Polystyrene is the chemical compound that makes up styrofoam, which is used for packaging and insulation. But it’s not the most environmentally friendly.

By one estimate, 40 million tons of polystyrene were produced globally in 2024, leaving millions of tons of plastic waste. The search for an earth-friendly alternative has led researchers to dig deep and come up with an unlikely solution: fungus. The BBC’s Anna Holligan has this story.