Pesticides known as pyrethrins and pyrethroids, long considered "safe," have exploded in popularity over the past 10 years. Unfortunately, so has the number of reported poisonings from exposures to these chemicals.

    Yet the federal Environmental Protection Agency, which collects this data and has a role in protecting public health and the environment, has been unconscionably slow in responding to the threat.

    An investigation by the independent, nonprofit Center for Public Integrity reports the number of human health problems linked to the pesticides, including severe reactions and deaths, rose almost threefold from 261 in 1998 to 1,030 in 2007. Experts agree those numbers are probably just a fraction of the actual pesticide-related exposures in a given year.

    The compounds appear in thousands of products, including anti-lice shampoos for pets and people, bug repellents, flea collars, automatic misting devices, lawn-care products and carpet sprays.

    Pyrethrins are derived from chrysanthemum flowers. Pyrethroids, their synthetic counterparts, replaced another class of pesticides that were originally derived from nerve gas.

    Both are generally believed to be less toxic than earlier generations of pesticides, but have become the focus of a growing number of reports of deaths and severe allergic reactions. The center reports that, last year, the compounds accounted for more than 26 percent of all major and moderate human incidents involving pesticides in the United States.

    Two years ago, the EPA ordered manufacturers to provide labels warning against using the pesticides without adequate ventilation. But the continued rise in the number of poisonings is proof that precaution is inadequate.

    For 15 years, the Food and Drug Administration has required warnings targeting the pesticides' possible effects on people with ragweed allergies. A few years ago, it made that language even stronger: "Ask a doctor before use if you are allergic to ragweed," the warning states. "May cause difficulty breathing or an asthmatic attack."

    An EPA spokeswoman said the agency had been planning a study on the health effects of pyrethrins and pyrethroids in 2010. In the wake of the center's findings, however, she will push for an earlier study.

    Still, it's disturbing the EPA was slow to act, especially considering that much of the data for the center's report came from the EPA and was obtained via the federal Freedom of Information Act.

    The Center for Public Integrity has done the public a great service.