A major southern gas pipeline exploded Monday afternoon in Alabama, killing one worker and injuring five others.

The explosion occurred in rural Shelby County when a contract crew hit the pipeline with a trackhoe, igniting gasoline, pipeline operator Colonial told Reuters in an e-mailed statement late on Monday. The blast "sent flames and thick black smoke soaring over the forest," the Associated Press reported. The resulting fires consumed 31 acres and continue to burn, according to a statement from the company, which shut down its two mainlines after the explosion.

Local station WBRC cited Gov. Robert Bentley in reporting that "forestry crews have helped set up a three-mile perimeter around the explosion site and authorities are evacuating all civilians within that perimeter."

See footage below from WAFF-48:

And photos were posted on social media:

Colonial Pipeline reports one fatality from the explosion, 5 hospitalized w/burns. Praying for them all this AM-GRB https://t.co/n1FwQqjeE8 pic.twitter.com/EBJ44VNa80

— Gov. Robert Bentley (@GovernorBentley) November 1, 2016

A major pipeline explosion in west Shelby County west of Helena. Possibly related to the Colonial Pipeline spill pic.twitter.com/jqWnPxAgZ6

— Alexander Hansen (@AlexanderXV) October 31, 2016

NEW IMAGES: 1 dead in Colonial Pipeline explosion https://t.co/SnDGMDFNp5 pic.twitter.com/fMqFrDvSd0

— WBRC FOX6 News (@WBRCnews) November 1, 2016

The explosion happened about five miles west from the site of a recent Colonial Pipeline gasoline leak, as Al.com noted. That September incident, too—the fifth in the state this year—forced Colonial to shut down its lines, making this the second time in as many months that the company has done so.

It is also the latest in a series of pipeline incidents, which come amid intense debate over pipeline safety and fossil fuel infrastructure.

As such, many social media users posted about the explosion along with the hashtag #NoDAPL, indicating their opposition to the controversial Dakota Access Pipeline.

Now imagine this happening in your water source and you get an idea of why Standing Rock Sioux are #NoDAPL https://t.co/rfitqYxjNq

— Steve (@SteveBriscoe6) November 1, 2016

The Colonial pipeline in Alabama just exploded, injuring at least 7.

THIS is what #NoDAPL activists worry about. pic.twitter.com/BOaUY0gOEk

— Fusion (@Fusion) October 31, 2016

#ColonialPipeline explosion underscores the inherent danger of pipelines. Explosions, leaks, spills... that's what pipelines do. #NoDAPL pic.twitter.com/Ji3Di66yxM

— Fight Climate Denial (@fightdenial) October 31, 2016

"Because pipelines leak, pollute & explode," tweeted one user.