causing severe injuries to two of the hikers

[sunsunmoon]

Bear attacks seven teens in Alaska - Seven News Queensland

A grizzly bear sow with a cub attacked a group of US teenagers on a month-long survival-skills course causing severe injuries to two of the hikers.

Is this sentence OK without a comma before the "causing"?

[bhaisahab]

Bear attacks seven teens in Alaska - Seven News Queensland

A grizzly bear sow with a cub attacked a group of US teenagers on a month-long survival-skills course causing severe injuries to two of the hikers.

Is this sentence OK without a comma before the "causing"?

No, it needs a comma.