State officials have halted St. Mary's County's review of a proposed subdivision because munitions buried on the Oakville site by a defense contractor in the 1950s may not have been completely removed.

"Though many of the areas identified . . . were cleaned up and the unstable explosive hazardous wastes destroyed . . . there are still areas that need further investigation," said Amanda Sigillito, an acting administrator with the Maryland Department of the Environment, in a letter to St. Mary's County.

Virginia developer Robert S. Gollahon, of King George, wants to subdivide the property into 153 lots and build single-family homes in the northern section of the property, a 792-acre site south of Route 235 near Oakville. He plans to create at least five farmstead lots on the southern section.

Gollahon's plans were under review by the St. Mary's Department of Planning and Zoning, but temporarily have been put on hold while the state seeks additional cleanup of the northern section of the property, and determines why the cleanup was not completed.

"Until we have been assured that the site has been properly assessed and determined to be clean, the site will remain on the State's master list of potential hazardous waste sites," Sigillito wrote in a June 9 letter to Thomas Russell, the county's former director of the Office of Environmental Health. Russell now works for a county sanitary commission.

"I was very shocked when I talked to MDE and was told that the cleanup hadn't been all done," Russell said. "I certainly was under the impression that a good-faith effort had been made to get it all."

The site of the Gollahon subdivision was owned in the 1950s by Hunter Chemical Co. and Federal Ordnance Corp., which manufactured test detonators for the military. Thiokol Corp., a Utah-based company that manufactures solid rocket motors for NASA and the military, bought the property in 1959 but never used it. Thiokol, a division of Cordant Technologies Inc., sold the site in January to Gollahon.

In 1990, Cordant surveyed the site and discovered the buried ordnance, apparently manufactured by Hunter and Federal. Cordant officials said they worked closely with state officials and completed the disposal in June 1995.

Human Factors Applications, a Waldorf-based munitions disposal company, was hired by Cordant in 1992 to find and dispose of thousands of short, pencil-thin detonators filled with explosives buried at the site, according to Richard Wood, a supervisor with Human Factors.

Wood said he supervised the disposal of the explosives, obtaining an emergency permit from MDE to blow up the detonators on site because state law prohibits their transport.

By the spring of 1994, Wood said he and his workers had disposed of 1,360 pounds of detonators. Then, Wood said, Thiokol officials told him to stop the disposal work even though it had not been completed.

"They told us we had to cease," Wood said. "I'm not surprised [the detonator issue] came up again because [cleanup] wasn't finished."

Daniel Hapke, senior vice president and general counsel for Thiokol, disputes Wood's account and said Human Factors Application had indicated the cleanup was completed.

"We find their statements now to be inconsistent with paper reports at the time indicating the work was done," Hapke said. These records submitted to Thiokol showed all 792 acres had been cleared of buried munitions, Hapke said. Neither Hapke nor Wood could provide copies of those reports.

Now Thiokol has subcontracted Human Factors Application to help identify areas where more munitions may be buried, Wood said. Wood said his company has not been hired to dispose of additional munitions that may be found.

In a recent review of potential hazardous waste sites across the state, "we raised our concerns with the state fire marshal" about the Gollahon site, said Quentin Banks, a spokesman for the Maryland Department of the Environment.

Banks said a routine review of reports on hazardous waste sites filed with the state indicate "there was no closure on the cleanup" of the Gollahon site. The state fire marshal must inspect the site and determine it safe and free of munitions before the land can be developed, Banks said.

Harry Knight, permits coordinator for the St. Mary's Department of Planning and Zoning, said Gollahon's subdivision plan is scheduled for a hearing before the county's planning and zoning commission on Aug. 9. County officials will ask for a status report at that hearing.

Gollahon did not return telephone calls to his office.