Hudson, MA – A carbon monoxide incident at a shopping plaza in Hudson sent three people to the hospital on Tuesday, Deputy Fire Chief Mike Parker told Boston 25 News.

Emergency crews were called to The Paper Store on Technology Drive around 11:15 a.m. People reported smelling gas and not feeling well.

Parker said carbon monoxide was detected in multiple buildings. The Paper Store is part of a strip mall that’s also home to Sperry’s Liquors, Eye Care Center, The UPS Store, Hair Cuttery and Checkerboards Pizza Restaurant and Bar.

The buildings were evacuated until around 1 p.m. when carbon monoxide was no longer detected.

Three people were taken to UMass Memorial – Marlborough Hospital for treatment. Their conditions are unknown.