In mid-2015, Salisbury factory employee Sharon Vargas was having trouble operating a machine that uses a metal plate – heated to about 200 degrees centigrade – to press boot leather into shape.

When she used the method in which she was originally trained, the leather kept folding inside the machine.

According to the judgment of Industrial Magistrate Michael Ardlie, a colleague showed Vargas a shortcut to overcome the problem. It involved using wrists and forearms to activate the machine while holding the boot with her hand, removing her hand just as the heated plate came down.

But the first time she tried this new method, both her hands became trapped under the heated plate, and she was initially unable to hit the emergency stop button.

She was eventually able to free one of her hands and press the button, but had by then suffered third-degree burns.

Vargas underwent skin graft surgery at the Royal Adelaide Hospital, as well as hand therapy and mental health treatment, and had to take almost year off work.

She now works two hours a day, five days a week in another area of the company, but has a lack of feeling in her hands, which may require further surgery. She also suffers anxiety and depression.

RM Williams, founded by bushman Reginald Murray Williams and bought by global fashion giant Louis Vuitton in 2014, has been fined $90,000 in the Magistrate’s Court after an early guilty plea for failing to comply with a health and safety duty, exposing an employee to the risk of serious injury.

The company concedes the incident was similar to one in 2007 for which it was later convicted, in which an employee had two fingertips trapped and crushed in a high-temperature logo-stamping machine.

According to a summary of the defendant’s case in the judgment: “It is a fair criticism to say that there are similarities between this incident and the previous [2007] incident”.

A summary of the allegations made against the company within the judgment says the company was “not aware of the various ways in which its workers had learnt to defeat the safety measures in place”.

“It is a matter for grave concern that the worker, being a new worker on the plant, was being instructed in a practise which was positively dangerous and sought to defeat the machine’s safety measures.”

The company has since fitted all its Tow Puff mechanical presses with clear guards to prevent hands and arms being inside the machine before the heated press descends.

According to the judgment, the company conceded that there had been a failure to have an interlock guard in place on the machine, and a “breakdown in training and supervision” at the Salisbury factory.

“The training method should have been more formalised, with an emphasis on safety,” it reads.

“The problem arose when [Vargas] was shown a shortcut technique by a co-worker.”

According to the summary of the company’s defence, “a team leader at the time of the incident was disciplined because of his awareness of the shortcut technique and falsification of training records relating to the plant”.

It says RM Williams was “extremely remorseful” for the incident and had attempted to support Vargas during her recovery and return to work.

The company’s sentence was reduced by 40 per cent because of its “early plea of guilty, its cooperation, its demonstration of contrition and the installation of appropriate guarding together with the implementation of proper training and instruction”.

“The interlocked guarding makes it highly unlikely that such an incident could occur in the future,” the judgment says.

RM Williams employs about 350 people in its Salisbury factory.