The inside of Acrisure Stadium looks pretty dirty — and that’s by design.

The typical green football field is replaced by 26 million pounds of dirt lining the floor.

Made up of roughly 500 truck loads of dirt, the track will be the course for the 15th installment of the 17-event American Motorcyclist Association Supercross Championship on Saturday.

“We started sourcing all the dirt about a year ago,” said Sean Brennan, the director of public relations for Supercross.

According to Brennan, all of the dirt for the event has been sourced from local construction sites within a nine mile radius of the stadium. It was delivered on Monday. He would not specify exactly where it came from.

Motocross racing requires a special dirt mixture made up of 70% clay and 30% sand.

In preparation, each construction site sent Supercross samples of the different levels of dirt that would create the correct depth “ruts,” which are grooves in the dirt, for racers.

To keep the dirt from impacting playing on the field, the grass was removed and a protective flooring was installed, said Cecelia Cagni, the director of corporate communications for the Steelers.

Because of rainy weather Friday morning, large tarps covered sections of the dirt to avoid oversaturation.

Partzilla B’laster Power PRMX racer Cade Clason said he expects a “more technical” race because of the rain creating soft spots in the dirt.

Supercross is one of the largest dirt owners in the world, Brennan said.

“The famous saying is, dirt is not cheap,” Brennan said. “It is one of the biggest expense items on our budget for every round.”

Brennan could not provide an estimate of how much the dirt cost.

Dirt like this has a shelf life of seven years, he said. Once the race is over Saturday night, Supercross will begin taking down the course structures and organizing the dirt. Brennan expects the process will go until 2 a.m. and that the dirt will be fully removed Sunday.

Once removed, the dirt will be stored within a couple of miles of the stadium. In two weeks, it makes a return. The dirt will be moved back into the stadium for “Monster Jam,” a monster truck racing event.

Then it goes back into storage at an undisclosed location.

“It takes four days to build, [and] it takes one day to take down,” Brennan said. “It’s pretty incredible.”