LA SALLE, Ill. — Clean-up after a massive fire at a chemical plant in La Salle has moved to a long-term phase, the city announced Friday.

Officials are still unsure what caused the fire and are testing the air and water quality to narrow down the source.

Residents say they heard several loud explosions followed by witnessing massive plumes of black smoke from the carcass chemical plant. Police said employees were able to get out but one firefighter suffered minor injuries.

A spokesperson said the fire started in the warehouse but did not share what started it.

The chemical plant itself produces potassium that is used to treat drinking and wastewater. The fire released a green-like substance that fell on people’s homes, yards and cars.

“I mean the particles are kind of just everywhere, anything that was outside,” resident Ruth García said. “It’s in the grass. You can see it’s dark in some areas, black in some areas, it’s green. Some people reported seeing purple.”

García said anything that was outside was exposed. She’s concerned about the well-being of her animals and herself.

“I did spray off the driveway and the door handles and everything like that, but as far as cleaning anything else, I just don’t feel comfortable coming into contact with it,” García said.

Police warned the community not to touch it and that it can be washed off with a mixture of equal parts, water, peroxide and vinegar but residents are concerned of long-lasting damage.

“For them to say that they would let their dog in their backyard and eat the grass where that stuff fell on, I find that really appalling,” Jamie Hicks, a nearby resident said.

For countless hours, Juan Torres has devoted time to cleaning the residue off his home, yard and cars.

He has been mostly successful but his truck got oxidized and it was not a pleasant surprise.

“We pay for it, I don’t know how much it’s going to cost to paint the truck,” Torres said.

The U.S. Environmental Protection Agency has been on the ground checking the air and water quality to determine if there are any concerning pollutants. As of Friday, the U.S. EPA said no levels of concern have been noted.

Carus will continue to monitor the air during the long-term clean-up.

Officials acknowledge the concerns residents have about their environmental and health conditions.

They said they will be transparent once they have all the details, but residents are still unsure on how they’re supposed to proceed.

Officials provided a small update Thursday afternoon which included a hotline setup by Carus to take questions: (815) 224-6662.

Watch the full press conference in the video below.