A survivor of the 2023 Maui wildfires, carpenter Liam O’Connor, has developed a modular underground bunker system that withstood test temperatures exceeding 1,500°C for six hours. The design, now under joint development with British engineering firm Arup, could redefine fire-resistant infrastructure in an era of escalating wildfire risk.
O’Connor, who lost his home and workshop in the Lahaina fire, spent the past year refining a passive cooling system that uses phase-change materials and aerogel insulation to maintain interior temperatures below 35°C even when the exterior is engulfed in flames. “I watched everything I owned turn to ash in minutes,” he said. “But this bunker, buried 4 metres deep with a ceramic-iron alloy shell, stayed cool enough to store food and electronics.”
Arup’s team of structural engineers and materials scientists has validated the bunker’s performance in their own lab. “We subjected a prototype to a propane flame front simulating a 1,500°C wildfire for six hours,” said Dr. Elena Rossi, Arup’s lead fire safety engineer. “The internal temperature never climbed above 32°C, and the structural integrity remained pristine. This is a game changer for communities on the fire front.”
The partnership aims to scale production to a prefabricated unit that can be installed in 48 hours, costing between £15,000 and £30,000 depending on size. Each unit is equipped with solar-powered ventilation, a week’s supply of water, and a satellite communicator.
“We are not advocating that people live underground,” Rossi added. “But as a last-resort shelter when evacuation is impossible, this system provides a viable survival option. With fire seasons lengthening and intensifying, the need for such solutions is urgent.”
Climate data underscores that urgency. Global average temperatures have risen 1.3°C above pre-industrial levels, and the area burned by wildfires annually in the United States has doubled since the 1980s. The UK’s own fire risk is rising; the Met Office now predicts a 30% probability of a 200-hectare wildfire in southern England by 2030.
O’Connor’s bunker is not a panacea, but it represents a tangible adaptation to a changing planet. “I don’t want anyone to have to go through what I did,” he said. “If this bunker saves one family, it’s worth every pound and every hour I spent welding that shell.”
