For days, authorities have been telling residents of the area around East Palestine, Ohio, that it is safe to return home after a 150-car train carrying hazardous chemicals derailed Feb. 3.

The Ohio Department of Natural Resources said the chemical spill resulting from the derailment had killed an estimated 3,500 small fish across 7½ miles of streams as of Wednesday.

And one resident of North Lima, more than 10 miles from East Palestine, told WKBN-TV of Youngstown that her five hens and rooster died suddenly Tuesday. The day before, rail operator Norfolk Southern had burned train cars carrying vinyl chloride — a flammable gas — to prevent an explosion.

For some people who live near the derailment site, the reports continue to spur fear that they and their animals might be exposed to chemicals through the air, water and soil.

“Don’t tell me it’s safe. Something is going on if the fish are floating in the creek,” Cathey Reese, who lives in Negley, Ohio, told NBC affiliate WPXI of Pittsburgh last week. Reese said she saw dead fish in a stream that flows through her backyard.

Jenna Giannios, 39, a wedding photographer in nearby Boardman, said she has had a persistent cough for the past week and a half. She has been drinking bottled water, and she is uncomfortable bathing in water from the bathroom spigot, she said.

“They only evacuated only 1 mile from that space, and that’s just insane to me,” she said, coughing throughout the conversation. “I’m concerned with the long-term heath impact. It’s just a mess.”

After the controlled burn, the Environmental Protection Agency warned area residents of possible lingering odors but noted that the byproducts of vinyl chloride can emit smells at levels lower than what is considered hazardous.

Ohio officials said Wednesday that residents could return home after air quality samples “showed readings at points below safety screening levels for contaminants of concern.”

The EPA, which is overseeing the air quality testing, said, “Air monitoring since the fire went out has not detected any levels of concern in the community that can be attributed to the incident at this time.”

However, the EPA said Friday in a letter to Norfolk Southern that chemicals carried on the train “continue to be released to the air, surface soils, and surface waters.”

The EPA said that as of Saturday evening, it had screened the indoor air in 210 homes and hadn’t detected vinyl chloride. Another 218 homes had yet to be screened as of Sunday, it said.

The EPA classifies vinyl chloride as a carcinogen; routine exposure could increase one’s risk of liver damage or liver cancer. Short-term exposure to high concentrations can cause drowsiness, loss of coordination, disorientation, nausea, headache or burning or tingling, according to the Centers for Disease Control and Prevention.

East Palestine has scheduled an emergency council meeting for Wednesday to respond to constituents’ concerns.

Andrew Whelton, a professor of environmental and ecological engineering at Purdue University, said it’s possible the burn created additional compounds the EPA might not be testing for.

“When they combusted the materials, they created other chemicals. The question is what did they create?” he said.

Whelton added that some of the other chemicals the train carried could also cause headaches, nausea, vomiting or skin irritation.

In Darlington, Pennsylvania, 4 miles from the accident, managers of the Kindred Spirits Rescue Ranch evacuated 77 of their biggest animals, including a yak and a zebu, for two days.

“We could see the plume come up and over us,” said the ranch’s founder, Lisa Marie Sopko. “Our eyes were burning, and my face could feel it.”

Sopko said she’s concerned about the conditions. The ranch’s water comes from its own two wells, but until experts can test them, Sopko said, her team is using one well with a more sophisticated filtration system.

The Ohio Department of Agriculture said the risk to livestock remains low.

“ODA has not received any official reports regarding the wellness of animals related to the incident,” it said in a statement.

Still, the Ohio Farm Bureau Federation is urging members to get the water from their local wells tested as soon as possible.

“The biggest concern is the water table at this point, to see what kind of exposure there has been to these chemicals,” said the bureau’s organizing director, Nick Kennedy.

“There’s some level of frustration out there” among farmers, Kennedy added. “They just want answers. Their livelihoods might be at stake here.”

Laura Fauss, the public information officer for the Columbiana County Health District, said the department began groundwater sampling last week in partnership with the state Health Department, the state EPA and contractors for Norfolk Southern.

The results haven’t come back yet, Fauss said, and she didn’t know when to expect them.

She added that her department has received no reports of residents’ experiencing abnormal symptoms.

But Giannios said she and other residents haven’t gotten all their questions answered, so in the meantime, she has started a Facebook page where people can keep in touch about their concerns.