A truck carrying hazardous nitric acid overturned on an Arizona highway, prompting evacuations of the area

By Caitlin O'Kane

February 15, 2023 / 10:31 AM / CBS News

A commercial vehicle carrying extremely hazardous nitric acid was involved in a crash on an Arizona highway, prompting officials to evacuate the immediate area, including the University of Arizona's Science and Tech Park. Officials also ordered residents within a mile of the incident to shelter in place, a measure still in place Wednesday morning.

The truck-tractor hauling a box trailer, carrying the highly corrosive liquid form of nitric acid, rolled over Tuesday evening on Interstate 10 in Tucson, the state's third-largest city. The chemical not only intensifies fires but can cause severe skin burns and eye damage and is fatal if inhaled, according to the National Library of Medicine.

People within a half-mile radius of the incident were evacuated and those within one mile of the incident were directed to shelter in place as the Hazardous Materials Response, Tucson Fire and Police Departments and other local law enforcement agencies responded, the Arizona Department of Public Safety announced at 6:47 p.m.

The shelter-in-place was initially lifted at 8:45 p.m. and residents were told they could run any heaters and air conditioners that bring in outside air again, and the department said it anticipated lifting the evacuation order at 6 a.m. on Wednesday. But at 4:55 a.m., the department re-instated the shelter-in-place and advised anyone within the one-mile perimeter to turn off heaters and conditioners.

Mixing nitric acid with water may generate heat, which increases the concentration of fumes in the air. The water that mixes with it may then become toxic. And while it won't catch fire and does not burn it can produce corrosive or toxic fumes when it is heated.

Nitric acid is used in fertilizers and cleaning products that remove stains or discoloration and can also be used in products that remove grease and in laser printers. It is also used in controlled laboratory settings.

The chemical appears as a red-brown fume when it is a gas and can have a suffocating odor, which is toxic to inhale, according to the library of medicine. Crews closed the road and told motorists to avoid the area as they attempted to remove the load of nitric acid from the commercial vehicle. However, they said gassing occurred, which is visible in photos from the scene.

The driver of the commercial vehicle died during the accident.

CBS News has reached out to the Arizona Department of Public Safety for more information and is awaiting response.

Earlier this month, a toxic train derailment in Ohio forced hundreds of nearby residents to evacuate for several days. A total of 38 rail cars derailed, and another 12 cars were damaged by a fire. Hazardous materials were in 11 of the derailed cars.

Residents were evacuated so crews could release chemicals for a controlled burn.

Ohio Gov. Mike DeWine addressed concerns about the harmful chemicals remaining in the air. After the controlled burn, the Ohio National Guard wearing protective suits measured the air in the area, and no one was allowed back into the area until it was deemed safe.

Caitlin O'Kane is a digital content producer covering trending stories for CBS News and its good news brand, The Uplift.

First published on February 15, 2023 / 10:31 AM

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