Tyngsborough police and firefighters were called to the lake just before 5 p.m. after the collision. Both boaters were able to make it to shore. Authorities did not release their names.
One of the boaters was seriously injured, and paramedics rushed them to an area hospital with serious injuries. The other did not need medical attention, Tyngsborough police said.
Massachusetts Environmental Police are investigating the cause of the crash.
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