A semitrailer truck struck the boom on a truck in Bloomington, knocking the worker from the bucket and leaving him with severe injuries, authorities said Thursday.

The incident occurred about 3:30 p.m. Wednesday along westbound Old Shakopee Road just before Hwy. 169, police said.

The semi hit the elbow of the boom, which was extended as 33-year-old Adam C. Sadd, of Minneapolis, trimmed trees, according to police. The boom truck was parked on the sidewalk, police added.

Sadd was taken by emergency responders to HCMC, where he was in critical condition Thursday.

The semi driver, David L. Jones, 59, of Belle Plaine, was not hurt, and he showed "no indications of impairment," a police statement said. "The driver cooperated with officers at the scene of the crash."