On February 14, a commercial truck tractor hauling a trailer hit the highway median and rolled onto I-10 in Arizona, outside of Tucson. The deadly collision led to the spill of hazardous materials, which leaked from the commercial truck tractor.

The vehicle was found to be carrying liquid nitric acid, which, according to the Centers for Disease Control and Prevention (CDC), can cause eye and skin irritation, delayed pulmonary edema, pneumonitis, bronchitis and dental erosion depending on the amount and length of exposure. The chemical is frequently used for manufacturing plastics, dyes and ammonium nitrate for fertilizers, HuffPost reported.

The interstate was immediately closed down, and those within a half-mile radius of the incident were immediately evacuated. Those within a mile were told to shelter in place following the collision, although this order was lifted later that night and then reinstated the next morning. The Arizona Department of Public Safety reported that gassing occurred when crews tried to remove the load of nitric acid from the vehicle. The crews were later able to remove the nitric acid and used dirt to mitigate further gassing.

The evacuation order was lifted on the evening of Feb. 15, and the interstate also reopened at 6:45 p.m.

The Arizona Department of Public Safety has directed those who may have been exposed to toxic fumes from the spill to review guidance from Pima County Health Department.

“If an individual has met that 15 minute or more exposure within a mile of the incident and developed respiratory difficulties or new symptoms (wheezing, shortness of breath; difficulty breathing, exacerbations of COPD or asthma) they should seek medical evaluation,” the Pima County Health Department advised. “It is possible that individuals who lived within a mile of the exposure and sheltered in place but were using air exchange that pulled air from the outside may have met this threshold.”

Local residents are also advised to wipe down outdoor equipment with water for homes within a one-mile radius, although the Pima County Health Department noted, “Concentrations in the immediate area of the spill are low or undetectable. Contamination of objects that were left outdoors is unlikely.”

The cause of the collision is under investigation. The latest update from the Arizona Department of Public Safety identified the driver, who was killed in the incident, and reported that Landstar Inway Inc. was the operating authority of the load being hauled.