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A Darwin man almost died after an angle grinder bounced back onto him and slashed his face, throat and sternum.

The 71-year-old was renovating an industrial shed at the Darwin suburb of Winnellie, when the 230mm (9-inch) grinder fell on him earlier this year.

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“The worker was standing on a ladder and cutting steel wall frames above his head when the incident occurred,” NT WorkSafe said on Tuesday.

NT WorkSafe issued a warning about the danger of this particular grinder.

A 230mm angle grinder should only be used after “a risk assessment to identify alternative tools or methods of cutting”, it said.

“Some companies in the Northern Territory and across Australia have implemented voluntary bans of nine-inch angle grinders on their worksites due to the high number of serious injuries and deaths that have occurred.”

The worker had initially used a 127mm (5-inch) angle grinder to cut the steel frames before switching to the larger grinder.

“The metal frame may have sagged due to the previous cuts made, and pinched the cutting disk potentially contributing to the kick-back,” NT WorkSafe said.

“The worker was not in a stable position to control the grinder as he was standing on a ladder with the grinder cutting above his head.

“The increased power, torque and size of 9-inch grinders makes them more difficult to control compared to smaller grinders or other cutting tools.”

The extension lead that the angle grinder was plugged into may also have contributed to the incident, NT WorkSafe said.

“This may have caused a fluctuation of the electrical current with the grinder unexpectantly stopping and starting, potentially causing a kick-back.”

People using these tools are urged to ensure proper footing and balance, to use clamps or props to prevent upright or hanging items from sagging while they are being cut, and to avoid the modification or power tools.

Workers should also ensure the capacity of any electrical leads match the power requirements of the tool.