A wind turbine in the US state of Massachusetts is to be dismantled as soon as possible after reports that it was spinning “out of control” with debris flying from the machine.

Massachusetts Water Resources Authority (MWRA) which operates two machines at Deer Island, Boston, said the turbine was earlier this week subject to an urgent procedure to insert a braking mechanism to bring it to a halt.

The 600kW turbine – which has been out of service for about a year – “was locked in place. Although it’s too soon to speculate on what happened, it appears that this morning’s strong winds broke the braking mechanism and the turbine began to free spin,” MWRA said in a statement.

Passers-by called emergency services and told local media the turbine appeared “out of control”, with dramatic footage appearing to show debris flying from the rotor.

“I was scared out of my mind,” walker Melinda Ginches told NBC10 Boston. “We were right in the line of where the debris was falling. It was coming towards us.”

The water authority said “there is significant damage to the turbine and MWRA believes that the best course of action is to take it down so it no longer poses a danger.

“Staff are working to expedite the removal; however, it will involve a large crane, so it may take a couple of days to mobilise and begin the work.”

No details are given about the turbine on MWRA’s website, beyond the fact that it was installed in 2009 to help power the treatment plant.