PANAMA CITY - Since the United States deployed large numbers of troops to protect the Panama Canal at the outset of World War I, thousands of acres of land have been contaminated by unexploded grenades, bazooka shells and other munitions.

In the last 20 years, nearly two dozen Panamanians have been killed and many others injured on or near the U.S. military's three practice ranges by explosives that detonated after being stepped on or picked up, Panama's Foreign Ministry said. Four years ago, a member of the U.S. Navy SEALS was badly injured during maneuvers when a discarded shell exploded under his feet.

Today, the question of just how much of the hazardous weaponry the U.S. military is responsible for cleaning up has become one of the most contentious issues between the United States and this small country as they set the stage for Panama to assume control of all properties used by the U.S. military here and take over the administration of the canal by noon on Dec. 31, 1999.

"We really do not know what the United States is doing. They are giving us very little information," said Sayda de Grimaldo, the Panamanian government official charged with overseeing the condition of U.S. military properties. "There never was a commitment to take care of the environment and manage the resources. . . . The military is here to complete its mission and does not care what happens afterwards."

The U.S. military's Empire, Balboa West and Pina ranges cover more than 37,000 acres of mostly rain forest, about one-third of which has been used exclusively for weapons training. The area has been littered with munitions from various conflicts of this century -- mortars from World War I, bazooka shells from World War II and the Korean War, and modern-day antitank rockets. Five years ago, 70 depleted uranium projectiles were stored briefly on one of the ranges.

Beginning in the 1920s and lasting through the Vietnam War, the military also used other swaths of land here to test, stockpile and dispose of chemical weapons, among them the poisonous mustard and phosgene gases and the defoliant Agent Orange.

An estimated 20,000 people, mostly peasants, live in small towns surrounding the ranges, a number that is expected to grow to about 100,000 within the next 25 years. Despite signs warning "EXPLOSIVES KILL ANYBODY, DO NOT TRESPASS," residents cross the ranges to go fishing in nearby waters, collect scrap metal or plant crops.

The Panamanian government says it wants the United States to adhere fully to the spirit of the Panama Canal Treaty of 1977 and to conduct thorough environmental assessments of the ranges, turn over all available records of how the military used the land and carry out an extensive cleanup -- even if it entails working beyond the December 1999 deadline.

The U.S. military, however, says much of the land is inaccessible because it is mountainous and covered with dense tropical jungle. It says the terrain could heighten the safety risks for those searching for explosives.

Military officials also contend that there are technological limitations to clearing the area of munitions and that such a project would irreparably damage the canal watershed, which is not only vital to the functioning of the transoceanic waterway but contains rare flora and fauna.

"We are attempting to the best of our ability to meet the requirements of the Panama Canal Treaty, and we feel confident that with proper precaution and care the range areas can be a safe, valuable resource for Panama," said Col. Michael J. DeBow, deputy chief of staff and engineer at the U.S. Southern Command here.

The 1977 treaty, which stipulates that the United States return all military facilities to Panama by 2000, says: "The United States must gather and provide information concerning environmental hazards caused by its activities in Panama, it must consult and cooperate with the government of Panama in addressing those hazards [and] it must carry out [an] environmental impact assessment. . . . U.S. obligations also include the duty to clean up environmental hazards and the duty to provide compensation for irremediable environmental damage."

The Panamanian government says that in addition to failing to turn over complete environmental records, the United States is trying to skirt the treaty's environmental requirements by falling back on the word "practicable" contained in an earlier section of the implementation agreement. "The United States shall be obliged to take all measures to ensure insofar as may be practicable that every hazard to human life, health, and safety is removed," the passage reads.

A preliminary plan recently presented by the U.S. Southern Command to Panama calls for clearing munitions and other debris from 548 acres of the estimated 6,000 acres most heavily affected by weapons contamination. The plan also specifies that the cleanup would deal only with materials found on the surface, saying that detection technology cannot distinguish between buried scrap metal and unexploded devices.

Particularly troubling, according to the Panamanian government, is that U.S. officials at this point have not committed to continuing the cleanup initiative beyond the 1999 treaty deadline.

Cleanup did not begin in earnest until mid-January and is expected to draw to a close next month when the dry season usually ends. This will leave next year's dry season for the military to complete its environmental work.

The military says that in the last month it has cleared almost 90 acres, destroying 250 explosives and removing an estimated 80,000 pounds of scrap and target metal. The military also has been conducting site studies to gather more information about the extent of the contamination. But it may run out of time. The cleanup "got off to a slow start. It was not on the radar screen," one U.S. official said.

"In Panama, the Pentagon does not want to set a precedent for the cleanup of overseas bases, despite its obligations," said John Lindsay-Poland, director of Latin American programs for the Fellowship of Reconciliation, an American peace group that has been involved in urging the U.S. government to clear the ranges. "The U.S. military and policymakers were in denial about it for many years. Washington is trying to keep it cheap."

Panama's Grimaldo, who heads the environmental department of the Interoceanic Regional Authority, the government agency monitoring the condition of the military properties, said, "The environmental responsibility of the United States should not end in 1999. The two governments should agree on a mechanism to extend that responsibility."

U.S. Ambassador William J. Hughes, who describes the range cleanup as "probably one of the stickiest issues we are dealing with here," said that while the United States believes it can comply with the environmental responsibilities of the canal treaty within the next 21 months, "the parameters of what those responsibilities are are vague. We need to come to closure on this issue."

Working with Panama's foreign minister, Hughes convened a committee made up largely of Panamanian government officials, scientists and environmentalists who traveled to the United States last fall to meet with experts at military ranges that are being cleaned up. The ambassador said efforts also have been stepped up to supply Panama with more documents about the ranges, and that he hoped a consensus on a comprehensive plan could be reached within a month or so.

Col. DeBow said the United States would erect barriers around portions of the ranges and post warning signs. He said the military is committed to an educational program that would involve distributing cards that identify the types of munitions believed to be on the ranges.

The Washington Post