The health effects of coming into contact with a radioactive capsule no bigger than a coin that was lost in Western Australia -- and has since been found -- could potentially be severe, according to experts.
Caesium-137 is a human-made fission project often used in radiological laboratories as well as in industrial settings, such as within gauges in mining operations, Angela Di Fulvio, an assistant professor of nuclear engineering at the University of Illinois Urbana-Champaign, told ABC News.
The tiny capsule filled with Caesium-137, at 8 millimeters tall and 6 millimeters in diameter, was found on the roadside of a remote highway Wednesday afternoon, six days after it went missing in Western Australia.
"When you consider the scope of the research area, locating this object was a monumental challenge, the search groups have quite literally found the needle in the haystack," state Emergency Services Minister Stephen Dawson said during a press conference Wednesday, according to Reuters.
Emergency responders and radiation specialists were frantically searching for the capsule along a 22-mile busy freight route in the regions of Pilbara, Midwest Gascoyne, Goldfields-Midlands and Perth Metropolitan, according to the Department of Fire and Emergency Services Western Australia.
Search parties drove north and south along the Great Northern Highway at slow speeds in hopes of finding the capsule, the DFES said in a statement. DFES specialist search teams also used radiation survey meters to detect the gamma rays and radiation levels to try and locate the capsule, according to the agency.
The capsule was lost during transportation from the Rio Tinto mine in north Newman to the northeastern suburbs of Perth, an 870-mile journey.
Officials believe a screw became loose inside the large lead-line gauge, and that the unit fell through a hole, The Associated Press reported. The capsule was packaged in accordance with radiation safety regulations, officials said.
The capsule contained materials that are "a million times more active" than those used in a lab, Di Fulvio said, describing it as a "very active" source. At 1.665 millisieverts per hour, the unit of measurement used for radiation, coming into 1 meter of the source is comparable to about 17 chest X-rays, Di Fulvio said.
Prolonged close exposure to the capsule -- for instance, if someone were to have picked it up and put it in their pocket -- could cause severe, and even potentially deadly, health effects, within hours, Di Fulvio said.
Erythema, or reddening of the skin, would be among the first symptoms, and the severity of the effects increases dramatically with exposure time, she added.
Exposure to the radioactive substance could also cause radiation burns or radiation sickness, according to the DFES.
Officials warned the public to stay at least 5 meters, or about 16 feet, away from it, and not to touch it, if they saw something that could be the material.
Andrew Robertson, Chief Health Officer of Western Australia, said officials are concerned that an unsuspecting party would pick up the object, not knowing what it is, and keep it, the AP reported.
"I'm confident that they are going to be able to find it," she said, prior to the capsule's discovery.
The capsule had been packaged on Jan. 10 to be sent to Perth for repair, and the package containing the capsule arrived in Perth on Jan. 16, where it was unloaded and stored in the licensed service provider's secure radiation store, according to the DFES.
When the gauge was unpacked for inspection on Jan. 25, the inspectors found that the gauge was broken apart, the DFES said. One of the four mounting bolts was missing, as were the source of the radiation itself and all screws on the gauge.
Police said the case of the missing capsule was an accident and that they likely will not file criminal charges, the AP reported. An investigation will look into how the capsule was packaged and transported.