So, you're a hard-working person living in a poor neighborhood struggling to make ends meet, and someone knocks on your door one day with quite a deal: The person offers to rework your lawn -- which is contaminated with lead -- tilling it, adding fertilizer and seeding it.

The work will cost you nothing. In fact, you'll get food coupons as an incentive to participate.

So, what's the catch? The "fertilizer" is actually what the industry likes to call "biosolids compost." Most folks call it sludge. It's the end-product of a sewage treatment plant.

The person at your door is working for a government-funded study that is attempting to determine whether spreading that sludge on your yard and growing grass will protect your children from exposure to lead.

But that person didn't tell you that there are serious questions about how safe sludge itself is.

Thomas Burke, a professor at the Johns Hopkins Bloomberg School of Public Health and chairman of a 2002 National Academy of Sciences panel, criticized the lack of science behind federal sludge regulations.

"There are potential pathogens and chemicals that are not in the realm of safe," Burke told The Associated Press. "What's needed are more studies on what's going on with the pathogens in sludge -- are we actually removing them? The commitment to connecting the dots hasn't been there."

Instead, the government is studying to see whether sludge application has any benefits. But these studies, as an AP article by John Heilprin and Kevin S. Vineys found, neglected any medical follow-up of the residents.

So the researchers can say with confidence that the levels of bioaccessible lead dropped after the yards were treated, but they cannot say whether there were any medical repercussions, positive or negative, as a result.

The study in Baltimore examined by the AP, and another like it in East St. Louis, Ill., are troubling on a number of counts.

They targeted poor, largely black neighborhoods. Study participants were not told what the sludge actually was -- it was described only as commercially available fertilizer.

"They were told that it was composted biosolids that are available for sale commercially in the state of Maryland. I don't think there's any other further disclosure required," Rufus Chaney, an Agriculture Department research agronomist who co-wrote the Baltimore study, told the AP.

Informed consent is basic to any kind of human experimentation -- and though the study was done on lawns, this was most certainly human experimentation.

Researchers suppose that children living in these homes and playing in these yards will be safer. Studies of the yards support that hypothesis, but there is no way of telling whether the properties in the sludge that trap lead in dirt do anything to protect exposed children in real-world circumstances.

The absence of informed consent about the potential dangers of sludge and the lack of medical follow-up are unconscionable.

Such irresponsible and unethical scientific undertakings should not be allowed to continue.