All monitored concentrations were 0.50 ppm or greater. Fire officials and representatives of Cooperative Plating determined that the gases were being emitted from the mixed acid waste tank. The emissions were presumed to be the result of a chemical reaction, caused by the combining of nitric acid, sulfuric acid and iron. The acid mixture had recently been added to the tank, which contained a sludge made up of iron and other metals. The Fire Department decided to let the reaction run its course, and did not attempt to add chemicals or water to stop the air emissions.
Nitrogen oxides are the primary component of photo-chemical smog.
Airborne nitrogen dioxide has been shown to form nitric acid vapor, and airborne sulfur dioxide has been shown to form sulfuric acid vapor. Emissions from the plating facility may have, therefore, contained limited amounts of nitric or sulfuric acid vapor. A REL represents the level of exposure to an airborne chemical that is considered to be safe for the general public, including sensitive sub-populations, for limited periods of time. Data collected by the Fire Department indicate that concentrations of NO2 near the plating facility remained above the REL for several hours. Some people in the area therefore may have experienced respiratory or eye irritation.