Originally Published: 11 APR 23 22:38 ET

Updated: 13 APR 23 00:07 ET

By Omar Jimenez, Bonney Kapp, Sara Smart, Brenda Goodman, Michelle Krupa and Holly Yan, CNN

(CNN) -- The raging fire shooting toxic smoke from an eastern Indiana recycling plant has forced thousands of people to evacuate and countless more to wonder what the impacts might be to their health and environment.

Plastics were among the items that started burning Tuesday at the Richmond plant. And the thick, black column of smoke that rose from the site is "definitely toxic," Indiana State Fire Marshal Steve Jones said.

"There is a host of different chemicals that plastics give off when they're on fire, and it's concerning," Jones said Tuesday evening. He said the fire will likely burn for days.

The US Environmental Protection Agency said Wednesday night it was evaluating the area, including school grounds, for potential fire debris that may contain asbestos. Asbestos is a naturally occurring, but very toxic, substance that was once widely used for insulation.

When inhaled or ingested, asbestos fibers can become trapped in the body, and may eventually cause genetic damage to the body's cells. Exposure may also cause mesothelioma, a rare and aggressive form of cancer.

While the cause of the inferno is not yet known, city officials "were aware that what was operating here was a fire hazard," Richmond Mayor Dave Snow said Wednesday. "This was a fear for us."

No major injuries were reported, but about 2,000 of the city's 35,000 residents near the Ohio border were ordered to evacuate.

The evacuation zone covered residents within a half-mile of the fire, but authorities could change it if wind direction shifts, Jones said.

Residents downwind of the evacuation zone -- to the east and northeast -- were encouraged to shelter in place and bring pets indoors.

'The biggest risk is the unknown chemicals'

Air quality tests by the US Environmental Protection Agency had not found toxic chemicals such as styrene or benzene as of mid-Wednesday morning.

Tests will continue as the smoke dissipates, emergency response on-scene coordinator Jason Sewell said. The EPA collected measurements overnight Tuesday into Wednesday, monitoring particulate matter and looking for toxic chemicals.

But "the biggest risk is the unknown chemicals that are formed as the compounds burn," said Richard Peltier, associate professor of environmental health sciences at the University of Massachusetts-Amherst.

"We know that it is very common that a large range of chemicals are formed whenever plastic materials are burned, including styrene, benzene, and a wide number of polyaromatic hydrocarbons -- all of these are strong carcinogens, and it's important for people to avoid exposures," Peltier said.

Potential short-term health risks could include symptoms such as dizziness, nausea, coughing, headache and fatigue, Peltier said. "Asthma is regularly triggered by these types of complicated exposures so if you have asthma, it's really important to be extra careful," he said.

Longer-term problems could include an increased risk of cancer if someone is exposed to a high concentration of toxins for a prolonged period of time.

So, "just because you have a short-term exposure doesn't necessarily mean you will get cancer," Peltier said. "Your risk increases with duration and concentration."

For the first responders in Richmond, "it's important that they wear full-face respirators, and (possibly) with tanked air," Peltier said. "Their exposures will be to a profound mixture of particles (which can be filtered) and gases (which cannot), and they need to take extraordinary measures to remain safe."

'I didn't have shoes on' and fled

The billowing black smoke stirred memories of the recent toxic train wreck in East Palestine, Ohio. After a Norfolk Southern train carrying hazardous materials derailed, a days-long inferno ensued. High levels of some chemicals from that disaster could pose long-term risks, researchers have said.

Richmond resident Brenda Jerrell "didn't hesitate" to leave her home near the burning recycling plant. "The smell had already been bad," she told CNN.

"I didn't have shoes on; I had socks on," she said. "I left my purse, my shoes -- I left a lot of things, personal things ... and just got in the car and drove away."

Covering her mouth and nose with a mask, Jerrell was "still worried because they're telling us they don't know what was burning and that, you know, irritation may occur."

For now, the main health concern is smoke, Wayne County Health Department Executive Director Christine Stinson said Wednesday.

"These are very fine particles -- and if they're breathed in can cause all kinds of respiratory problems: burning of the eyes, tightening of the chest, it could aggravate asthma, cause bronchitis and all kinds of things," she said.

The EPA will "absolutely" be involved in monitoring air quality in Richmond, its administrator told CNN on Wednesday.

"We're going to keep the emergency response group on the ground, up-to-speed on what those results are," Michael Regan said.

"We've been on site since the beginning, and we're going to stay there until we can assure that this community is not seeing any threats from the air quality implications here."

Toxic pollutants could pose risks, experts say

N95 masks -- the kind widely used during the Covid-19 pandemic -- are most protective against particulate matter in the area, but if people are seeing or smelling smoke or experiencing symptoms, they should leave, Stinson said.

Planet-warming pollution also surely is being emitted from the fire, said former Regional EPA Administrator Judith Enck, now president of Beyond Plastics, which aims to end plastic pollution.

"But the bigger issue is that when plastics are burned, dioxin is often formed," she told CNN. The EPA says dioxins are highly toxic pollutants that can cause cancer, and reproductive and developmental problems. They also take a long time to break down.

Dioxin tests must be done by state officials, Enck said. "Even small amounts can cause significant health damage." Phthalates, bisphenols and microplastics are also released when plastics are burned, she added.

"Plastics burn hot and fast," Enck said. "Lots of chemicals can be released, so (plastic) should not be stockpiled."

Stockpiling, however, is a common problem at plastics recycling facilities since there are so few reliable domestic markets, she said.

The 175,000-square-foot facility burning in Richmond is "completely full from floor to ceiling and from wall to wall," city Fire Chief Tim Brown said Tuesday.

Officials warn residents: Don't touch debris in your yard

Melted plastics and roofing materials have been identified in pictures from residents.

But those who find remnants from the fire in their yards are asked to "not disturb or touch the debris" because "it is unknown what chemicals may or may not be in the debris," Wayne County Emergency Management Agency officials said.

EPA officials plan to sample those materials and send them off for analysis, Sewell said.

"Based on the age of the building, it's possible there could be asbestos-containing materials in some degree that would have left the site," Sewell said Wednesday, referring to naturally occurring, toxic minerals that were long used in items such as home insulation and hair dryers.

"We would ask that people certainly do not mow the debris," Sewell said. "If you're finding debris in your yard, leave it be until we know more information. Certainly, don't mow it up."

'The largest fire I've seen in my career'

Firefighters responded to the recycling facility Tuesday to find a semitrailer behind one of the plant's buildings engulfed in flames, Brown said.

The trailer was loaded with an "unknown type of plastics," and the fire spread to other piles of plastics around the trailer and eventually to the building, Brown said.

Firefighters had trouble getting access to the facility, with piles of plastic blocking access roads, Brown said. "It creates quite a challenge because we only have access to one side of the building," he added.

"Once the fire got out of control, it darkened down on us, (and) we backed out real quick and then went into defensive mode," Brown said.

The flames spread to several buildings at the site, but crews managed to stop the fire's spread before it could jump into residential areas, Brown said.

"It's probably the largest fire I've seen in my career," Brown said.

One firefighter was released from a hospital after falling and hurting his ankle, Brown said, and no other injuries were reported. Everyone who was said to be working at the building when crews responded to the scene has been accounted for, he said.