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WATCH: AZDPS press conference on I-10 nitric acid spill

Cleanup efforts at the site of a nitric acid spill on I-10 between Kolb and Rita Roads in the Tucson area Tuesday, Feb. 14.
Posted at 12:28 PM, Feb 16, 2023

TUCSON, Ariz. (KGUN) — After a little more than a day of closures along I-10 and cleanup of a hazardous nitric acid spill, traffic is again flowing and the shelter-in-place order for people nearby has been lifted.

Tuesday afternoon around 2:43 p.m., a semi truck carrying canisters of nitric acid overturned in the median on I-10 between South Kolb and South Rita Roads, sending clouds of reddish fumes into the air.

Shortly after, Arizona Department of Public Safety (AZDPS) closed I-10 in both directions, diverting traffic off the Interstate and resulting in traffic backups that would last into the following day.

Later that evening, AZDPS confirmed the driver, whose identity has not been released, had died. As of Thursday morning, authorities have not yet provided details on the cause of the crash.

KGUN 9 livestream of press conference by the Arizona Department of Public Safety Thursday afternoon:

Within a short period of the spill, a shelter-in-place order was issued for surrounding businesses and communities. Anyone within a mile of the crash was told to turn off any air conditioning, heating or other system that would bring outside air in.

AZDPS's Unified Command evacuated people within a half-mile perimeter of the crash, including workers in the UA Tech Park and guests and a nearby hotel.

By Wednesday morning, AZDPS said they were expanding the shelter-in-place order to a three-mile perimeter, and the Pima County Health Department issued health guidance to those who had been exposed to fumes from the spill for a duration longer than fifteen minutes.

As of Wednesday evening, AZDPS announced the re-opening of the Interstate in both direction. It also rescinded the evacuation and shelter-in-place orders.


Five Vail Unified School District school were impacted by the shelter-in-place orders, and were expected to close Wednesday as a result. Early Wednesday, District Superintendent John Carruth told KGUN 9 announced cancellation of classes for the entire district, due to the heavy traffic and impacts on pick ups-and drop-offs.

"We're also working with county officials on what this looks like as far as mitigation, if any is needed. This isn't an issue that just impacts a school. It also impacts every resident in that area,"Carruth told KGUN 9.

In addition to the spill-related I-10 closure, another deadly wreck early Wednesday near I-10 and Wilmot resulted in an additional traffic diversion at Craycroft Road, just west of the initial freeway closure.

School returned as scheduled Thursday morning.


Anne Simmons is the digital executive producer for KGUN 9. Anne got her start in television while still a student at the University of Arizona. Before joining KGUN, she managed multiple public access television stations in the Bay Area and has worked as a video producer in the non-profit sector. Share your story ideas and important issues with Anne by emailing or by connecting on Instagram, Twitter or LinkedIn.