Yellow rain
Samples of the supposed chemical agent that were supplied to a group of independent scientists turned out to be honeybee feces, suggesting that the "yellow rain" was due to mass defecation of digested pollen grains from large swarms of bees.
[3] Although the majority of the scientific literature on this topic now regards the hypothesis that yellow rain was a Soviet chemical weapon as disproved,[4][5] the U.S. government has not retracted its allegations,[6] arguing that the issue has not been fully resolved.
[7] A 1997 textbook produced by the U.S. Army Medical Department asserted that over ten thousand people were killed in attacks using chemical weapons in Laos, Cambodia and Afghanistan.
[2] The descriptions of the attacks were diverse and included air-dropped canisters and sprays, booby traps, artillery shells, rockets and grenades that produced droplets of liquid, dust, powders, smoke or "insect-like" materials of a yellow, red, green, white or brown color.
[2] Secretary of State Alexander Haig announced in September 1981 that: The Soviet Union described these accusations as a "big lie" and said that the US government used chemical weapons during the Vietnam War and supplied them to Afghan rebels and Salvadoran troops.
[16][17] The US government responded to these findings by arguing that the pollen was added deliberately, in order to make a substance that could be easily inhaled and "ensure the retention of toxins in the human body".
[14] After the honeybee hypothesis was made public, a literature search turned up an earlier Chinese paper[20] on the phenomenon of yellow droppings in Jiangsu Province in September 1976.
[21]: 46 Analyses of putative "yellow rain" samples by the British, French and Swedish governments confirmed the presence of pollen and failed to find any trace of mycotoxins.
[18][22] Toxicology studies questioned the reliability of reports stating that mycotoxins had been detected in alleged victims up to two months after exposure, since these compounds are unstable in the body and are cleared from the blood in just a few hours.
[13] An autopsy on a Khmer Rouge fighter named Chan Mann, a victim of a putative yellow rain attack in 1982, turned up traces of mycotoxins, but also aflatoxin, Blackwater fever, and malaria.
[21]: 46 Australian military scientist Rod Barton visited Thailand in 1984, and discovered that Thai villagers were blaming yellow rain for a variety of ailments, including scabies.
An American doctor in Bangkok explained that the United States had been taking a special interest in yellow rain, and was providing medical care to alleged victims.
For instance, a 1992 review published in Politics and the Life Sciences described the idea of yellow rain as a biological agent as conclusively disproved and called for an assessment by the US government of the mistakes made in this episode, stating that "the present approach of sweeping the matter under the rug and hoping people will forget about it could be counterproductive.
They argued that presence of pollen in yellow rain samples is best explained by the idea that "during biological warfare attacks, dispersed trichothecenes landed in pollen-containing areas.
This event revived memories of what New Scientist described as "cold war paranoia", and the article noted that the Wall Street Journal had covered these 1980s yellow rain allegations in particular detail.
[40] The Iraqis appear to have investigated trichothecene mycotoxins in 1990, but only purified a total of 20 ml of the agent from fungal cultures and did not manage to scale up the purification or produce any weapons containing these compounds.
The episode prompted a backlash among some listeners, who criticized Robert Krulwich for insensitivity, racism, and their disregard for Yang's personal and professional experience with the region in question.
[49] American Hmong poet Mai Der Vang published Yellow Rain (Graywolf Press, 2021) to critical acclaim and was a 2022 Finalist for the Pulitzer Prize in Poetry.
