Neil Kelly, from Bury, was using a high concentration of sulphuric acid to unblock a sink at a domestic property when the corrosive liquid erupted into the air.
The 52-year-old’s employer, City Response Ltd, was prosecuted by the Health and Safety Executive following the incident in Glencoe Close on 18 December 2009.
Trafford Magistrates’ Court heard that the worker had not been given appropriate protective clothing, training or supervision on how to safely use the sink unblocker, which was made up of 96 percent sulphuric acid.
The chemical erupted when he reached over the sink to turn on the tap, and it mixed with water in an exothermic explosion.
The acid hit the ceiling and rained down on him, burning through his paper overalls. He was off work for more than two months due to the extent of his injuries.
City Response Ltd admitted breaching the Control of Substances Hazardous to Health Regulations 2002 by not adequately controlling the exposure of workers to hazardous chemicals.
The company, of Oldham Broadway Business Park in Chadderton, was fined £5,000 and ordered to pay £2,965 in prosecution costs on.
Sarah Taylor, the investigating inspector at HSE, said: “City Response allowed one of its employees to use dangerous chemicals without anyone making sure he was working safely. As a result, he suffered severe acid burns to his face and body.
“The company should have made sure he used appropriate protective clothing, instead of the paper overalls which were dissolved by the acid. He should also have received training on using the chemical.
“Property maintenance firms must carry out regular checks on the work their employees are doing while they’re away from their normal base, especially if they’re expected to work with dangerous chemicals.”