Lifestar was called to One Research Parkway in Meriden after a wall collapsed.
A retaining wall fell on a construction worker around 3 p.m. at a worksite that is the future home of a car wash.
Concrete from the wall pinned the man against a dump truck, according to fire officials. Emergency crews freed the man, but he went into cardiac arrest, fire officials said.
The work crew was digging along the retaining wall to install new curbing when the wall became unstable and collapsed, according to police.
Lifestar helicopter transported the man to the hospital. His name and condition have not been released.
Meriden police and the Occupational Safety and Health Administration are investigating the accident.