Hazardous materials personnel were sent to the Huntsman Chemical plant in the Atwater Villager area of Los Angeles after a vapor cloud formed inside the facility Friday morning.

An automatic fire alarm activated at the location around 8:40 a.m. after a mixing vessel overheated and a pressure relief valve was initiated as it was designed to, the Los Angeles Fire Department said in a post on its Facebook page.

“Approximately 200 personnel from multiple buildings within the complex self-evacuated prior to LAFD arrival and had no medical complaints,” the fire department’s statement said. “Some residents of neighboring areas reported a foul odor and were advised to shelter-in-place (closing all doors and windows) or to voluntarily evacuate south of the incident.”

The HAZMAT crew learned that a one-component epoxy system called “Reninfusion 8610” was in the vessel at the time of the incident. An investigation into the cause of the incident is underway.