When Earthjustice and other environmental groups announced last week that they were suing several major household cleaner manufacturers, asking that they be required to list ingredients, I was mystified.

Don't they already?

It set me to rummaging under the kitchen sink for my cleaner of choice.

The first ingredient: "soap agents." I noted it wasn't merely "soap." The word "agents" sounded ominous.

Second: "soil suspending agent." These aren't ingredients. They're categories.

Third: perfume. As if I might spritz it on for a party.

Fourth: water. At last, something not likely toxic.

I checked another bottle. This one listed 2 percent sodium hypochlorite and 98 percent "inert ingredients."

The label also read, "Hazards to Humans and Domestic Animals." There were more instructions about first aid than how to use the stuff.

To be sure, it would be foolish to assume cleaners are benign. But this gave me pause.

After all, most people use buckets of cleaners. It's a $5 billion-a-year industry.

Manufacturers, meanwhile, have launched a voluntary "ingredient communication program" to take effect in 2010, though details are scarce.

Studies - and even product labels - suggest some of the chemicals can cause health effects, triggering asthma and allergies. "Not recommended for use by persons with heart conditions or chronic respiratory problems," reads a bottle under my sink.

A 2007 study in the American Journal of Respiratory and Critical Care Medicine concluded that cleaning sprays could cause 15 percent of adult asthma cases.

Other studies suggest links to infertility.

People are increasingly worried about cleaning chemicals, as sales of "green" cleaners attest. The Chicago research firm Mintel found that such sales quadrupled from 2003 to 2008 to $64.5 million. The firm predicts green cleaners will capture 30 percent of the market by 2013.

But you can sidestep all this. Make your own.

Last summer, Molly Rouse-Terlevich of Bryn Mawr held a party for about 20 women to learn how to do it.

She'd gotten materials from a national environmental health group, Women's Voices for the Earth, which joined last week's suit.

A year ago, the group used spring cleaning season and National Poison Prevention Week to launch an education campaign about the potentially harmful effects of household cleaners.