The fire broke out at WA Splashback coloured glass specialists about 11am after an accelerant ignited, setting the premises and the 33-year-old employee on fire.
Employees from neighbouring businesses witnessed the fire and said seeing the man with burns to the majority of his torso was terrifying.
Hitesh Shah, who owns the business next door, said the WA Splashback receptionist and all the employees started running out into the car park shouting ‘there’s fire, someone call an ambulance and the fire-fighters’.
‘I called the fire fighters and someone else called the ambulance,’ he said.
‘We all came out and we saw the blaze coming out of the roller door and on top of the building.
‘I saw the guy who was burnt; he was stripped naked and washed down with water.
‘Those images will stay with me now; it’s going to disturb us for a while.
‘It was horrible.’
Mr Shah said the experience made him more aware of the importance of safety measures in the workplace.
‘If the fire would have happened in my place the whole building would have come down because we work with fabric,’ he said.
‘For the safety of people I have to rethink my procedures and have an evacuation plan in place.’
The 33-year-old Balga man was treated inside WA Stage School by receptionist Lynne Keating while waiting for an ambulance.
Ms Keating said the man staggered in and sat down before they poured more water over him.
‘His skin was peeling off his arms so we got wet towels and I put water over him,’ she said.
‘He was really not with it.
‘I had to hold him on the chair; he was basically falling off it.
‘It was terrifying.’
Ms Keating said when the ambulance arrived smoke was billowing out from the back of the studio.
‘It was just black and it was hard to breathe,’ she said.
‘It was shocking and I was shaking.’
He said the man was taken to Royal Perth Hospital in a stable condition.
A Department of Fire and Emergency Services spokesman said the damage bill was estimated at $300,000.