Until it was shut down by the Environmental Protection Agency (EPA), Fort McClellan Army base in Anniston, Alabama, among its many functions, served as a site for the Army’s Chemical, Biological, Radiological and Nuclear Corps. But one function which remained constant throughout its tenure was the housing and disposal of chemical weapons. In 1999, the EPA closed the base, labeling it a hazardous site due to chemical waste which had leached into the ground, contaminating the soil and water supply.

Unfortunately for residents and soldiers who were already exposed to toxic chemicals at the base, Fort McClellan wasn’t the only toxic dumping ground in the town of Anniston. For decades, Monsanto, the agrochemical company responsible for manufacturing herbicide and genetically modified organisms (GMOs) found in food, had been contaminating the area with toxins, including polychlorinated biphenyls, or PCBs.  In 2003, residents successfully sued chemical giant, however, veterans who were based at Fort McClellan were prevented from joining this lawsuit.

A bill introduced in 2013 called the Fort McClellan Health Act sought to create a registry for veterans stationed at the base to help them get coverage for health issues stemming from their exposure to toxins, and open up disability payments. However, the bill was referred to a committee where it has yet to advance.

PCBs are man-made chemicals that were manufactured in the town of Anniston from 1929 until mid-1972. The contamination infiltrated bodies of water, land and air.

“Most of the PCB contamination all around, especially on the east coast, comes from [Anniston,]” Dr. David Carpenter, director of the Institute for Health and the Environment at the University of Albany, told FoxNews.com. “The fact is, people living anywhere near the plant have significantly higher levels [of PCB] in their bodies than the average person in the U.S.”

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PCB has been linked to a higher risk of a range of diseases, including hypertension, heart disease, diabetes, and reduced IQ and suppressed immune system function in children. The World Health Organization (WHO) has labeled it as a known human carcinogen.

There is increasing understanding of the mechanisms of PCB in the body, but the chemical is known to cause changes in over 300 of genes. Genes regulate the synthesis of proteins, and PCB causes some to increase production and others to decrease. At this level, genes control every bodily function, making it unsurprising that PCB has such a wide-ranging effect, Carpenter, who has served as an expert witness in legal cases against Monsanto, said.

“We certainly know genes are central for causing cancer, but also they regulate things like blood pressure and diabetes,” he said. “It’s hard to say this and that [specific] gene is responsible for [disease-causing] changes, but it comes down to the fact that [changes in genes] is almost certainly the mechanism why so many different human health functions are altered.”

Carpenter noted that, for those working at Ft. McClellan, they were also exposed to other potentially hazardous chemicals.

“When you allow for the fact that you have exposure to chemicals changing genes, plus potent nerve gases and all kinds of chemicals, certain mixtures aren’t good for you and may, in fact, add to toxicity one would get if they were only exposed to chemicals from one source,” he said.

Because its molecular structure resists being broken down, PCB in the environment is very difficult to eliminate. To destroy it, the contaminated soil would have to be incinerated, which is costly. Now, PCB-contaminated soil is being stored in landfills that are lined on the bottom and the top to prevent leakage into the soil and groundwater.

“It’s just going to sit there forever,” Carpenter said.

In the human body, enyzmes in the liver break down PCB to some extent, but it’s difficult to remove because it is fat soluble. According to Carpenter, eating contaminated fish is one of the biggest root causes for PCB exposure in Anniston.

“If you ate contaminated fish for dinner last night, you’ll have half of those PCBs in your body 10 years from now, “ Carpenter said.  “It’s impossible to clean the human body very quickly.”

For both women and men, PCB has especially long-lasting effects through disruption of the endocrine system.  After high exposure, young girls have been shown to reach puberty earlier. A pregnant woman can transfer PCBs to her children during gestation or through breastfeeding. For men, there is strong evidence that exposure in utero increases the risk of birth defects of the male reproductive system. Men also experience reductions in testosterone, and sperm count may be lower. Carpenter is currently pursuing a study on whether exposure before birth changes the susceptibility for obesity.

Another issue that is still being understood, Carpenter noted, are the epigenetic changes caused by PCBs. These changes in genes— that are not mutations— can transmit characteristics over two to three generations.

Men tend to have higher concentrations of PCBs than women, as women pass along the body burden to their children. Additionally, because eating animal fat is a major root of exposure, the fact that men tend to eat more than women increases their likelihood of having a higher exposure, Carpenter said.

While food has been a well-documented means of PCB exposure, one current area of research is exposure through the air.  There are 209 possible types of PCBs that had been thought to have the same health effects, but whether food or air exposure have similar effects has come into question.

“I don’t think there is a clear answer, although I’m pretty convinced they’re not all the exact same, and the health effects are not the exact same,” Carpenter said. “They just need a lot more study.”

Though a single molecule of PCB does not cause disease, there is no health benefit to the chemical that currently affects the entire population.

“Everybody in the U.S. is going to be affected by these compounds to some degree,” Carpenter said. “It’s not to say everybody has identified disease, but these things disrupt normal physiological function and at certain concentrations spill over to what we identify as disease.”