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Americium-241, an isotope that emits gamma and beta rays as it decays, is found in homes around the world in an unassuming device: a fire alarm.

"It emits both beta rays and gamma rays so if you have it close to you, you could either end up with skin damage including skin burns," the state's Chief Health Officer Andy Robertson warned.

Some of these sensors collect particles on a filter and then shine beta rays through them to measure mass.

Potential sources of exposure, the agency found, included inhaling or ingesting uranium dust or fumes as well as gamma or beta rays while handling or working near the depleted uranium.

"Since they emit beta rays we weren't able to detect them until recently. Specific tools were necessary and we couldn't afford them," says Suzuki.