Feb 17: The driver may have experienced a medical issue before the crash on Tuesday, officials said during a news conference Thursday afternoon, adding that intoxication was not a factor. The rollover caused the trailer shell to crack open, sending plumes of the volatile chemical into the air. Following the accident, the road was closed in both directions and area residents were told to shelter in place. After more than a day, the road reopened and the shelter in place order was lifted Wednesday evening.

Feb 15: Officials in southern Arizona have issued evacuation and shelter-in-place orders after a truck carrying hazardous chemicals overturned on a local freeway.
The Department of Public Safety closed a portion of Interstate on Tuesday after a tractor trailer hauling nitric acid rolled over and began leaking the caustic material.
The driver of the leaking truck died at the scene. An investigation into the collision is ongoing.
An evacuation order was issued for the half-mile perimeter around the crash site, while those within a mile were told to shelter in place. Those within the one-mile perimeter were advised to turn off any heaters or air conditioning units “that bring in outside air” until further notice.
The shelter-in-place order was temporarily lifted Tuesday evening, but reinstated early Wednesday following “temporary setbacks” in the recovery and mitigation efforts overnight “due to weather conditions,” according to authorities.
The xxx said “gassing occurred” as crews tried to remove the hazardous load from the overturned truck.
“Crews have now removed the material from the truck and are utilizing dirt to mitigate further off gassing,” the department said Wednesday morning.
The new shelter-in-place order was extended to a three-mile perimeter around the incident location, and those who evacuated were told to stay out of the area.
Officials asked people to turn off their heaters and air conditioners again, as well.
“Unified Command will actively monitor within these boundaries to ensure public safety and assess the need for possible changes to existing evacuations and shelter-in-place orders,” the xxx said.
Motorists have been told to avoid the area as officials “anticipate an extensive closure” of the roadway, the xxx said.
Nitric acid is colorless as a liquid, but creates red or yellow fumes “with an acrid odor” when it becomes a gas, according to xxx. It is often used to make fertilizers, dyes and explosives.
Exposure to the “highly corrosive” compound can lead to irritated eyes, skin, and mucous membranes and breathing problems such as delayed pulmonary edema, pneumonitis and bronchitis, the xxx said.