The Environmental Working Group on Monday rolled out its guide to the chemicals lurking in thousands of household cleaning products and the potential dangers they may pose to humans and the environment.

Just as it did with cosmetics in 2004, the nonprofit industry watchdog EWG has tracked down and assessed risks associated with more than 1,000 ingredients — many of them not actually listed on the packages — in more than 2,000 products we use to keep dishes, clothes, bathrooms, kitchens and other parts of our homes clean and sweet-smelling. In addition to extracting information about ingredients from company Web sites and other sources a consumer isn’t likely to consult, the EWG team drew data from 15 established databases to build toxicity profiles for products.

The report finds that among the products evaluated, “some of their ingredients are known to cause cancer, blindness, asthma and other serious conditions. Others are greenwashed, meaning that they are not, as their ad hype claims, environmentally benign. Still more hide the facts about their formulations behind vague terms like ‘fragrance.’”

And this: “Some 53 percent of cleaning products assessed by EWG contain ingredients known to harm the lungs. About 22 percent contain chemicals reported to cause asthma to develop in otherwise healthy individuals,” according to the report. Yet, the EWG notes, the federal government doesn’t require manufacturers of such products to list all their ingredients.

The report assigns each product a letter grade; not surprisingly, given EWG’s disdain for most things chemical, the F’s, at more than 1,000, far outnumber the 73 A’s.

The report was a yeomanly task, and the EWG does a thorough job of explaining its methodology. But it’s still surprising to read the write-up for an F-earning item such as Clorox Clean-Up bathroom cleaner (which, I should disclose, is a product I purchase) and find that the supporting evidence suggests cause for only mild to moderate concern for health risks (and no concern over cancer risk) — and also that the product did a good job of disclosing its ingredients.

And I'm not convinced that air fresheners such as those made by Glade and Air Wick should be included in the EWG’s “Hall of Shame” because they can be used as inhalants. Whose fault is it that people misuse these products by huffing them for recreational highs?

I’m similarly conflicted about some products receiving low marks because they’d do severe harm if a child ingested them. Isn’t it grownups’ responsibility to keep such products out of a child’s reach? Still, the report serves as a good reminder to handle these products with care if you do choose to use them.

Having quibbled, I do think this guide offers helpful information. And I value some of the safety alerts sprinkled throughout, such as this about Drano Professional Strength Kitchen Crystals Clog Remover:

The label says this product can severely burn eyes and skin and cause blindness or even death. Drano Kitchen Crystals may remain in the drain after use, creating an extreme hazard. Using a plunger could cause caustic splashback. Pouring any other product down the drain might trigger a dangerous chemical reaction. The label warns purchasers to “keep water out of can at all times to prevent contents from violently erupting or boiling out.” Yet unsuspecting consumers have been known to store it under the sink.

I did not know about that, and I am glad for the heads-up.

The guide is available free online. A wallet-size grocery-store version is available via the site for a $5 donation.