The warning comes from commercial insurer NFU Mutual, which claims the self-combusting tea towel phenomenon occurs when remains of oil and fat ctonimatinate fabrics made of natural fibres.
It said the remaining oil can undergo a chemical reaction with oxygen in the air, which releases heat, and in some circumstances this can lead to spontaneous ignition of the fabric initially as a smouldering process.
The reaction is believed to be even more likely when combined with heat such as that from tumble drying – especially when removed from the dryer and left in a pile, which offers “perfect conditions” of thermal insulation for the heat to thrive – and also if left near a heat source.
Oxidising detergent chemicals such as peroxide in stain remover can also cause the chemical oxidising reaction, with or without heat, NFU said.
Darren Seward, hospitality specialist at NFU, said: “Although tea towels may appear clean once washed, they may still have the remains of cooking oils and fats or chemicals on them that are invisible to the eye.
“If they are then put into a tumble dryer, the combination of heat, cooking fats and oxygenating chemicals from stain removing detergent products can create a chemical reaction and cause the towel to self-heat, smoulder and eventually catch fire.”
He added an unsuspecting mistake could put staff members in danger and cost a hotelier thousands of pounds if a fire were to start.
To try and prevent the issue, NFU advises hoteliers to wash tea towels at high temperatures to try to ensure that oils are completely removed.
The Wheatsheaf Inn in Rutland suffered severe fire and smoke damage after a blaze was caused by self-combusting tea towels.
After interrupting the tumble-drying cycle of tea towels the tenant left a number of very warm tea towels in the bottom of the dryer drum, said NFU. The first floor was ablaze 90 minutes later and the public house was masked in smoke, resulting in the business being closed for over six months.