Signs posted along the road here warn motorists not to stop. An isolated, wooded area - some 300 square miles along the Savannah River - is patrolled. This is part of the complex of federally run facilities across the nation involved in making nuclear weapons.
Since the original Manhattan project, which resulted in the first nuclear bomb for the United States, several of these ''bomb factories,'' as they are sometimes called, have been built. They have operated in a world largely unto themselves. Secrecy is the key word.
But in recent years, the US Department of Energy (DOE), now responsible for their operation, has come under increasing criticism for lack of candor about environmental problems, including nuclear waste, that the DOE says don't involve classified information.
* In 1980, DOE investigators reported they had had a hard time gathering data about allegations of a coverup involving leaks in high-level nuclear waste tanks at the nation's largest nuclear waste dump, near Richland, Wash. The investigators criticized DOE management policies at the DOE plant for having kept publicity about possible leaks ''to a minimum.''
* Last year the DOE was finally forced to admit what a congressional panel says the DOE knew since 1977: that some 2.4 million pounds of mercury had been discharged into the environment at a DOE-run plant near Oak Ridge, Tenn. And Steve Gough, whose 1981 report on the mercury was squelched by the DOE when he worked at the plant, says that files at the plant indicate the mercury spills were known ''in 1970 and perhaps earlier.''
* Now a former DOE engineer at the Savannah River plant here charges that the department has effectively kept the public from getting a clear picture of internal criticism of key environmental practices at the plant. Both the DOE's inspector general and a congressional subcommittee are investigating these charges, by William Lawless, who until last year was assigned to evaluate waste practices at the plant.
Mr. Lawless is also alleging massive misuse of funds on such construction projects at the plant as the huge, high-level nuclear waste storage tanks.
An internal report by Lawless that criticized nuclear waste policies at the plant, other previously nonpublic documents, two reports withheld by the DOE from a federal court and made available to the Monitor, and lengthy interviews with officials of the DOE and Du Pont, which operates the plant under a DOE contract, indicate a pattern of not making public some information critical of environmental practices here, even though the information is not classified.
DOE and Du Pont officials point out that Lawless has not accused the plant of unsafe operations. And they insist that the public is informed of relevant issues on a regular basis.
But there is increasing concern among some members of Congress and environmental leaders that letting the DOE decide what the public will and will not be informed about is not good enough.
And there is concern that a new DOE rule being finalized, which would allow the department to withhold certain unclassified material of potential use to terrorists, may also be used to cover up nonsecret environmental problems.
Outside scrutiny of nonsecret DOE practices at its nuclear facilities would provide more objective public assurance on issues of worker and public health and safety without compromising national security, critics say.
For example, at the Rocky Flats nuclear facility just outside Denver, there has been no outside investigation of concerns by some members of Congress and private citizens that workers' health is endangered due to exposure to plutonium. There has been strong criticism of the reliability of a study by an expert from another DOE facility.
''It's not that they (the DOE and their contract managers at the federal nuclear facilities) are evil, but they're human,'' says US Rep. Patricia Schroeder (D) of Colorado. ''Everybody's starting to catch on to the (DOE's) game that only the experts are qualified (to assess problems at the federal nuclear facilities) and then they name the experts.''
Issues such as worker health at the Rocky Flats plant should be assessed by ''somebody outside DOE's influence,'' she says. She suggests state departments of health be allowed to make studies at the plants.
Others have suggested giving the Nuclear Regulatory Commission (NRC) the same watchdog role over federal nuclear facilities as it has over private ones. And a legal battle is under way between environmentalists and the DOE to try to force the department to give the US Environmental Protection Agency (EPA) a greater voice in environmental issues at the DOE's nuclear plants.
''You've got the regulators sitting in the same house with everyone else; that's the problem,'' says Lawless of the DOE's responsibility to monitor itself. ''It's an organization thing. There's no one individual to blame.''
For the most part, the DOE operates with little EPA scrutiny. It is also outside the NRC's scrutiny. But the DOE merits such trust in operating largely on its own, department officials here contend.
''I'm responsible and I'm accountable,'' says Edward Goldberg, assistant manger for operations at the Savannah River plant here. ''We in the DOE have the expertise to monitor the heath and safety responsibilities. The safety of the plant is unparalleled.''
Melvin Sires, DOE assistant plant manager for health, safety, and environment says that NRC and greater EPA involvement ''would probably interfere with the operations.''
But former DOE engineer Lawless points to numerous instances when, he says, the public was not informed about nonsecret environmental questions.
A closer look at his criticism and the rebuttals from the DOE and Du Pont offer a rare insight into the thinking and operations at one federal nuclear weapons plant.
Next: Internal debates at the Savannah River nuclear plantm