Somewhere along the Bush River at the water's edge of Aberdeen Proving Ground, four white barrels sit next to a green storage tank in a thin grove of trees.
Army environmental officials suspect the containers hold what's known as fog oil, or possibly other debris from a long-abandoned program testing how to obscure the enemy's vision.
The Army will open one of the barrels as one of more than a dozenminor cleanup projects planned for the federal fiscal year that began Oct. 1.
The projects are part of APG's 30-year plan to clean up the ecological mess left by decades of weapons testing and waste dumping before standards were established to protect the environment.
Environmental officials maintain a list of projects that can be completed within a year, typically for less than $2 million.
"These aregenerally solid waste management units that have been targeted for quick action," said Ken Stachiw, chief of APG's environmental engineering and natural resources office. "They are a smaller order of magnitude."
The fog oil project falls under a $28.2 million base-restoration fund. The fund is 28 percent larger than the $22.1 million spentlast year.
APG environmental officials have separate plans to deal with what's inside the barrels, depending on whether the contents are liquid or solid, toxic or harmless, leaking or stable.
"If we don't have a whole lot of information, we have to plan for as many contingencies as possible," said John Wrobel, an APG environmental engineer who manages several cleanup projects at the base.
But they don't mark the site on public maps for fear of attracting souvenir seekers who might spill hazardous materials into the river.
"We have anidea of what's inside, but we want to treat every situation as something we don't want to expose people to," Wrobel said. "People see these things as attractive nuisances and might cause harm to themselves or the environment."
APG has identified about 350 sites stretchingeast from Spesutie Narrows to Carroll's Island, a Baltimore County peninsula that forms the base's western border.
"How you count the sites is a difficult process," Wrobel said. "One building can have different sites. A chemical drain line could be counted as one and an underground sewer line could be another."
The sites have been divided into 13 geographical study areas.
The "quick-hit" fund allows APG to take immediate action to resolve obvious problems at some sitesthat otherwise are part of decades-long cleanup plans.
For example, at a storage area in the Edgewood section of APG at the edge of the Bush River, the Army plans this year to seal a vault containing Adamsite, a war fare agent that causes vomiting.
The same site includes an underground dump where corroded barrels of Adamsite have contaminated the soil since the 1970s. The dump is considered a major cleanup project, one of hundreds that helped put the Edgewood area on the U.S. Environmental Protection Agency's national Superfund list.
AnAPG study in July estimated that the cost of treating poisoned rivers, creeks and ground water, disposing of buried chemical weapons agent, stabilizing hazardous landfills and digging up contaminated soil could exceed $800 million by 2010.
That figure is $200 million morethan projected in a similar study completed last year, reflecting the most expensive alternatives for cleaning up the O-Field dump in theEdgewood area, where mustard gas agent and other munitions are buried.
The annual list of minor clean up projects allows the Army to eliminate or limit some sources of contamination.
Plans this year include removing soil contaminated with PCBs, DDT and chemical solvents throughout the base.
The Army also intends to stabilize soil conditions at several dumps where erosion has caused or threatened contamination of ground water and the Gunpowder River.