UPPER MARLBORO, Md. (WJZ) — After battling a blaze for more than 12 hours, firefighters in Prince George’s County finally stop it.

Jessica Kartalija has more on what made this fire so difficult.

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It took them so long because firefighters tell WJZ they had so many factors working against them.

Bright orange flames lit up the night sky in a rural part of Upper Marlboro.

A pile of mulch stretching two acres–500 feet wide and 50 feet high–caught fire around 8 p.m. Wednesday and burned for hours.

“It’s going to burn throughout the night,” fire officials said.

The first challenge: high winds blowing embers and sparking smaller brush fires. And with a lack of water nearby, nine tanker trucks had to haul water in from a mile away.

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“We did end up laying 3,000 feet of hose from an elementary school through the woods and down close to the site to get more water,” said Chief Benjamin Barksdale, Prince George’s County Fire Department.

Foam finally slowed the raging fire overnight and early Thursday morning.

Crews continued to douse hot spots until the flames were under control.

The accidental fire is very common on these large industrial mulch piles.

“It can spontaneously combust because it’s being compact and it’s decaying vegetation so it causes heat,” said Barksdale.

Crews are continuing to add dirt to the mulch pile just in case those flames should flare up again. They also say they’ll continue to monitor the situation and make sure it doesn’t get out of control.

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Investigators are trying to figure out what caused the fire.