U.S. Government Sprayed Very Toxic Chemicals on Native Reservation; Now People Are Suffering

There are places near the Gila River where the cottonwoods—otherwise pervasive in Southwest riverbeds—do not grow. Some members of the San Carlos Apache Tribe believe that is just one legacy of the dioxin-containing herbicide silvex, which was sprayed on the reservation in the 1960s and ’70s—at the same time that Agent Orange, a similar compound, was being dumped onto Vietnam’s countryside in an act of war.

The cottonwoods are not the only casualties of silvex. Entire families of San Carlos Apache basket weavers have passed on, victims of cancer. Those cancers, some tribal members believe, were caused by silvex when the basket weavers absorbed the noxious chemicals from the plants they stripped of bark with their teeth. Moreover, doctors and nurses who worked in the emergency room at the San Carlos hospital seem to have died of cancers at an unusually high rate, according to Charles Vargas, director of the Sovereign Apache Nation Chamber of Commerce.

Now, tribal members are seeking answers. With soil and water testing just beginning, the evidence is circumstantial. But those who see health impacts on San Carlos similar to those suffered by people exposed to Agent Orange are determined to prove the connection.

The links between dioxin, cancer and birth defects are solid, and Vargas and attorney Michael Paul Hill, another San Carlos Apache tribal member, are resolved to prove that these factors are influencing San Carlos Apache residents’ health. The circumstantial evidence is strong, and a nascent investigation is now under way. On January 18 Harry Allen, chief of the U.S. Environmental Protection Agency (EPA) Region 9 Emergency Response Section, visited San Carlos and took soil samples to check for silvex contamination at open dumps, two airstrips, the cottonwood-bereft stretch of the Gila River bank, and a field in an agricultural area.

Improperly stored barrels of everything from herbicides to paint and oil have been found on San Carlos in the past. In 1996, said Matt McReynolds, Assistant Attorney General for the tribe, an EPA incident report showed that seven barrels were removed from the basement of the Head Start office. Six of the barrels contained paint and lubricants; the seventh barrel contained an unidentified herbicide.

More barrels were stored under the old jail, said Vargas, and additional barrels have been found around the reservation, many exposed to the weather and corrosion, according to Hill.

In Arizona, the ostensible aim of the Gila River Phreatophyte Project—the silvex spraying program—was to destroy groundwater-guzzling vegetation in order to save water for the burgeoning city of Phoenix. The project area was a 15-mile stretch of the Gila River located on the San Carlos Apache Indian Reservation. One reason the reservation was chosen, according to the U.S. Geological Survey (USGS), was that the project could go forward without getting permissions and cooperation from multiple landowners. The tribe, with the approval of the Bureau of Indian Affairs (BIA), signed off on the spraying on May 28, 1962. Tribal leadership declined to comment for this story.

As early as the 1960s, labels on commercial silvex warned against reusing the containers, or even washing them out, with special warnings against contaminating irrigation ditches, water intended for domestic use, waterways and lakes. But that didn’t stop the BIA from allegedly giving empty silvex drums to the tribe’s Game and Fish Department, which handed them out to people on San Carlos to use as water barrels during ceremonies.

“People used them at the ceremonies, put the water in there, and then the water when it heats up gets contaminated; everybody’s contaminated,” said Hill.

At the same time the Forest Service was spraying silvex on the reservation in Arizona, the U.S. military was spraying Agent Orange over villages and crops in Vietnam to eliminate dense vegetation that provided cover for North Vietnamese and Viet Cong troops and to destroy their food sources. Between 1962 and 1971, the U.S. sprayed more than 3.5 million acres of jungle with 11.4 million gallons of defoliants.

Dioxin and Cancer

Dioxin is a known carcinogen. The U.S. Department of Veterans Affairs (VA) has conceded that many of the soldiers exposed to Agent Orange during the Vietnam Era developed serious illnesses, including leukemia and several other cancers; a disfiguring skin condition called chloracne; Type 2 diabetes; Hodgkin’s Diseases; heart disease, and Parkinson’s. The VA provides medical care for these Agent Orange–related diseases, and in 1991 the federal government authorized compensation for sick veterans.

In addition to leukemia and lymphomas, the VA lists prostate, respiratory cancers, multiple myeloma and soft-tissue sarcomas as attributable to exposure to Agent Orange and offers medical treatment and compensation to Vietnam-era vets for those diseases. As an indication of just how toxic Agent Orange was, the VA honors claims from military personnel who served “in Vietnam anytime between January 9, 1962, and May 7, 1975, including brief visits ashore or service aboard a ship that operated on the inland waterways of Vietnam.”

On San Carlos, the overall cancer rate was lower than the rate for the state as a whole in 1995-2000, but rose to virtually the same as the statewide rate by 2005-2009, meaning that cancer rates had increased an astounding 50 percent on San Carlos between 1995 and 2009. By comparison, cancer rates for the state as a whole decreased slightly over that same time period, according to the Arizona Department of Health Services.

From 2005–2009, the latest years for which numbers are available, residents of San Carlos suffered from kidney/renal cancer at more than 2.5 times the state rate and had seven times the state rate for multiple myeloma. Rates for childhood leukemia and colorectal cancer were slightly higher than the rates for the state as a whole. In 2010, the American Urological Association urged the VA to include kidney/renal cancer on the list of cancers presumably caused by Agent Orange.

Dioxin and Birth Defects

The VA acknowledges that one birth defect, spina bifuda, is associated with male veterans’ exposure to Agent Orange in Vietnam and provides compensation, medical care and vocational training for affected children. And the VA lists 18 birth defects presumed to be related to female veterans’ exposure to Agent Orange, ranging from cleft lip and palate to neural tube defects, congenital heart disease and hydrocephalus.

“A mother’s exposures can affect a pregnancy and the resulting offspring far more extensively than can paternal exposures,” the National Academies of Science says on its website.

In addition to direct exposure of a baby while in the womb, and on the breastfeeding newborn, there’s a chance for future generations to be affected, the National Academies said, because dioxin takes a long time to break down and thus accumulates in the body, the environment and the food chain. On top of that, exposure can cause birth defects in future generations because of epigenetic changes in an egg even before conception.

Indeed, Vargas said, one wing of the hospital on the San Carlos Apache Reservation serves children born with birth defects that he suspects may have been caused by exposure to dioxin.

In 1979, EPA issued an emergency order that immediately banned the use of silvex, based partly on studies showing that it caused reproductive and cancerous conditions in test animals, and partly on reports that women living in the vicinity of forests where silvex had been sprayed had suffered an unusually high incidence of miscarriages. Silvex, said the EPA, posed an “imminent hazard” to humans. The agency permanently banned silvex in 1985.

Dioxin Contamination

The reservation was not the only victim of dioxin spraying in Arizona. Five families from Globe sued Dow Chemical, the manufacturer of Kuron (another dioxin-containing herbicide), and the U.S. government for spraying that occurred in the Pinal Mountains of the Tonto National Forest near Globe from the mid- to late 1960s. Shoecraft v. Dow Chemical was settled out of court for an undisclosed sum in 1981.

The Globe lawsuit set the precedent for the class-action suit brought by Vietnam-era veterans against Dow Chemical and six other manufacturers of Agent Orange that resulted in a $180 million settlement in 1984. It was the largest settlement of its kind at the time, but not nearly enough to cover the medical bills of those harmed by Agent Orange.

Dioxin Persists in the Environment

Dioxin does not just go away naturally once it has been sprayed. It bonds to organic molecules and can persist in the environment for thousands of years. Further, it bioaccumulates, meaning that concentrations increase as the compound moves up the food chain.

“Dioxins are extremely persistent compounds and break down very slowly,” the EPA says on its website. “In fact, a large part of the current exposures to dioxins in the U.S. is due to releases that occurred decades ago.”

People can be exposed to dioxin by breathing it, ingesting it in food or water, or touching something that is contaminated. The EPA standard for the allowable amount of dioxin in drinking water is zero.

The tribe and the EPA in November signed a consent decree under which the tribe will clean up its drinking-water supplies, which were found to be contaminated with coliform bacteria, nitrates, arsenic, lead and copper. The consent decree did not include dioxin.

Jeff Porter, president the San Carlos Apache Tribal Utility Authority, said the tribe tests drinking water for dioxin once every three years and that the tests have always shown the level to be below that which would require remediation. But dioxin, noted Allen, binds to organic molecules in soil, so even if it were present in the environment, it would not be expected to turn up in water testing. In addition, McReynolds noted, only surface soil samples were collected during the EPA’s visit in January. If barrels of silvex had been improperly buried, he said, the barrels would have probably deteriorated by now and the chemicals would be underground, not on the surface.


Today, many of the orchards of fruit trees that had flourished for hundreds of years are gone, as are other food-producing crops—exactly the results one would expect on land sprayed with one of the most powerful defoliants known to science.

The current EPA survey is limited, Allen told ICMN. The EPA is looking only for places where silvex drums might have been stored improperly, not at sites where it was stored legally. And the agency is not investigating silvex contamination that might have resulted from the spraying program. The pervasiveness of the problem, combined with the impossibility of locating all the current sources of contamination, make for a potentially insurmountable challenge, McReynolds said.

“It’s like looking for a needle in a 1.8-million-acre haystack.”