TUALATIN, Ore. -- Six people were sent to nearby hospitals after a reported mechanical problem created "oxygen deprivation" about 4 a.m. Tuesday inside Lam Research.

All six people were released from hospitals within a few hours. They were not exposed to a toxic chemical, according to Tualatin Valley Fire & Rescue.

The cause was initially thought to be a leak of sulfur hexaflouride, an odorless gas. However, TVF&R later said an unidentified external smell was the likely cause of employee discomfort.

The workers at the semiconductor plant at 11361 SW Leveton Drive who were taken to hospitals complained of upper respiratory issues, including runny noses, coughing and wheezing.

A hazmat team was dispatched to the scene. Lam said the odor was not coming from their facility and is currently working with the Oregon Department of Environmental Quality to investigate the source of the smell.