In 1962, US commanders ordered a Marine named Don Heathcote to spray chemicals in the Okinawan jungle near his base as part of a series of biological warfare tests secretly carried out by the Pentagon during the Cold War.

Years later, Heathcote told a reporter that he did so without safety equipment and that while the herbicide killed the vegetation, it also damaged his health. “They diagnosed me with bronchitis and sinusitis connected to chemical exposure,” Heathcote said. Gerald Mohler, another Marine, was told to camp in the area, and said he later suffered from chronic breathing problems and neurological damage. “Were we Marines used as guinea pigs on Okinawa?” he asked the same reporter. “I think so.”

Jon Mitchell, the investigative reporter for the Okinawa Times who interviewed Heathcote and Mohler, has spent years documenting the Pentagon’s brazen use of the Pacific as a testing site and dumping ground for dangerous weapons. “Wherever the United States military goes, it contaminates and damages the environment and human health,” he told me.

He warns that the proposed US military expansion in the Asia-Pacific—its largest since the Vietnam War—will aggravate an environmental disaster caused by 75 years of American wars and intervention. “The Pacific islands have been militarized since World War II by the American military and are now the edge of the American Empire,” he said. “They suffered in the past and will inevitably suffer in the future.”

Mitchell’s recent book Poisoning the Pacific: The US Military’s Secret Dumping of Plutonium, Chemical Weapons, and Agent Orange, explores this largely unknown legacy. Based on hundreds of declassified US documents obtained under the Freedom of Information Act and interviews with US veterans and whistleblowers, it documents the Pentagon’s use, testing, and storage of chemical, nuclear, and other weapons of mass destruction (WMD) in the Pacific and the disastrous impact of its flawed handling and storage of such weapons.

Mitchell is originally from Wales and lives in Yokohama. At a time when think tanks are pressing for increased US military presence in the Pacific, his stories of the damage inflicted on Pacific islanders and US veterans should be required reading for every foreign policy wonk in Washington, D.C.

“For decades, US military operations have been contaminating the Pacific region with toxic substances, including plutonium, dioxin, and VX nerve agent,” Mitchell explains in his introduction. “Hundreds of thousands of service members, their families, and residents have been exposed—but the United States has hidden the damage and refused to help victims.”

The dangerous lurch toward military confrontation in Asia underscores Mitchell’s concerns. The US Indo-Pacific Command recently unveiled to Congress that it is seeking $27 billion in additional spending to station additional troops and weapons to counter what it says is a growing military threat from China.

The plans, which also draw on $4.6 billion appropriated by Congress for its Pacific Deterrence Initiative, include a precision strike missile network on the “island chain” running from Okinawa to the Philippines, the first US Marine base in the Pacific since the Korean War, a missile defense system on Guam, and a radar system on Palau in the Marshall Islands. The Pentagon is also seeking funds to “reorganize” the 27,000 Marines based in the Pacific region into small units in Guam, Japan, and Hawaii that can operate inside the range of Chinese rockets.

The harm that could follow from this expansion can be seen in Okinawa, the focus of much of Mitchell’s book. It h0uses 70 percent of the total number of US bases in Japan, where 50,000 American soldiers make up the Pentagon’s largest overseas contingent. Through his tenacious reporting, Mitchell has uncovered story after story about the use and misuse of WMDs on the island prefecture, which was occupied by the US military after the bloody battle for Okinawa in 1945 and handed back to Japan in 1972.

In 2011, Mitchell was the first reporter to interview US Air Force technicians on Okinawa in charge of the storage of nuclear weapons, which included over 1,200 warheads at Kadena and Naha Air Force Bases as well as at US Army ammunition dumps in Chibana and Henoko. He also broke stories about the US testing of biological weapons and its storage and transshipment of Agent Orange—the defoliant used over Vietnam—on Okinawa.

He wrote in his book that all the Air Force technicians he spoke to “agreed that the presence of nuclear weapons on Okinawa made it a key target in a preemptive or a retaliatory strike; one of the veterans described Okinawans as ‘human shields.’” Until that research, “nobody understood that Okinawa has a central part in US WMD testing, usage, and storage throughout the Pacific,” Mitchell told me.

His reporting extends beyond the Cold War. Mitchell uncovered the US military’s accidental use of depleted uranium rounds at an Okinawan live-fire range in 1995 and 1996, its dump of radioactive waste into sewers beneath US bases in mainland Japan in 2011, and hundreds of recent environmental accidents at US bases on Okinawa that were not reported to Japanese authorities.

His book also describes years of high-decibel noise pollution from the American jets flying near residential areas in Okinawa. Such long-term exposure is a serious health risk that can cause heart problems, disrupt sleep patterns, and damage cognitive skills in children. One Japanese university study estimated that noise from Kadena was responsible for an average of 10 deaths a year, with 17,000 people suffering from disturbed sleep.

The problem is particularly acute at the US Marine Corps Air Station at Futenma, which the United States promised to close in 1996 after massive protests from Okinawan citizens. This month, the Ryukyu Shinpo reported, a fleet of FA-18 combat jets held day and night trainings at the contested base. “Though a quarter of a century has passed“ since the agreement to shutter the base, the paper remarked, “the severity of the situation only continues to increase.”

The US military presence on Okinawa “is an environmental justice problem; that’s what the American people must understand,” Mitchell told me in clipped but angry tones. “I really hope my book helps people understand how badly the island has been contaminated, especially because so many American veterans are sick.” Through his research, he has documented claims from more than 250 veterans that Agent Orange was stored on Okinawa during the 1960s and ’70s.

His investigations have won him high praise in Japan. “Mitchell’s work has encouraged us to reject the ‘us versus them’ dichotomy and see commonality so we can help each other,” Hideki Yoshikawa, an anthropologist and activist who directs the Okinawa Environmental Justice Project, told me. “Getting to the truth is the critical first step in our fight.”

Earlier this month, the importance of US bases to America’s Pacific strategy was underscored when Japan’s Prime Minister Yoshihide Suga was the first foreign leader to meet with President Joe Biden at the White House. In a joint statement, the two leaders affirmed their “ironclad support” for the US-Japan military alliance and agreed that Japan would complete construction of a new US Marine air base at Henoko in northern Okinawa as the “only solution” to replace the unpopular Futenma facility.

But, as Mitchell points out, the US military is building the Henoko base, the scene of daily demonstrations, upon a pristine coral reef. “Their environment has been decimated by the American military,” he said.

The Pentagon, through US Forces Japan, denies most of Mitchell’s claims. “The statement that the U.S. does not clean up contaminants is simply false,” a USFJ public affairs officer wrote in a lengthy e-mail. “The GOJ [Government of Japan] has never indicated to the U.S. in any bilateral forum that the Okinawan environment has been ‘decimated.’” The American “response to environmental spills is some of the most aggressive in the world,” the PA officer added. “The health and safety of everyone in and around US installations is one of our top priorities and we take matters of environmental stewardship very seriously.”

USFJ also denied, as it has in the past, reports to Mitchell from US veterans about the storage of Agent Orange on Okinawa. In its response to me, the command referred to reports from Dr. Alvin Young, a military consultant who has spent years trying to convince the Pentagon and Department of Veterans Affair that herbicides did not make veterans sick. (A 2016 investigation by ProPublica about him was titled “Dr. Orange: The Secret Nemesis of Sick Vets.”)

A 2013 report from Young’s “independent consulting firm,” USFJ said, verified “the memories of US veterans regarding actual events of the period,” which included “the unloading of large 55 gallon drums from a ship and the spraying of pesticides in jungle operations” in Okinawa. But the investigation “found no record that validated any allegations that Herbicide Orange was ever shipped to or through, unloaded, used or buried on Okinawa.”

Despite USFJ’s claim that environmental protection is a “top priority of US leadership,” the Pentagon has tried to undercut Mitchell’s reporting. In 2016, he discovered through a FOIA request that the USMC Criminal Investigation Division was monitoring him. Around that time, certain websites wouldn’t open from Mitchell’s computer, and he soon found out that the US Air Force was blocking his ISP from accessing its home page. It was, he said, “an apparent attempt to hobble my ability to file FOIA requests online.”

Reporters Without Borders investigated and confirmed Mitchell’s claims and found that other Okinawan journalists were affected. After the organization reported the incidents, the USAF sites were restored to all users.

Through FOIA, Mitchell also documented that the State Department and the CIA have closely followed his reporting and speaking engagements in Japan. In his interview, he was unperturbed by the surveillance.

“For me, such tactics are a sign of success,” he told me. “They show my work is reaching the attention of the US authorities.” He was “particularly pleased” that the CIA had translated a Japanese TV report about his investigations into Agent Orange on Okinawa. “Now that they’re aware of these injustices, perhaps US policy-makers will be courageous enough to step in and right these wrongs.”

And there are many wrongs. One of the most riveting stories in his book concerns the US military’s storage of chemical weapons on Okinawa. The Pentagon, he writes, began placing these weapons during the Korean War and “incrementally” added more over decades. In 1961, according to declassified US Army reports, the Joint Chiefs of Staff authorized US commanders to expand the arsenal to include 13,000 VX land mines and almost 60,000 shells of sarin agent. The chemical weapons were part of an operation called “DOD Project 112 (Red Hat)” in which Heathcote was involved.

But with the island’s humid climate and salty air, the containers began to rust and leak. In July 1969, Americans at the Chibana depot were ordered to sandblast a large sarin bomb to prepare for its repainting when it sprung a leak; 23 service members and one civilian were hospitalized after they started to get short of breath. The leaks, multiple soldiers told Mitchell, were confirmed when rabbits placed at the storage site began to die from the poisonous air.

As Mitchell recounts, the US military did not make the Chibana accident public. But a reporter for The Wall Street Journal heard about it and reported the existence of the chemical weapons on Okinawa. The article caused a global furor and forced President Richard Nixon to renounce the first use of chemical and biological weapons. “That really terrified Okinawans,” he said. “They had no idea the US had 300,000 chemical weapons stored in Okinawa.” But the US government was mostly concerned with the bad publicity. CIA reports obtained by Mitchell suggested that Japanese leftists were exploiting the incident for “a good propaganda ride.”

Mitchell has also reported extensively on water pollution on US bases. During the 1960s, he said, the water near Kadena was so contaminated that “it literally could be set on fire.” In his book, he documents 650 environmental incidents between 1998 and 2016 at Kadena, largely caused by leaks of fuel and firefighting foam. “These incidents have ranged from small fuel leaks of only several liters that stayed on the base to large spills discharging tens of thousands of liters of fuel and raw sewage into local rivers,” he writes. “Military incompetence has repeatedly endangered local water.”

More recently, Mitchell documented severe water contamination in drinking wells around Yokota Air Base, the headquarters of US Forces Japan near Tokyo where American presidents and other senior US officials land when they visit Japan.

In 2000, officials from the Tokyo Metropolitan Government “found no evidence the pollutants came from inside the base.” But Mitchell argues that Japanese government reports carry little weight, because its officials are prohibited from entering US bases to carry out inspections. The problem, he contends, is the US-Japan Status of Forces Agreement signed in 1960. “Thanks to this agreement, the American military does not need to clean up contaminated land,” he said. “They do not need to allow Japanese officials to inspect the bases.” In contrast, in the United States “you can go to EPA web pages and find out what bases are contaminated with what.”

Asked about the SOFA clause that prevents Japanese officials from inspecting US bases, USFJ responded with a qualifier. While the “basic language” of SOFA has not changed “since its inception,” it said both the US and Japanese governments agree that the agreement “works well to serve the interests of the two countries.” In the end, it concluded, “the Commander of US Forces Japan is designated as the DoD Lead Environmental Component for Japan, and therefore will ensure US military operations are carried out in a responsible manner that will protect the environment now and for future generations.”

Statements like that, along with the lack of US press coverage, reflect “the disdain on the part of the American elite towards Okinawa,” Mitchell said. “Most American newspapers don’t report about these daily injustices to the people of Okinawa; they don’t report about the contamination; they don’t report about the weapons of mass destruction.”

To make the situation worse, “the American military has dismissed the testimony of servicemen, saying they are mistaken or were lying,” he told me. “So documents are vital.”

For that reason, he has donated most of his FOIA material for permanent display at universities and study centers in Okinawa, Hawaii, and Washington, D.C. “To criticize the military is one of the last remaining taboos of the American mass media,” he says. “The Okinawan people deserve better, so I’m committed to providing justice for them.”