The Department of Health and Human Services is offering a free blood test to people who may have drunk contaminated water at the Pease Tradeport in Portsmouth last year.

Perfluorochemicals, or PFCs, are used in products that resist heat – like Teflon, and the foam once used for fighting fires at Pease Airforce Base. PFCs were found in a well at the Pease Tradeport in May 2014.

State officials have shut-down one of three drinking water wells that serve the Pease Tradeport. The well was contaminated with an unregulated chemical found in foams used by firefighters.

Perflourooctane Sulfonic Acid, or PFOS, was found in the well which serves the 250 businesses and 8,300 employees of the Pease Tradeport. It was detected in levels that exceed a “provisional health advisory” level set by the EPA.