PORTLAND — An underground power line failure probably caused a small explosion that lifted a utility manhole cover on Commercial Street this afternoon, according to a Central Maine Power Co. spokesman.

The explosion near 468 Commercial St. was reported to police shortly after 4 p.m., said Nicole Clegg, spokesman for the city of Portland.

Portland firefighters responded and found no fire and no injuries in the area, Clegg said.

CMP workers arrived later to fix the power line failure, which caused no customer outages, the CMP spokesman said.