Chemical company Orica has been forced to temporarily close a warehouse at Villawood in Sydney's west after workers became unwell from an unidentified odour.
Police, HAZMAT crews and paramedics were this morning called to the Villawood site where dozens of chemicals are temporarily stored before being trucked to outside businesses.
Several employees reported feeling unwell and having a metallic taste in their mouths.
They were examined by paramedics and cleared, though seven workers have since been referred for further medical tests.
Orica spokesman Simon Westaway says up to 4,000 chemicals are stored at the depot and the company is working with the Environmental Protection Authority to identify the source of the problem.
"We've temporarily suspended operations as we seek to determine the source of the odour," he said.
Mr Westaway says with the warehouse being based in an industrial area within the suburb, it is possible the odour came from outside.
It is the latest bad publicity for Orica, which is under scrutiny over concerns about .