The Centers for Disease Control and Prevention confirmed that seven members of a 15-person team became sick after assessing the potential health impacts of Februarys train derailment in East Palestine, Ohio.
The news was originally reported by CNN.
The CDC said that members of the Agency for Toxic Substances and Disease Registry started became ill on March 6 with symptoms including sore throat, headache, coughing and nausea. A CDC spokesperson said the symptoms were consistent with what residents have been reporting on Assessment of Chemical Exposure surveys.
A CDC spokesperson said staff members symptoms resolved by the afternoon and they were able to return to work by the next day.
Impacted team members have not reported ongoing health effects, the CDC said.
SEE MORE: Justice Department sues Norfolk Southern over toxic train derailment
The team has been in East Palestine and surrounding communities since February collecting health surveys. As of March 30, 704 resident surveys have been completed. There have also been 318 surveys of responders.
The CDC said that survey collection ended on March 31 and staff will analyze the data and provide it to state health officials in Ohio and Pennsylvania.
Although officials have said the air is safe, there remain lingering concerns over the long-term impacts after vinyl chloride and other chemicals were released into the atmosphere.
According to the Environmental Protection Agency, vinyl chloride is highly flammable and is mostly used to make polyvinyl chloride (PVC) plastic and vinyl products. Short-term exposure to the chemical can cause dizziness, drowsiness, and headaches. Long-term exposure can result in liver damage and cancer concerns, the EPA said.