This is from an old PC post. What is written about the lead contamination is very basic, but later articles had city officials citing the lead issue (seven figures worth of cleanup in 1993, if I recall) and the nos factor making the place a non-starter for a stadium unless there was three years lead time.
http://www.washingtonpost.com/wp-dyn/content/article/2005/12/02/AR2005120202068.htmlSaturday, December 3, 2005; A01
Several council members told Reinsdorf that if baseball did not agree to the city's demands, they would push to move the project to a site adjacent to Robert F. Kennedy Memorial Stadium. That location could save the city more than $100 million, some council members have said.
But that option would require a costly environmental cleanup of the site and federal and congressional approval, a process that could mean long delays before construction.
The land is owned by the National Park Service and leased to the District at no cost. The 50-year lease, which ends in 2038, allows for only one stadium on the 200-acre site. Building a new complex would require Congress to amend the 1957 law that authorized the stadium, said John Parsons, associate director for the Park Service's National Capital Region.
The project also would require an environmental impact statement and approval from the Park Service, the National Capital Planning Commission and the U.S. Commission of Fine Arts, Parsons said.
He said the whole process could take two to three years. "That's quite a bit different than their existing circumstance because the other proposal is not on federal land," he said.
An environmental impact study completed in 1993 found potentially harmful lead contamination in the soil.