SWANTON — A Thursday afternoon chemical spill at the Tractor Supply store on Route 207 here sent five people to the Northwestern Medical Center and has police investigating what they consider “suspicious circumstances.”

Numerous fire departments, ambulances, American Red Cross, Vermont State Police and the Vermont State HAZMAT Response Team were on scene yesterday for several hours investigating and cleaning up the spill.

Emergency responders initially received a call just before 2 p.m. yesterday regarding four Tractor Supply employees suffering from some sort of chemical inhalation. The store was evacuated and those employees were immediately sent to NMC. One more employee went there soon after.

“We know that there was what appears to be some type of chemical exposure in the store that affected five employees,” said Vermont State Police St. Albans Barracks Lt. John Flannigan. All were treated and released later in the day for what appeared to be inhalation exposure.

Flannigan was unsure on Thursday how many customers were in the store at the time of exposure.

The type of chemical that was released in the store has not been indicated by Vermont State Police, and a cause for the spill remains under investigation. As of now, police believe that “suspicious circumstances” were involved.

Police originally released a security camera photo of two young men who were in the store just prior to the spill, but upon hearing their images had been distributed by the news media, the two young men returned to be identified and interviewed. Police made no accusations against them.

Police are looking for tips from anyone who may have been in the store between 1 and 1:48 p.m. Thursday. If you have any information, please contact the Vermont State Police at 802-524-5993 or submit an anonymous tip to www.vtips.info.