A portion of Interstate 10 running through Arizona remains closed outside Tucson on Wednesday morning, a day after a deadly crash caused a hazardous material leak and forced evacuations nearby.
Residents within a half mile (800 meters) of the crash on I-10 southeast of downtown Tucson were ordered to leave, and those within 3 miles (4.8 kilometers) were told to shelter in place after liquid nitric acid was determined to be leaking from the truck tractor pulling a box trailer, the Arizona Department of Public Safety said.
A 1-mile (1.6 kilometers) shelter-in-place order was lifted Tuesday night, but officials reinstated it early Wednesday morning, saying gassing occurred as crews tried to remove the load and later expanded the perimeter. Area residents were told to turn off heaters and air conditioning systems that bring in outside air. The area would be monitored to assess the need for possible changes to these orders, officials said, noting that those who evacuated should expect to be displaced until midday.
The weather temporarily impeded hazardous material recovery and mitigation efforts overnight. But officials said Wednesday morning that the material had been removed from the truck, and crews were using dirt to mitigate further off-gassing.
The driver of the truck was killed, the department said, but few other details were released.
The agency warned motorists in the Tucson area should anticipate impacts on their Wednesday morning commute in and around I-10.
“This will be an extended closure,” it said in a tweet Tuesday evening.
The University of Arizona Tech Park was among the areas evacuated. Some schoolchildren in Rita Ranch were among those who sheltered in place, the Arizona Daily Star reported. Officials canceled classes at several nearby schools on Wednesday.
Nitric acid is used to make ammonium nitrate for fertilizers and in the manufacture of plastics and dyes.
The Centers for Disease Control and Prevention's website says nitric acid is a highly corrosive, colorless liquid with yellow or red fumes and can cause an acrid smell.
It says exposure to nitric acid can irritate the eyes, skin and mucous membranes. Depending on the dosage, it also can cause delayed pulmonary edema, pneumonitis, bronchitis and dental erosion.
This hazardous crash comes as Ohio residents continue to raise concerns about the release of toxic chemicals on board a freight train that derailed Feb. 3 and left 50 cars in a fiery, mangled mess. There were no injuries but officials later ordered the evacuation of the immediate area. Residents are worried about the potential health impacts from the wreckage.