Six oil workers were exposed to radiation on a North Sea installation.
The Wood Group employees were contracted by EnQuest to carry out work on the Thistle platform, 125 miles north-east of the Shetland Islands when the incident happened back in December.
The platform was undergoing planned shutdown activities at the time.
The offshore workers were removing a piece of pipework when they were exposed to naturally occurring radioactive material, rig operator EnQuest confirmed.
A spokeswoman for the firm said: “EnQuest can confirm that, in December 2016, during planned shutdown activities on its Thistle platform, six personnel employed by Wood Group under a contract with EnQuest were removing a piece of pipework when they were exposed to low levels of NORM (naturally occurring radioactive material).
“The level of exposure was less than 1% of the level at which it is reportable to the Health and Safety Executive however EnQuest advised the HSE of the matter at the time.
“EnQuest has appropriate control measures in place which are designed to prevent exposure to NORM. Following an investigation, additional precautionary steps have been taken to further ensure that personnel avoid any such exposure.”