“It’s Worrisome to Not Have Data.” An Expert Questions Whether Air Is Safe After Train Derailment

Questions of air safety remain in East Palestine, Ohio, following the Feb. 3 train derailment that sent industrial chemicals, including the carcinogen vinyl chloride, into the atmosphere. Ohio Governor Mike DeWine cleared residents who had evacuated to return home this week, stating that repeated air testing conducted by the U.S. Environmental Protection Agency (EPA) was no longer revealing dangerous levels of any contaminants.

But the agency has yet to publicly release any quantifiable data on the area’s pollution. The result is confusion about exactly what may or may not be lingering in the air, and what that means for the health of people in the area.

Peter DeCarlo, an associate environmental health and engineering professor who studies atmospheric air pollution at Johns Hopkins University, weighed in on the EPA’s testing methods and what questions residents should be asking. (This interview has been edited and condensed for clarity.)

TIME: Can you tell me a little bit about what you do, and how it relates to the crisis in East Palestine?

Peter DeCarlo: I’m an atmospheric chemist, and my focus in my research is the measurement of trace gasses and particles in the atmosphere—understanding where they came from. The research that we do is all about going outside and taking measurements and really trying to understand what’s in the air that we breathe.

In East Palestine, that would mean trying to figure out what pollutants people have been exposed to from the initial crash and during the fire, and trying to understand if the measurements are being done in a way such that when people are told it’s safe to go home, that it really truly is safe to go home. If we don’t have the measurements and really know what chemical species are present, it’s really hard to understand what potential risks they are facing now and in the future.

From what you’ve heard, how have those measurements gone so far in Ohio?

I think there is an overreliance on handheld monitors that are really not designed for ambient air monitoring. They have a use early on in an incident, when first responders are going to the scene—they’re good in a quick assessment to know that people who are there as first responders are in a place that’s not unsafe. That they’re now relying on them for ambient air monitoring and screening of homes is an inappropriate use of the technology, in my opinion.

What makes them such unreliable options?

There are a couple of reasons. First, they don’t have chemical specificity. They don’t actually measure the chemicals that we need to know about. Instead, they measure all of them as a single class—we would call it VOCs, or volatile organic compounds. But that includes things like perfumes; that includes a whole host of things that are not going to have the same toxicity as some of the chemicals that we’re worried about. There are chemicals that are classified as VOCs that are not harmful, so if you’re not specifying which chemicals are being measured, you’re losing out on understanding what people are being exposed to precisely.

Second, these instruments are not very sensitive. When you’re making these handheld measurements in an industrial area, or right at the onset of an accident, you’re trying to understand safety for first responders, who are generally a much more healthy population. They have a higher tolerance than people who are considered vulnerable, which includes kids, the elderly population, and people with preexisting health conditions.

These tools have their use. They’re just not for telling people it’s safe to go home.

How should officials be testing the air instead?

The EPA is also doing what they call air sampling, which is a pretty old technology. You basically take a stainless steel container that has no air in it, and you open it up, and it sucks air in—letting you get a sample of air at a particular place and time. You then take that back to the laboratory and use much higher-sensitivity instruments to characterize what chemicals specifically are in that air, and at what concentration. That type of measurement does provide the information we need—it gives us chemical specificity.

But they’re not using them in peoples’ houses. With that type of information in someone’s home, for example, I would have more confidence that the air was clean.

What’s stopping them from doing it that way?

An important thing that hasn’t been discussed at all is underinvestment in our environmental agencies. At state and federal levels, you can look at the number of personnel employed over time, and it’s gone down considerably. Funding levels being down means they don’t necessarily have the best people and the best equipment available to respond to these types of emergencies.

This is another question that we have to ask: are we investing enough, so that when these types of things happen, we can have the best response? This is not the first, and it’s probably not going to be the last accident like it.

Some of the contents of the cars caught on fire as the transit company was releasing them from the cars. How does all that smoke and fire affect what’s in the air?

The big plume of smoke that I think pretty much everyone has seen by now—that’s a bunch of particulate matter. It’s not just gasses anymore.

Anytime you burn something, it chemically changes. It’s no longer, you know, vinyl chloride when you light it on fire—it’s combustion byproducts of vinyl chloride, many of which are potentially more toxic. We’ve even seen discussions of phosgene [one of the many gasses and other byproducts released when vinyl chloride is burned], which is a World War I chemical warfare agent. These are chemicals that are produced from combustion, and there are probably thousands of different ones, because it’s a very uncontrolled process.

When you make that kind of particulate matter, the material can deposit on surfaces in a home or downwind. The EPA has technology to do surface wipes, including taking those wipes back to a lab and analyzing what chemicals might be on there.

If residents—particularly parents, pet owners, and those with elderly relatives—are concerned, what should they do?

We don’t have the publicly available data at this point to really understand what risks are there, even though we know that they exist. It’s worrisome to not have data, especially in people’s homes.

Pets, for instance, have different routes of exposure. I grew up with dogs—they drink water from streams, so that’s one route of exposure that I hope people are being careful of. Kids shouldn’t be playing in creeks. For young kids, they crawl around on the ground, things go in their mouths—there are just way more ways that kids can be exposed. And that’s worrisome, because early life exposures can be problematic. It’s certainly something to avoid. Water and soil tend to have a longer memory than air.

What are we looking at in the long term for East Palestine?

I can’t say without appropriate measurement data. There’s nothing publicly available that gives me an indication of if there are continuing emissions and how long those might be going for. Soil and water are avenues that take a little bit longer to be remediated, and it’s not clear what the plan is for those. But certainly, I think those chemicals are going to be there for a while.