Down Under

The legacy of chemical-weapons testing at MacDill AFB and Hernando County Airport

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click to enlarge Chemical-weapons testing took place at MacDill in - the 1940s. The Pentagon expects cleanup of - affected sites to be complete by 2021. - GWENDOLYN RODRIGUEZ
Chemical-weapons testing took place at MacDill in the 1940s. The Pentagon expects cleanup of affected sites to be complete by 2021.

In February 1999, an official from Tampa's MacDill Air Force Base came to a California meeting with an environmental mystery. "We have two ditches that fill with water occasionally," explained Mark Canfield, MacDill's remedial project manager. "The bottom 8 inches of water are a 'safety yellow' color and the top 4 inches are clear." As he showed his colleagues photographs of the ditches, Canfield explained that the yellow material only appears periodically, and never affects nearby ditches. When he tested the water, Canfield found two alarming substances: thiodiglycolic acid and elemental sulfur. Both are breakdown elements of sulfur mustard agent, a chemical weapon that burns the skin and blisters the respiratory passages. Now banned by the Chemical Weapons Convention of 1993, sulfur mustard can cause respiratory cancer. Intense exposure can lead to death.

MacDill is not alone, of course, in chemical-weapons contamination. According to the Defense Department, bases across the nation started burying leaking and obsolete chemical warfare materiel during World War I, believing that to be the safest way to dispose of the poisons. While this was considered "an acceptable method of disposal," says one Army memo, the result was sometimes "incomplete and/or partial destruction." The Pentagon is now struggling with what to do with these toxic sites.

Covering 5,631 acres at the tip of the Interbay Peninsula, MacDill was used for chemical-weapons training starting in the 1940s. "Have you ever seen the videos where it's an old wooden building where they release chemical agent and [the soldiers] have a small amount of time to put their masks on? That's what it was," says Capt. Danny Cooper, a base spokesman. The agents, which Cooper says were not weapons grade, were stored in a "toxic gas yard" consisting of four "igloos" and seven other structures. Chemical materiel was buried in a base landfill. MacDill was also reported to be the site of a 500-pound bomb filled with mustard gas and buried near a mangrove swamp, though the actual bomb has never been located.

MacDill's chemical-weapons sites were located at the southernmost point of the base. According to the Air Force, the groundwater at these sites is now contaminated with arsenic, cyanide and lead. It also contains thiodiglycol, a sulfur mustard breakdown product; toluene, a lethal chemical that affects the nervous system and kidneys; and chloroacetic acid, which is used in the manufacture of thiodiglycolic acid and has been linked to intestinal perforation and depression of the central nervous system. MacDill's soils and sediment contain a similar toxic stew.

Numerous studies of potentially contaminated sites have been conducted at MacDill over the last two decades. Though contamination is generally thought to be minor, the relative risk at two sites mapped in 2002 and 2003 — the reputed bomb burial area and the toxic gas yard — is rated as "high." Human contact with the affected area is limited to "a very few people who work out there from day to day," says Capt. Cooper. The Pentagon expects to complete the cleanup by 2021.

By contrast, the Army Corps of Engineers has closed the books on another Bay area hot spot, the Hernando County Airport. Located 40 miles northeast of Tampa, the airport is the former home of the Brooksville Army Airfield, which was built as an auxiliary to MacDill in 1943 and used for chemical-weapons testing. Mustard bombs were loaded onto a plane at Brooksville and dropped in nearby woods (now Withlacoochee State Forest) to see how the agent pierced the canopy and spread. According to historical documents and media reports, 127 canisters of mustard agent were buried and burned at the Brooksville site. (One soldier shot at the burning mess, only to have it splash back at him.) A 55-gallon drum of thickened mustard agent was also disposed there. In 1963, tests found the soil contaminated with chemical agents, and according to the Army Corps of Engineers, "there exists no evidence ... that any significant cleanup had been performed."

All told, 1,000 pounds of chemical munitions might be buried at Brooksville. But when the Army Corps of Engineers excavated three areas last year, it found nothing. "They consider the airport to have no munitions left behind," says airport director Don Silvernell.

Army Corps spokesperson Cindy Foley warns, though, that chemical agents might well be present at Hernando County Airport. "The Corps was handicapped by a lack of information on how the Department of Defense used the property," she says. "There may be hazards that we just don't know. We never, ever consider a site absolutely safe."

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