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Key Facts Related to 2000 Soil Study


Summary Statement & Key Facts Related to 2000 Soil Study
Kennedy Krieger Institute and Johns Hopkins University

Some recent news accounts have inaccurately reported that researchers from Kennedy Krieger Institute and the Johns Hopkins Bloomberg School of Public Health spread "sludge" or "human and industrial waste" on the lawns of Baltimore neighborhoods as part of a 2000 research study. In reality, the research study mentioned in these reports used Eckology/Orgro, compost that includes Class A biosolids. This compost is made from sterilized Baltimore sewage sludge mixed and composted with wood chips and sawdust. This commercially available compost is available from the Baltimore City Composting Facility and has been used on the lawn at the White House, the grounds of the Naval Observatory where the Vice President resides, sport stadiums, golf courses, as well as the lawns and gardens in private residences.

This study was in direct response to those communities that were most heavily impacted by lead poisoning and was trying to give the community a means to reduce one source of lead exposure.

Below are key facts related to 2000 soil study.

1. Baltimore’s Lead Poisoning Epidemic:  Baltimore suffered one of the worst lead epidemics in the country at the time.  Hundreds of children were being treated for lead poisoning and the Kennedy Krieger lead clinic was one of the busiest in the country.

2. Neighborhoods in the Study:  The study was conducted in neighborhoods in Baltimore City where the soil lead levels were well above federally recommended levels.  Records from the City, State, and Kennedy Krieger’s own lead clinic consistently showed that these were the neighborhoods where the highest incidences of elevated blood lead levels were being reported.  Some of the yards selected were identified with the assistance of community leaders.

3. Safety of Compost Used:  The study utilized commercially available compost that is approved for general use.  It is widely available for commercial and residential use and has been used on the lawns of the White House, the Vice President’s residence, Camden Yards, golf courses, and homes throughout the area.  This commonly used product contained Class A biosolids.

More than 350,000 cubic yards of the same compost was sold in the 1990s for “unlimited” commercial and home use in the Baltimore region, demonstrating how widely it is used.   It should be noted that the Greening Committee of the Historic East Baltimore Community Action Coalition (HEBCAC) applied this same compost to yards and gardens as part of local beautification efforts prior to this study. 

This compost meets the highest federal and state standards for compost approved for use.  In fact, in Maryland, many of the state standards are higher than the federal standards.  We are not aware of any research before or at the time of the study – and indeed today – to suggest that the general use compost used in this study poses known risks to humans. 

Note:  If new scientific evidence arises to question the safety of Class A biosolids, Kennedy Krieger and Johns Hopkins certainly support and agree that further study by biosolids experts would be necessary.

4. Containing the Spread of Lead Dust: This study sought to reduce potential lead exposure through two methods:

a. Applying Compost: Compost had already been shown in previous studies to reduce the dangers of lead in soil.

b. Growing Grass: In addition to the compost, the study called for grass seed to be planted in the yards, which had been shown to provide an added layer of protection from contact with lead in the soil by reducing dust.

5. Study Results: The study results showed that the amount of “bio-accessible” lead in the soil – that is, lead that could poison kids – was down about two–thirds.  The grass cover was healthy, meaning that less lead, bio-accessible or not, could get tracked into homes in the first place.

6. Study Publication: In 2005, the results of this groundbreaking study were published in a peer reviewed journal and its success provided a tool to policymakers for cost-effective remediation of lead contaminated soil, in urban neighborhoods.

7. Medical Follow-Up: The research premise was to study by how much the compost could reduce the levels of “bio-accessible” lead in the soil. It was not to study the people affiliated with the study site.  All children were required by Baltimore City law to be tested for lead levels by their primary care physician, and the materials given to study participants encouraged them to have their children tested and advised them that they could get free blood testing.

Further, there was no need to conduct medical follow-up related to the use of the compost since there was no evidence then, nor now, that this commercially available, general use product posed any health risks.

8. Informed Consent: Participants signed a consent form which included very specific detail on the study, including the compost used.  As always in such studies, a qualified member of the study team walked through the details of the study with participants, and answered all questions.  Participants were given as long as they wanted to decide to allow their yards to be tested. 

9. Financial “Incentives”: Participants were given $10 gift certificates to local food stores in exchange for allowing treatment of their yards as part of the study.  Testing took time and they needed to be home.  The gift certificate compensated them for their time – a routine practice in most studies.

10. Community Involvement: As there was tremendous concern about the lead poisoning epidemic, many community organizations, such as Bea Gaddy’s Women and Children’s Center, Historic East Baltimore Community Action Coalition (HEBCAC) and Middle East [Baltimore] Community Organization (MECO) supported this study.

Updated News Coverage

Johns Hopkins Raps AP Story on Lead Experiment
Associated Press
June 13, 2008

AP "sludge" story: whoops...
Baltimore Sun
June 13, 2008

Recalling Farfel's Research
Baltimore Sun
May 1, 2008

Researcher Faces Outcry
Baltimore Sun
May 1, 2008

Sludge and Other Theories: Time to Think
Baltimore Sun
May 1, 2008

Treated Compost Not Same as Sludge, Maker Stresses
Baltimore Examiner
April 30, 2008

Hopkins' Hands Clean
Baltimore Sun
April 28, 2008

Editorial: Too Quick to Judge
Baltimore Examiner
April 21, 2008

Public Affairs media contact: Tim Parsons at 410-955-6878 or