ash each day, which is taken to the Town of Brookhaven landfill in North Bellport, New York.^[6][7]

This article's "criticism" or "controversy" section may compromise the article's neutrality. (February 2024)

In 2013, a whistleblower case was filed by a former employee, Patrick Fahey, who stated that Covanta had failed to properly store and treat ash before disposal since 2006, in violation of federal and state environmental laws and potentially exposing the surrounding community to hazardous substances. Covanta denied the allegations, and LIPA, the Village of Garden City and the Town of Hempstead all declined involvement in the lawsuit, with Garden City stating that the whistleblower suit is without merit, and preferring to settle with Covanta.^[6][7]

In 2022, workers at nearby New York TRACON had complained about ash from the plant damaging their cars; this and other concerns led the Federal Aviation Administration to engage the Occupational Safety and Health Administration and the Centers for Disease Control and Prevention about potential impacts to worker health.^[6]

In 2024, the New York Department of Environmental Conservation (NYSDEC) found Covanta to be in violation of environmental state law after a multi-year investigation into ash management activities prompted by complaints from the Brookhaven Landfill Action and Remediation Group (BLARG).^[21][22][23] NYSDEC completed its review of documents submitted by Jenner & Block LLP related to the management of ash residue at Covanta Hempstead. These documents included Covanta's engineering calculations, instructions to the crane operator, residue/ash truck tracking log sheets, ash management plans, ash testing results, and various e-mail correspondence provided by the Covanta Hempstead’s attorney as well as DEC’s historical files.^[22] It was noted that the ash sent out to the Ash Residue Management Plan (“ARMP”) for sampling and analysis was not representative of all ash sent out for disposal, and that the ash was in fact in violation of ash handling practices, posing toxic environmental threats to the Long Island community.^[22]