Police are appealing for help finding a canister with radioactive material inside stolen from a van in Bacup.
Officers were alerted in the early hours of this morning after the van driver discovered the material was missing.
The Peugeot Panel van was parked up on New Line in Bacup and the canister was taken at some point over the weekend.
The stolen canister is in a yellow case which measures one foot long and police say will be fairly heavy.
Chief Inspector Russ Procter, from Burnley Police, said, “It is important that this material is located as soon as possible.
“I would ask the public, especially in the Rossendale area, to keep an eye out for this canister and if they locate it then to call the police who will come and deal with it.
“I would also appeal direct to the people who have stolen this. They may have no idea what it is that they have in their possession or they may have discarded it somewhere.
“If that is the case then I would ask them to contact us or call CrimeStoppers anonymously.”
Anyone with information is asked to call Lancashire police on 999 or call Crimestoppers, anonymously, on 0800 555111.
The Health Protection Agency is urging anyone coming in contact with the cylinder to leave it where it is and alert the police.
A spokesperson for the agency said: “The radioactive material, believed to be Iridium 192, will not pose a risk to the public if it remains contained in its heavy lead container marked with the radiation trefoil.
“However, if the material is outside of its protection packaging, anyone who has come into prolonged physical contact, such as keeping it in a pocket, should seek medical assistance.
“If you see this package you should immediately inform the police, do not touch it and keep away.”