Ed. note: Post updated with fact it was steam, not smoke from a fire.

The Cambridge Fire Department reports what appeared to be smoke was actually just steam from a manhole at Land Boulevard and the Monsignor O'Brien Highway shortly after 7 p.m.

Still, police shut the roads down by the Museum of Science as a precaution until firefighters could confirm that.

Matthew Gregoire surveys the scene at North Marginal and Cooper streets.

KMV shows us one of the three manholes on Lake Street that burst into flames shortly before 8 a.m.

UPDATE: Greater Boston Radio reports inspectors cleared the three manholes and ordered the power back on - and three manholes one street over promptly blew up.

Firefighters and utility crews are at Tremont and Parrker streets, where a manhole burst into flames around 8 p.m. Tremont was shut in both directions.

Shortly before 11 a.m., in the area of Cambridge and New Sudbury streets. WCVB reports several manhole explosions.

Ted Folkman reports:

Just saw a manhole cover explode right outside the JFK building, and loud boom. Smoke billowing out!

Video from WHDH.

Firefighters are at Summer and High streets for a manhole that belched fire and smoke.

Alex Carlson reports a fire in a manhole on Parkton Road shortly after 9 p.m. was followed rather quickly by people losing power between the MSPCA and the Jamaicaway.

At 3:39 p.m., David Ziegler-Voll tweeted:

Holy shit just saw 10 ft flames and smoke shoot out of a manhole cover on Atlantic Ave. across from South Station

Dale Cruse then added:

My girlfriend at S. Station said manhole cover smoked and exploded. Fire shot out while homeless man watched, like, "ain't no thang".

Stanley Staco reports multiple manholes exploded around 7 p.m. in the area of D Street and West Broadway. NStar estimates 11 p.m. for power restoration