Old photographs reveal clues to modern inquiry.

The faded sepia images slowly reveal their clues to the Roger Caswell's patient stares.

Long-ago recorded shapes and colors suggest earlier uses of the sprawling property on the shore of San Francisco Bay.

Caswell, Environmental Coordinator, for the Oakland Army Base, is a modern-day Dr. Sherlock Holmes. His goal is to track down the source and location of pollution at the former military facility.

Working in Command Historian Mike Bellafaire's work area Jan. 28-29, Caswell is making a thorough search of existing records of the old Army base, an operating MTMC facility until September 1999. Faded photos, many black and white, are spread haphazardly on a worktable. The facility is now in transition to new uses via the Oakland Redevelopment Authority.

"This might mean a difference of several million dollars to the Army when the allocation of responsibility plays out," said Caswell.

Caswell is working under the hypothesis that an oil-like pollution found at the site dates from a pre-Army use of the land in early 1941 and the years before. The Army took over control of the Oakland property in January of that year. Most tenants had 30 days to get off the property. The oil refinery got a little bit longer. With war looming, the Army began construction on the site that June.

"There used to be a waste oil reclaiming plant on the site," said Caswell. "From the old photographs we want to pinpoint the site of the plant and see if it is the same spot as the pollution."

The pollution became apparent in 1996. That is when oil eased up through the parking lot of Building 1, the base's former administrative building.

"This is the first we knew of the pollution," said Caswell. "The pollutant had the characteristics of volatile hydrocarbons. The residue from this plant is the largest single contaminated site on the base."

The focus of Caswell's search is photographs of early construction at the base prior to the Japanese attack on Pearl Harbor, Dec. 7, 1941.

"I'm trying to narrow the number of photographs and determine what happened to the refinery," said Caswell.

The Command Historian's photographs were brought to the attention of Caswell in a May 2000 issue of the newsletter "Wheels, Wings and Rudder," published by the San Francisco Bay Area Chapter of the National Defense Transportation Association. The newsletter had printed a press release from the Military Traffic Management Command that chronicled Bellafaire's review of boxes of historic materials and artifacts recovered from the Army base.

"There are photographs I've never seen," said Caswell, referring to the MTMC Headquarters collection.

"I've gone through everything on base."

For his part, Bellafaire is glad to be part of the solution.

"This is what a historian is all about," said Bellafaire. "We use the past to help explain or understand the future."

Well, how did it go?

Pretty well, said Caswell. He said the treasure trove of photographs provided excellent clues to land uses of the past. The work was so rewarding, Caswell cancelled his late Friday afternoon flight back to the West Coast and instead spent the rest of the day reviewing the yellowed, and often battered, photographs. The historic images were a rich source, indeed. Taken prior to World War II, the photos revealed new clues to a modern puzzle.