A tiny but dangerous radioactive capsule that sparked an urgent, days-long search after it went missing in Western Australia has now been found, officials there said Wednesday.

Western Australia Emergency Services Minister Stephen Dawson said in a news conference that the capsule was found by an emergency search team on Wednesday morning about 30 miles south of the mining town of Newman.

Authorities said they did not believe anyone had come into contact with the capsule or been harmed by the toxic substance inside it during the days it was lost in the remote Australian outback.

The capsule — which is less than a third of an inch long — contains cesium-137, a radioactive material that emergency services warn can “cause radiation burns or radiation sickness.”

“This is an extraordinary result,” Dawson said, highlighting authorities’ “relentless search over the past six days” to find the capsule. “The search group have quite literally found the needle in the haystack.”

Rio Tinto, the mining giant that operates the mine from where the capsule was traveling when it was lost, thanked Western Australian authorities for locating it and said it would investigate what happened.

Cesium-137 is a radioactive material used in gauges for mining, one of the main industries in resource-rich Western Australia. Exposure to the material can cause increased risk of cancer, radiation burns, acute radiation sickness and potentially death, according to the U.S. Centers for Disease Control and Prevention.

Emergency services first publicly reported the capsule missing late Friday and issued a hazardous materials warning. But they said it could have been lost a couple of weeks before that. It departed Rio Tinto’s Gudai-Darri iron ore mine in Western Australia on Jan. 12 and was thought to have arrived at its destination, a suburb near Perth, the state’s most populous city, on Jan. 16. Its disappearance was discovered on Jan. 25 when it was missing from the package it was transported in, with the gauge inside “broken apart” with screws and a bolt missing, the department said.

Officials said they believe the capsule fell off the back of a truck while in transit. It was discovered Wednesday just 2 meters (6.5 feet) from the northbound roadside edge of the Great Northern Highway, according to Fire and Emergency Services Commissioner Darren Klemm.

A search team from the Australian Nuclear Science and Technology Organization and the Department of Fire and Emergency Services were driving down the highway at about 40 miles per hour when specialized equipment picked up a radiation signal being emitted by the missing capsule, Klemm said. The search team then located the capsule with portable equipment, he added.

Now that the capsule has been located, it will be placed into a lead container to protect those tasked with transporting it from radiation and taken to a secure location near Newman overnight. Its ultimate destination is a WA Health Department facility in Perth, Klemm said. Authorities will survey the site where it was found to make sure no radioactive material leaked from the capsule — though Klemm said that was “extremely unlikely.”

The loss of the capsule sparked an outcry in Western Australia, with locals and officials questioning how radioactive material could have gone missing in the first place.

The outcry deepened when it emerged that the maximum single financial penalty for failing to properly store, package and transport radioactive material in Western Australia is about $700, the Australian Broadcasting Corporation reported. Australian Prime Minister Anthony Albanese said the capsule “shouldn’t have been lost, that’s the first thing. And second, yeah of course that figure is ridiculously low.”

Rio Tinto’s chief executive for iron ore, Simon Trott, apologized for the incident on Sunday and said the company was supporting the search. On Wednesday, he thanked authorities for locating the capsule and vowed to thoroughly investigate what happened.

“While the recovery of the capsule is a great testament to the skill and tenacity of the search team, the fact is it should never have been lost in the first place. I’d like to apologise to the wider community of Western Australia for the concern it has generated,” Trott said in a statement.

“This sort of incident is extremely rare in our industry, which is why we need to investigate it thoroughly and learn what we can to ensure it doesn’t happen again,” he added. “As part of our investigation, we will be assessing whether our processes and protocols, including the use of specialist contractors to package and transport radioactive materials, are appropriate.”

The Western Australia Department of Health said it would also be investigating the incident, and would submit a report to ministerial authorities.

Western Australia Chief Health Officer Andy Robertson said Wednesday that his department would be leading the investigation and said he had the power to prosecute anyone found responsible under the Australian Radiation Protection and Nuclear Safety Act.

Robertson said officers from the Department of Health will conduct the investigation, working with other agencies, and “will be looking at all aspects of this particular event, including the preparation of the gauge for movement, the transport of the gauge, its receipt, the notification of the department.” He said the process “will take a number of weeks.”

Robertson praised the speed of the search process, adding that while the capsule was “tiny” and “difficult to find,” it had nonetheless posed “a significant public health risk.”

“Western Australians can sleep better tonight,” Dawson, the emergency services minister, added.