Your house might look nice after a Saturday-morning cleaning blitz—but is it healthy?

Well, that depends on what you used to achieve all that sparkly, shiny good-smelling-ness. Based on a recent report from the nonprofit Environmental Working Group, the odds are pretty good that the cleaning products you used pose some serious health and environmental risks.

To prepare its “Guide to Healthy Cleaning” (find it at www.ewg.org), EWG analyzed 2,109 cleaning products—laundry detergents, toilet bowl cleaners, stain removers and dish soap—evaluating them for ingredients linked to cancer, reproductive and developmental disorders, asthma, allergies and other health problems.

It was no easy task; according to EWG, “Just seven percent of cleaning products adequately disclosed their contents. To uncover what’s in common household cleaners, EWG’s staff scientists spent 14 months reading product labels and digging through company websites and technical documents. We researched ingredients and contaminants in 15 government, industry and academic toxicity databases and numerous scientific and medical journals.” The resulting data base lets users search by product category or by specific product. Each product is given a grade from “A” to “F.”

The findings are sobering. More than half the products analyzed contained ingredients shown to harm lungs; almost one-quarter contained asthma-causing ingredients. The researchers also found numerous carcinogens and hormone-disrupting ingredients in many common cleaning products. Among the worst offenders, the products EWG recommends consumers avoid completely: air fresheners, which typically contain harmful synthetic fragrances; antibacterial soaps, which can lead to the development of drug-resistant bacteria; fabric softeners and dryer sheets, which often contain ingredients linked to asthma and allergies; and drain openers and oven cleaners that can burn the eyes and skin.

The group also warns consumers to be wary of products labeled “natural”; while some truly are, others are simply jumping on the green bandwagon but contain harmful ingredients or fail to adequately disclose their ingredients. (Just one example: several laundry products labeled “free and clear”—indicating they don’t contain fragrances or dyes—still earned grades of “D” or “F”.)

Even the most conscious consumers, EWG says, can find it challenging to evaluate just what products they’re using in their homes. “Ingredient labels are mandatory for food, cosmetics and drugs—but not for cleaning products,” the report notes. “Manufacturers aren’t required to disclose all ingredients in their cleaners and many don’t, including some ‘green’ cleaners makers.”

The group calls on consumers to pressure manufacturers to provide full ingredient lists and on lawmakers to toughen up disclosure requirements.