In response to the dialogue about this issue, I have added some links that are a follow-up. Specifically, I want to address the science or scientific processes involved in this type of research. Here is the SOIL COMPOST STUDY TO REDUCE LEAD HAZARD FACT SHEET.

Here is the abstract or summary of the research experiment. The study was published in the peer-reviewed journal Science of the Total Environment. The journal is an international medium for publication of original research on the environment with emphasis on changes caused by human activities. It is concerned with changes in the natural levels and distribution of chemical elements and their compounds that may affect the well-being of the living world, or represent a threat to human health. Papers in applied environmental chemistry and environmental health sciences are particularly encouraged. This study falls well within the purview of this publication.

I do understand the environmental justice concerns of this research specifically with this research group, as noted by Francis Holland. I'm not dismissing his or others concerns. However, I think it is important that those who are most vocal about this issue demonstrate a basic comprehension of how this type of research is conducted and what this study found.

Let me break a few more things down.
In addition to Institutional Review Boards (see note in previous post), the peer-review process is another stop-gap for making sure appropriate procedures and ethical measures are followed in research. Research that is believed to be problematic is investigated and not permitted to be published. There are also number of professional reprimands for researchers are proven to be unethical or inappropriate when researching or reporting results.

The Abstract - rewritten
High lead concentrations in urban industrial areas are a big problem and can cause many health problems in people, but there is no one program to get rid of lead in soils, unless it is a big nasty spill from a company or factory. So there are many people who are exposed to lead in soil, but there is no feasible and affordable solution at hand. The researchers selected lawns in contaminated neighborhoods where the ground contained a fairly high concentration of lead which can get into the human and animal body systems. They used a commercially comparable compost, organic material from animals, that contained a fairly high concentration of iron and phosphate, and spread it over the lawns. Iron and phosphate can grab the lead in the soil and keep it from getting into the body system of people and animals. Iron and phosphate are also great fertilizers to improve the health and appearance of lawns.

The lawns were tilled, or dug up, and the compost was applied. They sampled the soil in the lawn several times to compare the levels of lead in the soil in various locations in the yard (near to the home vs farther away from the home) and many times over the course of the year. They compared the level of lead before the compost was applied and many times after the application.
At the end of the experiment, the lead concentration that can get into the body was much lower. The lower concentration of lead was more notable at areas closer to the home, where the risk of picking up lead was higher. At the more distant parts of the lawn, the treatment didn't lower the lead concentrations much, but there was always a lower concentration of risky lead in those parts of the yard. Plus, the lawns were healthier and more attractive at the end of the study. This research met its objective of finding a possible and feasible way of reducing lead in soil without having to dig up the whole yard and discard of the contaminated dirt in some undetermined place. This research is particularly important because it may provide an affordable solution to reducing lead poisoning risk in children.