For more than a month, residents of Mayflower, Ark. have been told not to worry about lingering fumes from a March 29 oil spill that shut down a neighborhood and forced the evacuation of 22 homes.

“Overall, air emissions in the community continue to be below levels likely to cause health effects for the general population,” Arkansas regulators wrote on a state-operated website that tracks Mayflower’s air monitoring data.

Despite these reassurances, residents have suffered headaches, nausea and vomiting—classic symptoms of short-term exposure to the chemicals found in crude oil.

“Figuring out how to protect people after a disaster like this is very hard,” said Aaron Bernstein, a public health expert and associate director of Harvard’s Center for Health and the Global Environment. “People living near the spill early on could definitely have gotten sick” from the concentrations present in the air.

Much of the attention is focused on airborne levels of benzene, a known carcinogen that is toxic at very low doses. But crude oil also contains hundreds of other chemicals, and for some of these compounds, little is known about their effects on human health.

Given the gaps in scientific research, public health experts say it’s hard to know what levels of exposure are safe.

Guidelines provided by the Arkansas Department of Health are meant to protect the public from long-term impacts—benzene, for example, is known to cause cancer after prolonged exposure, and many of the other chemicals found in crude oil are also known or suspected carcinogens. But the guidelines don’t cover short-term impacts, and experts interviewed by InsideClimate News worry that not enough is being done to address the short-term problems caused by exposure to the 210,000-gallon oil spill.

The people with acute symptoms are going through something that is “real and really debilitating,” said Wilma Subra, an environmental consultant who has spent decades working with communities hit by chemical accidents. Subra is the recipient of a MacArthur “genius” grant and works extensively with people impacted by the BP Gulf spill.

Subra said she’s concerned that only 22 families were evacuated. “They focused on the 22 homes … but all around there’s residential homes, churches, schools, and those people were just ignored.”

Three days after the spill, indoor air monitoring showed that the air inside the elementary school—which lies about half a mile from the rupture site—was safe to breathe. But eight students were sent home after falling sick from headaches and vomiting.

Shelia Harrell, who lives two blocks from where the crude oil bubbled out of the ground, said that although residents on the other side of the subdivision were evacuated, she received no guidance about whether she should leave her home as a precaution. So Harrell and her husband stayed put, enduring several nights of burning, acrid odors. Now she’s worried about what exactly she was exposed to during that time.

Diane Wilson lives on the other side of town, outside the mandatory evacuation zone but next to a lake contaminated by the oil. One of her neighbors broke out in hives. Another left home after throwing up from the fumes. The smell was so bad that Wilson and her husband couldn’t finish renovations they’d started on their garage. She said it was at least a week before the fumes started to fade.

Dr. William Mason, chief of emergency response at the Arkansas Department of Health, said the acute symptoms should be temporary, and that residents could have left their homes if they were concerned. ExxonMobil, the company responsible for the ruptured pipeline, has offered to pay hotel bills for residents outside the mandatory evacuation zone, as well as for the official evacuees.

“When you have a population that’s been exposed to noxious fumes of this type…there’s going to be a response,” Mason said. “It can be dizziness, nausea, headaches or vomiting…Certainly if they were having complaints, the option for them to leave is their personal choice.”

Some members of the public will be more sensitive to the fumes than others, said Elena Craft, a toxicologist at the Environmental Defense Fund, an advocacy group. “Obviously children and older folks are way more susceptible than adults … [and] the stress of the situation” can exacerbate symptoms. “There’s a psychological component as well that needs to be factored in.”

The U.S. Environmental Protection Agency and Exxon are still monitoring the air in Mayflower, and the Arkansas Department of Health reviews the data before posting the information on the Arkansas Department of Environmental Quality website.

But the government’s attempt at transparency has fallen short. The air quality database is complex and incomplete—even health professionals can’t fully analyze it without requesting additional information. For instance, the EPA took air quality samples at several locations around Mayflower, but the code needed to match the data points with the places where the samples were taken isn’t posted online.

Few Answers Available

Those who are sick in Mayflower have few places to turn for answers: no central health clinic has been set up for affected residents, and most family doctors have little experience treating chemical exposure.

“Most medical schools have little to no faculty with this kind of expertise,” Bernstein said, and many students finish medical school with no more than a few hours of instruction in environmental health.

Subra said that after the BP oil spill, residents along the Gulf Coast were also left without answers. “We have struggled for the last three years to get them appropriate treatment from doctors who understand toxic exposure.”

Subra has tried and failed to obtain federal funding to bring specialists to coastal areas so they can train local doctors. These specialists tend to work in large cities, charge a lot of money, and are unavailable to most residents, she said.

Her advice to the people of Mayflower is to reduce their exposure as much as possible and to stay away from areas where the cleanup continues.