Halloween hoopla hides a frightening real-life experiment that secretly used Marshall Islanders to study the effects of nuclear fallout on human subjects for 40 years and remains controversial still.

Today’s fog of gore oozing from Halloween advertisements and attractions obscures the all-too-true experiment codenamed by the U.S. government in 1954 as Project 4.1. It provides an eerie, contemporary counterpoint as the U.S. pivots to the Asia-Pacific region and continues using a Marshall island as bulls-eye for its missile defense tests.

Project 4.1 was spotlighted in Honolulu last week in a documentary titled "Nuclear Savage." The film gives voice to bitter Marshallese who claim U.S. scientists secretly used them as guinea pigs when they became the world’s first victims of radioactive fallout without enduring a bomb’s holocaust. The U.S. denies their allegations.

On March 1, 1954, hundreds of Marshallese were dusted with snowflake-like radioactive fallout when hydrogen bomb Bravo exploded near their ancestral homelands. Bravo, 1,000 times more powerful than the A-bomb that devastated Hiroshima, was laced with plutonium, one of the planet’s deadliest substances with a radioactive existence of half a million years that may be hazardous to humans for at least half that time.

The fallout touched off a historic chain reaction of events. Islanders began vomiting, developing burns and losing hair. U.S. officials told the world the islanders were fine. About 400 were evacuated from their lethal hotspots on Rongelap and Utrik atolls.

In Washington, Project 4.1 began to unfold. About March 4, E.P. Cronkite recalls, he was instructed to report at once to the Navy Surgeon General’s Office, where he met officials in the government’s top medical program. By March 8 Cronkite and 25 other medical personnel arrived in the Marshall Islands, where he was handed a "letter of instruction" referring to Project 4.1. Titled the "Study of Response of Human Beings Exposed to Significant Beta and Gamma Radiation Due to Fallout from High Yield Weapons," it remained classified for 40 years.

Six weeks after Bravo, on April 14, Project 4.1 officials recommended a "life long" study of the exposed islanders — and they began to be studied regularly for decades without their informed consent, without benefit to them and without receiving medical care.

After three years, U.S. officials assured the Rongelapese that their atoll was safe and returned them to their radioactive homeland. Utrik Islanders were returned home shortly after Bravo.

A decade after Bravo, for the first time the U.S. disclosed that five of 82 fallout-dusted Rongelapese had died. Other Marshallese suffered abnormal thyroid growths, miscarriages, birth defects, mental and physical retardation.

Many lost their lives or their loved ones, as exemplified by John Anjain, Rongelap’s mayor in 1954. Because of fallout, he and four family members were operated on for thyroid tumors. His wife’s tumor killed her. His son died from leukemia.

For 28 years, the Rongelapese lived on their contaminated atoll. Then, in 1985, discounting U.S. assurances, Rongelapese persuaded Greenpeace to move them again. Today, afraid to return to a radioactive environment, they languish on another atoll, despite U.S. pressures to resettle.

In 1983, the U.S. relinquished its United Nations-sanctioned trusteeship over the Pacific Islands, entered into a Compact of Free Association that made the Republic of Marshall Islands a sovereign nation with American military perquisites and set up a $150 million trust fund that partially compensated some radiation-injured Marshallese. But that trust fund is now depleted.

Last month, the U.S. was called upon to do more. It should remedy and compensate Marshallese for its nuclear weapons testing that has caused "immediate and lasting effects" on their human rights, according to a report presented to the U.N. Human Rights Council in mid-September in Geneva, Switzerland.

Meanwhile, in a wealthy Washington suburb, Project 4.1 has morphed into a Halloween haunted house attraction called "The Warehouse: Project 4.1." Disregarding decades of Marshallese sacrifices long hidden from the public, college-age entrepreneurs promise thrill-seekers in Rockville, Maryland, "a realistic, bloody, bio-hazardous warehouse filled with attacking zombies, decaying bodies, (and) vicious military men."

The attraction is a "sad example of gross insensitivity," Marshallese official Tony deBrum has declared. He asks, "Is this a joke?"