Chinese officials say that potentially deadly radioactive material lost in north-western Shaanxi province may have been found at a steel mill.
Officials told the BBC that they had detected what may be the missing Caesium-137, adding that it may have been melted down.
The Caesium-137, encased in lead, was lost this week when workers at a cement plant demolished an old factory.
The material was part of a measuring instrument and is extremely dangerous.
Caesium-137 is a radioactive isotope, formed mainly through nuclear fission. The smallest amount can cause infertility, cancer and even death.
Eight trucks worth of scrap gathered at the disused factory in Tongchuan city were sold to a local steel mill, according to official news agency Xinhua.
Local environmental officials told the BBC they were mounting a clean-up operation at the mill in Fuping county.
The BBC's Quentin Sommerville in Beijing says China has an appalling record on industrial safety - there are around 30 cases of radioactive material being lost every year.
Last July, a farmer in Shaanxi province was arrested after he stole a similar radioactive container and attempted to sell it for scrap.