The environment committee of Canada’s House of Commons has proposed a nationwide ban on “cosmetic” pesticides used on residential lawns to make them look greener and to kill dandelions, reflecting growing concern about the health effects of lawn chemicals, especially on children. Health Minister Allan Rock plans to propose legislation this fall that would overhaul the nation’s 30-year-old pesticide law. At the local level, dozens of Canadian communities have already banned or seriously restricted use of lawn pesticides. Chemical companies aren’t happy about the trend; two companies have filed suit in Canada’s Supreme Court against the small community of Hudson, Quebec, over its pesticide ban.