Mobile mass spec provides new insight into pollutants released by East Palestine train derailment
Ever since a train carrying tonnes of industrial chemicals derailed in the Ohio town of East Palestine on 3 February and began leaking its contents, questions have been raised about the health effects of the disaster. In the aftermath of the incident, officials from the US Environmental Protection Agency (EPA) announced that air and water testing did not detect pick up chemicals like vinyl chloride, which were carried on the ill-fated train, at levels that were a cause for concern. Now, months later, research is shedding new light on exactly what residents and emergency workers were exposed to.
The new analysis by researchers at Carnegie Mellon University and Texas A&M University has found that some substances, including acrolein, reached levels that could be hazardous but the technology the EPA relied on wasn’t sensitive enough to pick that up. The team concludes that if ambient levels of these chemicals persisted they could pose health concerns.
East Palestine disaster
Nearby residents were evacuated following the derailment because of the risk from volatile organic compounds and particulates in the air
About 20 of the train’s 50 derailed cars contained hazardous materials – not only vinyl chloride, but also ethylene glycol, ethylhexyl acrylate, butyl acrylate and isobutylene, according to the EPA. The US National Transportation Safety Board (NTSB) confirmed that five of the derailed tank cars were carrying more than 115,000 gallons of vinyl chloride, used to make PVC, that when exposed to heat can undergo a rapid polymerisation reaction that is potentially explosive.
Some of the derailed trucks caught fire, and some spilled their loads into an adjacent ditch that feeds a stream that eventually empties into the Ohio River, the EPA said.
The situation was complicated by the fact that after the derailment some of the chemicals were burned to avoid the risk of an explosion. The subsequent release of volatile organic compounds (VOCs) triggered evacuation orders. Once residents were cleared to return to their homes, about five days later, many reported chemical exposure symptoms like headache and cough. This amplified concerns about potential short- and long-term public health impacts of the disaster.
The new Carnegie Mellon and Texas A&M research sought to independently monitor air quality and identify health risks in and around East Palestine. The team downloaded air-quality monitoring data from two EPA stations at fixed locations, and mapped patterns of airborne compounds by driving a van outfitted with a mass spectrometer around the area on 20 and 21 February. The scientists determined that the levels of nine of the 50 chemicals that were measured rose above their normal baselines, and if they had remained at those levels could have been harmful to people in the area.
Perhaps most notably, they found that acrolein levels near the derailment site a couple of weeks after the incident were as much as six times higher than the local rural background. Acrolein can severely irritate and burn the eyes, skin and mucous membranes. The train cars contained no acrolein and is most likely a byproduct of the chemicals released or burned at the scene.
However, the Carnegie Mellon and Texas A&M scientists confirmed that environmental levels of these substances decreased significantly throughout February, with vinyl chloride readings falling to levels regarded as safe. During the two days of sampling in February, the team’s equipment detected levels of benzene, toluene, xylenes and vinyl chloride that were below the minimal risk levels for exposures between 15 days and one year.
‘It’s not clear that such a short exposure is relevant to people’s health,’ Preston states. ‘But … the 90th percentile of our data is often well below the minimum risk level.’
While these findings largely corroborated the data collected by the EPA, the new mobile monitoring picked up subtleties that the agency’s monitoring stations could not. For example, acrolein and butyl acrylate were up to six times higher near the accident site during the day compared with background levels, but at night they fell below this threshold.
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