A sign indicating radioactive material is shown in Anaheim, California, 2011.

BAGHDAD — Iraq is searching for “highly dangerous” radioactive material stolen last year, according to an environment ministry document and seven security, environmental and provincial officials who fear it could be used as a weapon if acquired by ISIS.

The material, stored in a protective case the size of a laptop computer, went missing in November from a storage facility near the southern city of Basra belonging to U.S. oilfield services company Weatherford (WFT.N), the document obtained by Reuters showed and officials confirmed.

A spokesman for Iraq’s environment ministry said he could not discuss the issue, citing national security concerns. A Weatherford spokesman in Iraq declined to comment, and the company’s Houston headquarters did not respond to repeated requests for comment.

The material, which uses gamma rays to test flaws in materials used for oil and gas pipelines in a process called industrial gamma radiography, is owned by Istanbul-based SGS Turkey, according to the document and officials.

An SGS official in Iraq declined to comment and referred Reuters to its Turkish headquarters, which did not respond to phone calls.

The document, dated Nov. 30 and addressed to the ministry’s Centre for Prevention of Radiation, describes “the theft of a highly dangerous radioactive source of Ir-192 with highly radioactive activity belonging to SGS from a depot belonging to Weatherford in the Rafidhia area of Basra province.”

A senior environment ministry official based in Basra, who declined to be named as he is not authorized to speak publicly, told Reuters the device contained up to 10 grams (0.35 ounces) of Ir-192 “capsules”, a radioactive isotope of iridium also used to treat cancer.

The material is classed as a Category 2 radioactive source by the International Atomic Energy Agency, meaning if not managed properly it could cause permanent injury to a person in close proximity to it for minutes or hours, and could be fatal to someone exposed for a period of hours to days.

How harmful exposure can be is determined by a number of factors such as the material’s strength and age, which Reuters could not immediately determine. The ministry document said it posed a risk of bodily and environmental harm as well as a national security threat.

Large quantities of Ir-192 have gone missing before in the United States, Britain and other countries, stoking fears among security officials that it could be used to make a dirty bomb.

A dirty bomb combines nuclear material with conventional explosives to contaminate an area with radiation, in contrast to a nuclear weapon, which uses nuclear fission to trigger a vastly more powerful blast.

“We are afraid the radioactive element will fall into the hands of Daesh,” said a senior security official with knowledge of the theft, using an Arabic acronym for ISIS.

“They could simply attach it to explosives to make a dirty bomb,” said the official, who works at the interior ministry and spoke on condition of anonymity as he is also not authorized to speak publicly.