An independent panel of scientists says two government-issued studies can't show if people were harmed by toxic pollution from Fort Detrick contaminating the ground water, but further studies are unlikely to answer lingering questions about the health impacts of the cancer-causing chemicals buried decades ago at the Frederick military base.

In a review sponsored by the Army, a committee of environmental and health experts with the National Research Council took issue with a study by the U.S. Agency for Toxic Substances and Disease Registry, which concluded that tainted ground water seeping out from Detrick's Area B was "unlikely to have produced any harmful health effects, including cancer."

The research council scientists said that because there had been little or no water sampling done before 1992, when toxic chemicals were discovered in residential wells near the base, it's impossible to reconstruct residents' past exposures. With such essential information lacking, the expert panel said, the federal study should have declared that the tainted ground water posed an "indeterminate public health hazard."

The Army has been under pressure from local activists and a former evangelist from Florida over toxic substances it disposed of and tested at the 1,200-acre base in Frederick. From World War II until 1969, biological agents were developed and tested there, and a 399-acre tract known as Area B was used as both a proving ground and a dump for castoff laboratory equipment and materials, including toxic chemicals.

Unsafe levels of two cleaning solvents, trichloroethylene and perchloroethylene, both carcinogens were discovered in wells just off base in 1992. High levels of the chemicals also showed up in a creek that flows past the base in the late 1990s. The Army has since excavated and removed chemical drums and almost 4,000 tons of contaminated soil. Under pressure from state officials, the Army agreed in 2010 to conduct more monitoring and cleanup under the supervision of the Environmental Protection Agency.

The National Research Council reviewers endorsed a study by the state and Frederick County health departments that found no evidence of cancer clusters in the community surrounding Fort Detrick, even though the lymphoma rate among nearby residents was higher than the statewide average. The health agencies' study was limited by its reliance on officially reported cancer cases, the scientific experts said, but anecdotal illness reports submitted by residents weren't verifiable or reliable enough to use. As for the higher lymphoma rates, the research council team suggested that might be at least partly explained away by the Frederick area's higher-than-average population growth at the time.

The National Research Council review is unlikely to please local activists or the former evangelist, Randy White, who has hired his own experts and pressed government officials to investigate claims that biological and chemical substances tested and disposed of at Detrick caused cancers in the surrounding community. White's children grew up within a mile of the base, and his ex-wife and daughter died of cancer.

The scientific panel said further studies wouldn't be much use unless new information about past exposures turned up. Instead the experts suggested that residents' fears for their health are founded on a legacy of mistrust over the secret research conducted at the 1,200-acre installation. The panel recommended the Army work harder at communicating with the community and try to build trust through activities beyond the health reviews.

Col. Allan Darden, Fort Detrick garrison commander, issued a statement thanking the research council and all the federal and state officials involved in studies of the base's contamination impacts.

White said he was glad the research council review had found fault with the federal ground-water contamination study, but disappointed that the health department's investigation of cancer clusters could only look back seven years because of limitations with the state's cancer registry.

White called it a "tremendous slap in the face" for Frederick residents and said he planned to file a lawsuit shortly seeking additional data that he contends the Defense Department has been withholding.

Maryland's Democratic Sens. Ben Cardin and Barbara A. Mikulski issued a joint statement calling the research council review "insightful and informative" and urged moving ahead quickly with cleanup of remaining contamination at the base to alleviate residents' health concerns.

Baltimore Sun reporter Matthew Hay Brown contributed to this article.