Crews are investigating an explosion that happened at Florida's Eglin Air Force Base. The base has implemented a shelter in place order between Eglin Boulevard to Van Matre is in place as a safety measure. In a tweet, Eglin has instructed residents in that area to turn their HVAC system off. Eglin Air Force Base tweeted that the incident happened at McKinley Climatic Lab a little before 10 a.m. "The source of the smoke has been identified as methyl chloride. Avoid contact with the smoke if possible," said Ilka Cole, public affairs specalist for Eglin Air Force Base. The Okaloosa County Sheriff's Office (OCSO) said in a Facebook post the surrounding area has been evacuated and a 1,000 foot cordon has been established. Eglin tweeted "the smoke may contain methyl chloride". The OCSO reports visible smoke does not pose a health hazard to the general public. The cause of the explosion is under an investigation.