ENVIRONMENTAL PROTECTION

The CIA Lost a Nuclear Device Filled With Plutonium on Nanda Devi

And it’s still out there

Nanda Devi — Wikipedia

On the summit of Nanda Devi, India’s second-highest peak, the CIA abandoned a nuclear-powered surveillance device six decades ago. ASNAP-19C generator containing 5 kg of deadly plutonium (1/3 of a nuclear bomb) lies buried beneath the ice in one of the most remote locations on earth. Now, due to global warming and the retreat of the ice, it threatens to contaminate India’s vast Ganges River basin.

This is the story of an undercover CIA / India spy mission 60 years ago — a tale of reckless ambition that stirred fears of environmental catastrophe for the nation of India.

Screenshot — Washington Post Archives

The Spark — China’s Nuclear Awakening

In October 1964, China detonated its first atomic bomb. With limited intelligence on China’s remote test sites in Xinjiang, the CIA scrambled for ways to monitor missile developments. Satellites were unreliable at the time, so an unconventional idea emerged: plant a remote sensing station high in the Himalayas to intercept signals from Chinese launches.

The ideal location was Nanda Devi, India’s second-highest mountain at 25,645 feet (7,816 meters), offering line-of-sight into China while remaining on Indian territory. Following India’s 1962 border war defeat to China, New Delhi and India’s Intelligence Bureau cooperated quietly with the CIA.

The device was powered by a SNAP-19C generator, which used plutonium-238 for heat-to-electricity conversion, with some sources noting plutonium-239 as well.

Indian Military Expedition To Nanda Kot — The Himalayan Club

The Climbers and the Ascent

Elite mountaineers were recruited for the covert operation, code-named Operation Hat. Veterans from the American 1963 Everest expedition joined forces with Indian counterparts led by Captain Manmohan Singh Kohli, a naval officer and accomplished Everest summiteer.

Disguised as a scientific expedition, the team — including Sherpas who used the device’s warmth to sleep unknowingly — hauled the heavy generator, antennas, and transceivers up the slopes in 1965.

They reached a high altitude, but in October, a brutal blizzard hit. Survival became paramount, forcing tough decisions.

Twin peaks of Nanda Devi from advance base camp — The Himalayan Club

Americans warnings about the risks of leaving plutonium near a glacier feeding the Ganges were overruled. Manmohan Kohli ordered the equipment cached on a secure ledge, with plans to return after the monsoon.

Nanda Devi High Camp 4(1964 expedition) — The Himalayan Club

The Vanishing

When a recovery team returned in 1966, the ledge had been swept away by an avalanche. Only scraps remained. Subsequent searches in 1967 and 1968, equipped with detectors, yielded nothing.

Nanda Devi High Camp 5 (1964 expedition) — The Himalayan Club

Experts say the Plutonium fueled device likely melted deep into the glacier due to its own heat. A replacement was successfully placed on nearby Nanda Kot (and later removed).

The CIA downplayed the Nanda Devi loss internally and never acknowledged it publicly. Details emerged years later through declassifications and participant accounts.

The Ganges River — Parker Hilton

Living Under the Shadow

Nanda Devi’s glaciers feed the Rishi Ganga, which joins the Ganges — a sacred river sustaining hundreds of millions. Plutonium is highly toxic; ingested or inhaled, it causes cancer. A 1979 Indian investigation found no contamination and deemed risks “negligibly small,” yet fears persist, amplified by climate change accelerating glacial melt and fueling disasters like the 2021 Uttarakhand floods.

Climbers like Jim McCarthy, who later battled cancer he attributed to exposure, carry regret.

“You can’t leave plutonium by a glacier feeding into the Ganges! Do you know how many people depend on the Ganges?”

he shouted in a recent interview with the New York Times.

“The whole thing is a sad chapter in my life,” Kohli reflected before his death in 2023.

Today, Indian politicians and locals demand answers and recovery. As one farmer asked:

“If people can go to the moon, why can’t they find out what happened to this device?”

Sixty years on, this botched Cold War operation underscores how the hidden costs of espionage can endanger ecosystems and communities long after the spies have gone.

Thanks to a recent New York Times article, it has been newly brought to the world’s attention and new efforts may be made to locate the device and/or compensate those affected.

Recent lawsuits related to Plutonium exposure:

• Veteran Sickened by Plutonium brings Nationwide Class Action. Military members exposed to plutonium in the Palomares incident, where 2 USAF planes collided, and an explosion showered nuclear bomb waste over a large swath of Spain.
• Rocky Flats — a former nuclear weapons facility operated by Dow Chemical Co. and Rockwell International Corp., dispersed plutonium and contaminated 30 square miles of property around the facility in Colorado. A court awarded $990 million to thousands of property owners whose homes were exposed to plutonium.
• Savannah River Plutonium Pit environmental lawsuit — Nonprofit public interest groups reached an historic settlement agreement with the Department of Energy in January 2025 to half production at Savannah River until a nation-wide programmatic environmental impact statement (PEIS) has been completed.

The US government has made no public statements on this incident in decades, including as of late 2025. The most recent official US acknowledgment dates back to the late 1970s, when press reports (starting with a 1978 Outside magazine article) forced disclosures.

In 1978, the US State Department confirmed key details in internal communications (later declassified), stating: “Recent press stories reporting that the CIA placed two nuclear-powered monitoring devices in the Himalayas in the 1960’s to monitor Chinese nuclear activity are correct in major respects. One of these devices was lost in an avalanche and never functioned; the second did function for several years and was later removed.”