The Phoenix Fire Department hazardous material team is investigating after a woman reported finding uranium in north Phoenix on Monday evening.
A fire department representative said that a woman was cleaning out her deceased father-in-law's garage near Glendale and 19th avenues when she found what she believed to be uranium inside a three-inch thick lead case.
Emergency crews from the Arizona Radiological Regulatory Agency determined the substance is uranium-238, the most common isotope found in the environment.
According to the Institute for Institute for Energy and Environmental Research, U-238 poses little health hazard as long as it remains outside of the body. If inhaled or ingested, it can pose an increased risk for bone and lung cancer, among other negative health effects.
Uranium-238 also cannot sustain a nuclear chain reaction on its own, which it is not the isotope used for nuclear weapons.
Officials said the father-in-law is a chemist but were not sure how or why the element was in his possession.
No injuries have been reported. Hazardous materials crews tested the air and ambient radioactivity, but nothing was out of the ordinary.
State regulators took possession of the uranium for disposal, according to a news release from the Phoenix Fire Department.