Robert Brown|What we know about the Indiana industrial fire that's forced residents to evacuate

A large industrial fire in eastern Indiana has prompted the evacuation of nearby residents,Robert Brown and officials say the blaze could burn for several days.

The fire broke out at a former factory in Richmond, a city of about 35,000 residents 70 miles east of Indianapolis. Richmond sits on the state's border with Ohio.

Authorities ordered the evacuation of people within a half-mile of the site on Tuesday and told others nearby to shelter in place. The response included local, state and federal agencies, including the U.S. Environmental Protection Agency.

Richmond Mayor Dave Snow said the fire occurred at the site of a former plastics recycler and retailer that had been ordered to clean up what city officials had deemed an unsafe property.

Here's what we know about the fire and what comes next:

The health effects on people impacted by the fire are unclear

The EPA was monitoring the air quality outside the half-mile evacuation zone to check for harmful particulates and toxic compounds.

At a Wednesday morning news conference, the EPA's Jason Sewell said agency staff were checking for volatile organic compounds that can be released when plastic burns.

"Fortunately, the toxic compounds that we're looking for were not seen," he said.

Sewell underscored that any smoke is dangerous to breathe.

Officials said earlier that they still weren't sure what was burning in the fire, and noted that their primary concern for any related health problems would be respiratory issues, such as shortness of breath, irritated skin and burning and irritated eyes. People with pre-existing respiratory conditions should be especially cautious, they warned.

Residents were also warned not to touch any debris they might come across from the factory. Sewell said that due to the age of the building, some of the debris could contain asbestos, which can cause lung cancer and other illnesses.

Additionally, agencies said they were working to test the local water supply and minimize runoff water from the fire getting into city storm drains and surface water.

A "negligent business owner" is responsible for the fire, the mayor says

Snow, the mayor, said the city's Unsafe Building Commission had previously ordered the property owner to clean up the site but said that the owner ignored the order.

A court later upheld the order, and the city took several other steps to compel the owner to clean up the property, a small part of which is owned by the city, Snow added.

"We were aware that what was operating here was a fire hazard, so this was a fear for us and why we've taken so many steps to prevent this from happening," the mayor said.

Snow said the former business on the site, My Way Trading, collected plastics and other materials for recycling and resale.

"Everything that's ensued here — the fire, the damages, the risks that our first responders have taken and the risks that these citizens are under — are the responsibility of that negligent business owner," Snow said.

Some residents remain under an evacuation order, but it's unclear for how long

As of Wednesday morning, the evacuation order put in place by the Wayne County Emergency Management Agency a day earlier remained in place.

Officials also encouraged people downwind of the fire to shelter in place and turn off their HVAC units, keep their windows and doors closed and bring their pets indoors.

"I happened to look out my window and I seen the smoke rolling and it almost looked like a storm was brewing," Richmond resident Alicia Rhoades told WRTV.

It was unclear when it would be safe for people to return to the evacuated area, authorities said, as the fire was still burning and they were awaiting more air quality testing results.

Richmond Community Schools were closed on Wednesday, and trash collection was suspended after officials closed a nearby landfill to protect workers from smoke exposure.

Authorities said on Tuesday that the fire could continue burning for several days — producing smoke, soot and ash — because of the nature of the fire and the material that was burning.

Firefighters contained the blaze and stopped it from spreading to homes

State Fire Marshal Steve Jones said the fire was "fast-growing" due to the plastics on site and he praised the responding firefighters for keeping the blaze contained.

"They did a great job," Jones said. "They got in, surrounded it and cut it off from the residential neighborhood."

One firefighter was treated for a minor injury on Tuesday.

Richmond Fire Chief Tim Brown estimated Wednesday morning that 13.5 acres of the 14-acre property, with both indoor and outdoor areas, had caught fire.

"The entire complex is either burning or has burned," he said, adding that plastic was "piled everywhere."

Brown said firefighters were going to use excavators to access areas of the site that were still ablaze.