Earlier this month, seven CDC investigators studying potential health risks associated with the train derailment in East Palestine, Ohio, briefly fell ill, experiencing symptoms including headache, sore throat, coughing and nausea, according to a March 31 report from CNN.
The symptoms are in line with what residents in the area have reported after a Norfolk Southern train carrying six hazardous industrial chemicals derailed in the community Feb. 3. One of the chemicals involved in the incident was vinyl chloride, a carcinogen.
In late February, the CDC sent a team of 15 epidemiologists and environmental health scientists to conduct door-to-door surveys in the area near the derailment. Team members often worked 18-hour days, asking residents detailed questions about where they were in the days after the spill and what symptoms they may have experienced, sources familiar with the matter told CNN.
Half of the investigators briefly fell ill in early March and were able to resume their work a day later. It's unclear whether their symptoms were caused by chemical exposure or something else, such as fatigue, though team members were suspicious since they became ill at the same time with the same symptoms, a source told the news outlet.
"Symptoms resolved for most team members later the same afternoon, and everyone resumed work on survey data collection within 24 hours," a CDC spokesperson told CNN. "Impacted team members have not reported ongoing health effects."
Some medical professionals in the area believe the train derailment is behind a swath of respiratory issues and other ailments residents are experiencing. In late February, a nurse practitioner at an urgent care clinic near East Palestine told NBC she has been seeing between five and 10 people per day displaying symptoms consistent with chemical exposure.