NEW YORK — Authorities are looking into whether sun glare was a factor in an accident in which a ferry departing a New York City pier slammed into a group of kayakers, critically injuring one.

Police say 10 people in eight kayaks were paddling down the Hudson River on Tuesday evening on a sunset excursion when they were struck by a NY Waterway ferry.

Five people were hurt. An employee of the Manhattan Kayak Co. suffered the most serious injury. His arm was partially severed.

Authorities don’t know what caused the crash but say they’re investigating whether sun glare played a role.

A spokesman for NY Waterway says it’s cooperating with police and the Coast Guard.

A message left with the Manhattan Kayak Co. hasn’t been returned.

This story has been corrected to show the accident was Tuesday, not Thursday.