An accidental plume of gas sent emergency crews rushing to Howmet Aerospace’s manufacturing facility on Harvard Avenue in Cuyahoga Heights, where the affected area was evacuated as a precaution and a few workers were treated on site over concerns about inhalation. The release happened while a contractor working out of a tanker truck was collecting waste nitric acid, a chemical the plant uses in its metal-etching operations.
According to News 5 Cleveland, Rob Morrison said the incident happened around 11 a.m. Crews responded quickly to the property, clearing the area before turning their attention to checking for any residual effects lingering after the release.
Medical Checks and a Cautious Clean-Up
A handful of people received on-site medical attention due to concerns about inhalation, Morrison said. The evacuation was a precaution, and crews remained on scene afterward working through the area for any lingering contamination.
Morrison does not anticipate any impact on production beyond Wednesday, the station reported.
Nitric Acid Incidents Elsewhere in Ohio
Nitric acid releases have rattled other Ohio communities before. In June 2025, about 3,000 gallons of nitric acid leaked from a 5,000-gallon tank at Austin Powder’s Red Diamond plant in Vinton County, according to 10TV. The chemical reaction in that tank produced nitrogen oxide gas that vented into the air, creating an orangish-brown plume that prompted evacuations of workers and nearby residents, including those living in the village of Zaleski.
No injuries were reported in the Vinton County leak, and the Ohio EPA later said the plume had dissipated, 10TV noted. On October 21, 2026, the City of Toledo ordered evacuations in North Toledo after a tank explosion and chemical release, according to the City of Toledo. The Associated Press reported that the Ohio EPA attributed that leak to an error made while material was being transferred, though the agency did not elaborate further.
What Remains Unclear
Ohio law requires facility owners and operators to notify authorities about certain releases of hazardous substances, extremely hazardous substances or oil that meet reportable-quantity thresholds set under state rules, except for releases that expose people solely within the facility site, according to the Ohio Revised Code.
