SINGAPORE - A mechanic was injured and another went to the hospital for checks after a compressed natural gas (CNG) cylinder malfunctioned at a workshop in Ang Mo Kio.

Workers at Esteem Performance car repair and maintenance workshop at 5033 Ang Mo Kio Industrial Park 2 were clearing the cylinders at around 10am on Thursday (June 22) when a valve came off one of them, a workshop spokesman told The Straits Times on Thursday afternoon.

An eyewitness told Shin Min Daily News that a workshop employee had lifted a cylinder when it malfunctioned and hit the man before flying into the roof and hitting a car.

It is believed that the pressure had built up in the cylinder, causing it to rocket into the roof.

The Singapore Civil Defence Force told ST it was alerted at 10.45am. A man in his 40s fractured his left leg and was taken to Tan Tock Seng Hospital.

The workshop spokesman told ST at around 4pm that he was in Tan Tock Seng Hospital with the two victims, one of whom was waiting to be operated on.

"He is quite badly injured," said the spokesman, who is in charge of the CNG cylinders for a project. "Another employee came into the hospital for checks."

He said the staff were in the midst of clearing all the cylinders for disposal, when the valve came off from one particular tank which had been there "for a couple of days".

"The Ang Mo Kio workshop is closed for the day," said the spokesman. "We're now getting our guys to double check on all other cylinders to ensure this thing does not happen again, and taking extra measures to prevent it."

He said they would mount the CNG cylinders on straps and ensure that cylinders are emptied.

Asked about the damages wrought, the workshop spokesman said the cylinder made a hole in the roof and hit a car belonging to a neighbour.

He said the company does not have an idea yet of the cost of damage from the accident, but said they would claim the damages from their insurance plans.