For the past 30 years, flame retardants have been found in every Canadian home, added liberally as a safety precaution to everything from mattresses and carpets to stereos, televisions and computers. Now Canada is poised to add flame retardants — or polybrominated diphenyl ethers (PBDEs) — to its toxic-substances list. If a draft proposal it is circulating is any guide, the federal government is expected to virtually eliminate some varieties of the chemical and place tight controls on others. Regulators are considering drastic action because laboratory studies using animals have linked the chemicals to behaviour changes that bear an uncanny...