The health risks from toxins such as lead in old paint or asbestos in walls are too often overlooked when homes are upgraded, according to a study on Sunday calling on governments to set tougher pollution rules. The report, by Canadian experts, said that retrofits of old buildings, such as insulation meant to save energy and limit greenhouse gas emissions, often released poisons that can be especially damaging to children. "Without sufficient care, retrofits...can increase the health risks," Theresa McClenaghan, executive director of the Canadian Environmental Law Association (CELA), told Reuters as she outlined a CELA project to limit health risks.