Wheat bag started fatal bed fire, inquest hears An 80-year-old Sydney woman died in a unit fire which police believe started when a hot wheat bag set her bedclothes alight, the NSW Coroner's court has heard. Two other fires in Sydney homes may also have been caused by wheat bags, raising concern the commonly used therapeutic device is dangerous. The inquest into the death of Margaret Rae, a retired nurse, heard on Monday she died from smoke inhalation at her home at Oleander Parade, Caringbah on September 10, 2011. Margaret Rae: police believe she died after a heat wheat bag set her clothes on fire. The police officer charged with investigating the incident, Detective Sergeant David Glennan, said he had initially been at a loss to explain the cause of the fire. Then Ms Rae's brother and sister in law mentioned the 80-year-old's habit of using heated wheat bags, which are small fabric sacks with wheat grains sown inside, for warmth and to treat a hip condition. "It then occurred to me that the source of the fire was around the location of where her hip would have been in the bed," Detective Sergeant Glennan said. The wheat bag was the most likely cause, he said. I formed the opinion that on the night the fire took place, Margaret had most likely heated the wheat bag and put in her bed, had a few whiskeys and then become engrossed in her crocheting. I think she later noticed the smoke coming from her bedroom and she opened the door and was pretty quickly affected by the smoke. I think that she tried to get her car keys to get out but she didn't make it. A fire expert, Inspector Robert Jansen, told the coroner that after wheat is heated to a certain temperature, elements could continue to react and reach "combustible temperature." If a wheat bag was located in a bed, the heat might not dissipate and could set bedclothes alight, Inspector Jansen said. The inquest heard that two unit fires at Padstow and Darling Point occurred where heated wheat bags were used by elderly residents. In each case the residents suffered smoke inhalation but suffered no permanent injuries. Counsel assisting the coroner, Bronwyn Lorenc, said wheat bags were commonly used as an alternative to water bottles because they did not contain hot water, which could scald. There was little regulation of how the bags were made, including an absence of any requirement that the bags use fire resistant materials. "These products vary from handmade wheat packs sold at craft markets, to therapeutic heat packs manufactured especially for medical heat treatment," she said. There is no current Australian Standard relating to wheat bags, nor are there any current proposals . . . For home-made bags in particular, there may be no steps taken to reduce fire risk. The inquest, before coroner Paul McMahon, continues.