Morris officials lifted the evacuation order for over 3,000 people at 4 p.m.
WATCH: Morris officials lift evacuation order, share cleaning tips for returning residents
Officials evacuated the southeast side of Morris after the fire broke out Tuesday, as toxic fumes and smoke emanated from the building, stemming from as many as 200,000 lithium batteries exploding.
Some residents who had been kept out of their homes for three days came back as soon as authorities opened up the streets.
"I'm so happy to be home," Mareli Feliciano said. She had almost no time Tuesday afternoon to pack up whatever she could as well as her three pets and get out. She has spent the time since then at a hotel, waiting to be able to return home.
Red Cross volunteers are getting ready to distribute cleaning supplies this afternoon to residents affected by the industrial fire in Morris.— American Red Cross of Illinois (@RedCrossIL) July 2, 2021
WHEN: Friday, July 2
TIME: 4 p.m. - 6 p.m.
WHERE: Morris Community High School, 1000 Union St., Morris, IL pic.twitter.com/AlUcLL3ulP
The Red Cross is handing out cleaning supplies at the high school. Health officials are urging residents to do a basic cleaning.
"It's important to wipe that dust away with a microfiber cloth, and then just use regular dish soap and water to wash anything outdoors: playsets, kids' toys," said Michelle Pruim, Grundy County Health Dept.
"Right now, the game is to let it burn itself now, the way it is, it's been Burn itself out.. right now it's controlled."
The EPA has placed air quality monitors around the town of Morris, including right at the entrance of the building. So far, they have found no evidence of harmful contaminants getting into the air.
WATCH: Drone flies over smoldering Morris battery fire
They have also been able to fly a drone inside the plant. It has thermal imaging capability to help identify any hot spots that come up.
Residents returning to their homes said they have some concerns about it, but they are trusting authorities who say it's safe at this point.
"I feel like they wouldn't release us back to the house if it wasn't safe to go back," evacuated resident Eyin Stanford said.
The fire department said they plan to monitor the situation for at least the next couple of weeks.
WATCH: Morris officials discuss progress fighting fire with cement
Official said Thursday morning they "made a lot of progress" using Portland cement mix to fight the massive industrial fire at an abandoned paper mill and that it was "in check."
Morris Fire Chief Tracey Steffes said they have used 28 tons of Portland cement to smother the burning lithium batteries, and there was no longer any active burning at the site.
Chief Steffes said that the unconventional method appears to be working, but warned it is possible the batteries could continue burning since they do not need oxygen to burn. At least three hot spots have flared up, Steffes said.
"When we smothered it with the concrete, we're not 100% sure that this thermal runaway is not continuing," Chief Steffes said. "It is probably continuing and hopefully it is going to consume what is left of the batteries underneath then it will be over. But there is a possibility that as this continues that it does break through this Portland cement."
Before using cement, firefighters tried using a dry chemical to extinguish the fire.
"We brought over 1,000 pounds of Purple-K, and we introduced that to the fire hoping we could kill it and choke it out," Steffes said. "The lithium fire laughed at the Purple-K - didn't put a dent in it."
Steffes said he has consulted with experts on how to fight the fire without making it more of an environmental problem than it already is.
SEE MORE: Morris fire: Industrial blaze prompts evacuations of 1K nearby homes
The blaze started just before 11:45 a.m. Tuesday at the old Federal Paper Board facility in the 900-block of East Benton Street.
"These batteries range in size of a cell phone to a little bigger than a car battery. As they get wet, they short out and they ignite and explode. That is the problem we are having," Steffes said. "The biggest hazard we have is the smoke and fumes as well as the gas from the fire. Highly poisonous and very deadly."
WATCH: Morris fire chief says crews working to smother blaze
Morris Mayor Chris Brown said the city was not aware of the batteries.
WATCH: Morris mayor says city unaware batteries being stored at warehouse now ablaze
"To our understanding, we were unaware of the batteries in the warehouse and only came upon it when the firemen started to do their work and push water onto the fire; they've been taking all the precautions necessary to make sure everything is safe and contained," he said.
The building's owner Jin Zheng said he was on the scene minutes after the fire started, but he was unable to get inside. He said the thick black smoke coming from the building was fueled by explosions of thousands of lithium batteries he had inside.
Zheng said he was storing supplies in the 70,000-square-foot warehouse because he was planning to open a solar power business by the end of the year.
"I have to say sorry," Zheng said.
RELATED: Morris fire: Lithium batteries a concern as blaze burns for 2nd day; evacuation order extended
Zheng said he has lost his life savings in the fire. He planned to get insurance after he opened the business. He also planned to have repairs done to the building's roof later this week, and he believes water dripping onto the batteries could have sparked the explosions and fire.
Tuesday's fire comes less than one month after the massive blaze at the Chemtool grease plant in Rockton. Special resources still in the area from that fire are now being utilized in Morris.
The Illinois EPA is monitoring air quality from several locations around town. An EPA spokesman said Friday the agency would continue working in the area. The air quality was "good" Friday, Steffes said.
Morris officials said any dust settled on items outside residents' homes should be carefully cleaned off.
Visit GrundyCo.org for more information on what to do when returning home.
The Red Cross and Salvation Army will provide supplies for those returning home at the Morris High School football field between 4 and 5 p.m. Friday.
Residents are still encouraged to call the emergency hotline at 815-941-3408 with questions.
Some residents might have lost power, Steffes said, so food safety is also important after the evacuation order is lifted.