In searching for better flame retardants for home furnishings—a large source of fuel in house fires—National Institute of Standards and Technology (NIST) researchers defied the conventional wisdom and literally hit a wall, one made of clay.

It wasn’t a dead end, but rather a surprising result that may lead to a new generation of nonhalogenated, sustainable flame retardant technology for polyurethane foam. The thick, fast-forming coating that the NIST team created has a uniformly high concentration of flame-inhibiting clay particles, and it adheres strongly to the Swiss cheese-like surface of polyurethane foam, which is used in furniture cushions, carpet padding, children’s car seats, and other items.