Some four years ago, a family in the small city of Layton, located in northern Utah, wanted to get rid of the lawn-destroying voles living in their yard. They called a local pest control company. And the applicator -- as the resulting criminal investigation revealed -- took a total warfare approach, seeding the lawn with more than a pound of pellets containing the fumigant aluminum phosphide.
Within a few days, their two youngest daughters -- one four years old, one just over a year in age -- were dead. The tidy little home seemed suddenly so dangerous that the National Guard was called in to do the toxicity readings. They found -- perhaps not surprisingly -- dismaying levels of phosphine gas which had been released by the pellets as they interacted with moisture in the air.
Phosphine gas is notoriously lethal (enough so that it was featured recently in a murderous episode of Breaking Bad). The pure gas is colorless and odorless so it carries no warning sign. It's a fast, systematic, and corrosive killer; it "denatures" and breaksdown a range of enzymes and proteins inside the body, including the ones responsible for moving oxygen through the body, and severely damages the heart. And, as a follow up investigation noted, has no known antidote.
Within a few months after the Utah deaths, the U.S. Environmental Protection Agency tightened the restrictions on the use of aluminum phosphide. The longstanding buffer zone of 15 feet from a residential building was expanded to a far more cautious distance of 100 feet. Only professional operators could buy the compound and they had to follow careful procedures to use it (in Canada, it takes six months to be certified in its use).
People who admired its low-cost efficiency -- aluminum phosphide came into use in the 1950s and it is both cheap and destructive to pests from from voles to bedbugs -- protested the restrictions, insisting that the pesticide was getting a bad rap. But the agency didn't budge. "Phosphine fumigants are poisons and must be kept away from where our children live," one administrator said flatly.
No argument from me. The chemistry of aluminum phosphide is so potent that studies show that people who accidentally inhale dust from the pellets, or swallow some of the material, can produce phosphine gas internally as the compound reacts with moisture in the body or even stomach acids. And it's this rather appalling picture -- and the issue of careful regulation -- that leads us now to a still mysterious series of tourist deaths in Southeast Asia.
I first wrote about these deaths in 2012, after two young sisters from Quebec died in their hotel on Thailand's resort island of Ko Phi Phi Don. What caught my attention first was the improbable list of possible causes offered by Thai authorities, everything from poisonous mushrooms to cocktails laced with the mosquito repellent DEET. It rapidly became obvious they were among a surprising number of young women who had suffered undiagnosed poisoning deaths in Southeast Asia, some in the Phi Phi islands, others elsewhere in Thailand, and still others in Vietnam. My emphasis was on the unsolved nature of those deaths and the sorrow and frustration of their families.
Now a team of investigative journalists from Canada have published a report suggesting that the young sisters -- Audrey and Noémi Bélanger -- appear to have been killed by aluminum phosphide/phosphine gas exposure. The experts they consulted say the bodies showed all the signs of this kind of acute poisoning, including bluing of the fingernails and toenails, which is a classic symptom of the kind of rapid oxygen-deprivation produced by this poison. The report, which also appears on the Canadian Broadcasting Company's Fifth Estate program, cites evidence that some of the other travelers, such as a Norwegian woman who also died in the Phi Phi Islands, showed similar symptoms.
Interestingly enough I heard recently from a source in Thailand that aluminum phosphide is also suspected in the Vietnam deaths. In both cases, the theory is that the pesticide was used in hotels to kill off bedbugs, which are resistant to many other toxins. Thai authorities have responded that this pesticide is not allowed or used in hotels but the Canadian reporters heard otherwise from some of the hotel operators. In fact, aluminum phosphide poisoning is a known problem across much of Asia and the Middle East. The compound is sold widely as both a grain fumigant and as a handy pesticide. It's not a surprise that it turns up far too often as a cause of death, accidental, suicidal, and occasionally homicidal. One study of poisonings in northwest India, for instance, cited it was the number one cause of poisoning deaths in that region.
And if you go to this Wikipedia entry on aluminum phosphide poisoning, you will find that almost all the citations derive from research done in India and other Asian countries. And there are more beyond that, such as this one from Iran and this one, interestingly enough, from a scientist from Thailand. Public health authorities in Saudi Arabia recently collaborated on a dark-themed film about the aluminum phosphide/phosphine gas problem there, hoping that public awareness would reduce the risks. The YouTube film, "Phosphine," has racked up more than 3.5 million views.
"Public awareness must increase in the community and society must not wait until the authorities arrive, they must act quickly in order to save their lives," a Saudi epidemiologist tells the viewers in the film. My take on that is just a little different. First, the authorities need -- and this is equally true in the United States -- to do a better job in monitoring -- and when needed, yes, restricting -- our use of very poisonous compounds. It's unreasonable to expect everyone to have awareness of the full range of toxic chemical compounds.
And, yes, we also should do a better job of raising community awareness, of helping people figure out what chemical compounds are memorably dangerous. We need to teach everyone kid-glove respect for the compounds that matter. So that when someone on a lovely little resort island suggests using aluminum phosphide to fumigate the rooms, or when a pest exterminator decides to go for an overdose, there's always someone to remember that this is a very, very bad idea.
And then the sisters from Canada get their chance to dance on the beach before they go home. And the little girls in Utah get their chance to grow up.
