The flames are incredible to see, but this fire produces a dangerous gas.

This video was shot by Worland Fire Protection in Wyoming. They were called out to a recycling facility about a fire. When they got there, they realized it was a sulfur mound that was burning.

The fire looks surreal, but firefighters warn that burning sulfur creates sulfur dioxide, which is a hazardous gas.

Video of the burning sulfur has gone viral. It was posted July 8, and already has more than 34,000 shares on Facebook.