Firefighters were called out after smoke was detected at a factory on a Highland industrial estate.
Fire crews were called to carbon fibre manufacturing factory SGL Technic at Muir of Ord at about 04:15.
Site director Stephen Easton later said there appeared to have been an issue with thermal oil overheating but there was no actual fire.
The Scottish Fire and Rescue Service said four appliances and a support unit were sent to the scene.
Mr Easton added: "There was an incident early this morning at our Muir of Ord site.
"It appears to have been an issue with thermal oil overheating and while there was smoke, there was no actual fire. Everybody was evacuated and there were no injuries.
"The emergency services arrived on scene very quickly and we would like to thank them for their prompt response.
"An investigation into the cause is under way but the spillage has been contained completely within the site and we are now undertaking a clean-up operation. We hope to be back to normal as soon as possible."