SOUTH PORTLAND (AP) – The Coast Guard is investigating the cause of a 670-gallon asphalt spill at the Sprague Energy terminal along the Fore River in South Portland.

Officials say the spill occurred Tuesday evening as the vessel Asphalt Seminole was transferring the hot asphalt to the terminal.

Once in contact with the cold water, the asphalt solidified and formed a pancake-like material within the containment boom that was in place around the veseel during the off-loading.

Sprague contracted with a pollution services firm to clean up the spill.