The continuing search for more diseases caused by TCDD is not helping anyone


The herbicide known as agent orange was used for several years during the Vietnam War to defoliate forests to take cover away from enemy soldiers.

Agent orange and other herbicides were used from 1962 to 1971. The consequences of that practice promise to live on for many decades. 
Agent orange was a 50-50 mixture of 2,4-dichlorophenoxyacetic acid and 2,4,5-trichlorophenoxyacetic acid. Both of these compounds are considered

nontoxic to humans. The problem was that a contaminant of the 2,4,5-T was 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), which was discovered, while it

was being used, to be a very toxic chemical.

Complaints from Vietnam veterans about illnesses caused by their exposure to agent orange or TCDD began in the late 1970s. The issue quickly became a national issue, and by the mid-1980s, Congress passed legislation mandating studies, testing, and compensation to veterans who might have been exposed and harmed. Eventually, laws were passed requiring that compensation be paid to Vietnam veterans who were diagnosed with certain diseases associated with agent orange or TCDD. 
Unfortunately, no one could ever figure out just who was exposed to the herbicide. Records of aircraft sprayings and of troop positions did not match up. Essentially, the government had to compensate any veteran who served during herbicide spraying. 
Still, the issue did not go away; it just grew. Congress required continual reexamination of the veterans’ health for years. Now, more than 30 years after the spraying stopped, two major studies are ongoing in the U.S. The primary program is a continuing examination of the health of veterans who actually worked with agent orange, loading and spraying the chemical in Vietnam for Project Ranch Hand. These are the few people known to have been exposed to TCDD. 
The second is a literature review done by the Institute of Medicine to check the status of possible human health problems from agent orange. Four biannual reviews have been done so far; the latest was released last month. As in previous iterations, the panel found an illness that, it says, may be associated with exposure to agent orange. The IOM panel concluded that there is an association between agent orange exposure and chronic lymphocytic leukemia. The Department of Veterans Affairs has said this disease will be added to others for which veterans can get disability compensation. 
Most of the data linking any human disease with TCDD exposure come from occupational exposures during herbicide manufacture many years ago. An industrial accident in Seveso, Italy, also provides data. In both cases, exposure to TCDD was orders of magnitude greater than any Vietnam field soldier would have encountered. 
An early study by the Centers for Disease Control & Prevention found that the blood serum of veterans supposed to have been highly exposed to agent orange had the same range of TCDD concentrations as that of soldiers known to have never been exposed. The two groups could not be told apart. 
Why does the government continue to maintain that it can find concrete evidence of diseases in veterans caused by low levels of TCDD exposure after more than 30 years? If the men and women who served our country are becoming ill because of that service, they deserve to be taken care of. But we need to look beyond blaming just TCDD. Many of the people serving in Vietnam lived in a sea of chemicals, drugs, disease, insects, mold, and bacterial infections that could have had untold impacts on their future health. How can one relate the possible impacts of all these exposures to the clinical results of cellular changes caused by TCDD exposure found in a lab? 
And the impact of assuming TCDD to be the cause of many ailments goes beyond Vietnam veterans. TCDD, often just called dioxin, has become a favorite chemical used by many environmental activist organizations to scare the public. Despite the fact that TCDD concentrations in the soil and in people have been falling for more than 20 years, dioxin is still held up as a big chemical contamination issue. 
Part of the confusion over this compound comes from the Environmental Protection Agency, which, in its wisdom, lumped many chlorinated dioxins, furans, and polychlorinated biphenyls (PCBs) into the same group, saying that their structure made them likely to react similarly in the body. This group is simplistically called “dioxins” and is what most environmental groups now mean when they use the term without qualification. But much of the physiological impact of this group actually comes from the PCBs in the mix because they are of much higher concentrations than the actual dioxins, especially TCDD. 
Pressure on the government to do something for veterans with health problems found a scapegoat in TCDD. EPA has fumbled around with an assessment of dioxins’ toxicity for year and years, unable to come to clear conclusions. Industry, meanwhile, has eliminated most known sources of TCDD contamination, leading to the decline in environmental occurrence. 
After 30 years and numerous studies, the government will probably never have the kind of irrefutable and reliable data on agent orange and TCDD that it needs to prove that they caused illnesses in Vietnam veterans. Similarly, the government will probably never pin down what caused illnesses in Persian Gulf War veterans. Perhaps it is time for government researchers to shift the time and energy expended on agent orange to some of the other serious health problems in the world. And, as the U.S. faces future combat in Iraq, it is worthwhile remembering that in both training and combat, the armed forces face injuries, exposure to dangerous environments, and death.