Carpenter said the drama began to unfold at 6:30 a.m. when a UTA officer doing a routine sweep of the 1300 South "Ballpark Station" spotted the suspicious package inside the locker. Salt Lake City police responded with a drug-sniffing dog; the canine alerted to the locker, indicating the presence of drugs.
A search warrant was obtained and the dog was deployed once more, but this time did not alert to the locker's interior. The dog may have earlier sensed drug traces within the more general area outside of the locker itself, Carpenter said.
Police then removed the package, and that is when they noticed the hazardous materials label. Hazmat and Salt Lake County bomb squad experts were called while UTA implemented a lock down of the light rail tracks between 900 South and 2100 South.
By 2:30 p.m., the 900 South station had about 200 people waiting for buses to transport them around the closed down section of tracks. Carpenter acknowledged that wait for many was a long one, though the "bus bridge" was up and operating shortly before TRAX service was restored through the 1300 South station.
"Safety of our passengers is always our top priority," he said. "We did have [the bus bridge] going and moved as many as we could, but it always takes some time to activate those. Our major concern then was to gear up for [a disruption] that could possibly extend into the late-afternoon commute, when we have our heaviest traffic."
Carpenter said UTA was attempting to identify and contact the person who rented the locker to determine why he or she was storing the inert and non-combustible argon gas canister there.
Argon gas has many uses, but mostly is used in arc welding and other high-temperature industrial processes. Argon gas also is used in incandescent and fluorescent lighting.