A toxin painted onto floor joists of new homes in Colorado is at the center of a lawsuit filed last week in Weld District Court. A Denver attorney, on behalf of two Firestone families, sued Seattle-based Weyerhaeuser Company for distributing floor joists coated with a formaldehyde-based resin. The resin was intended to make the joists flame-resistant, but it resulted in residents breathing in the toxins, requiring a hasty exodus from their homes, the lawyer says. “For anyone who’s been in a home that has this toxin on their joists, you smell it immediately,” said Mark Nelson, the Denver attorney who filed the lawsuit.