Friday morning’s fire at the George Town Landfill could threaten the health of anyone exposed to the thick, oily smoke billowing from the site, and could cost as much as US$1 million to extinguish, according to an expert on landfill fires.
A burning dump, frequently caused by spontaneous combustion in the wake of the intense heat created by decomposition of biological materials, releases a wide range of pollutants, including carbon monoxide, aldehydes (e.g. formaldehyde), acrolein, benzo (a) pyrene, hydrogen bromide, hydrogen chloride, hydrogen cyanide, hydrogen fluroride, nitrogen oxides, phenol, sulfur dioxides, dioxins and furans, and have both short and long-term health effects.
Most immediately, lesions of the skin, called chloracne can occur, while peripheral neuropathy and liver enzyme induction are also possible, although frequently reversible.
Other possible disorders include cardiovascular and respiratory disease, and boosted rates of diabetes and gastrointestinal cancer, said Patrick Foss-Smith, a U.K.-based global expert on dump fires.
Dioxins themselves are highly toxic and can cause reproductive and developmental problems, damage the immune system, interfere with hormones and cause cancer, he said.
Air pollution from dump fires threatens the elderly and anyone with respiratory and cardiac illnesses, may increase infant mortality, cause low birth weight in babies, the onset of childhood asthma, coughs, wheezing, chest tightness, shortness of breath, burning in eyes, nose and throat, dizziness, weakness, confusion, nausea and disorientation.
Generally, “the toxins are called ‘pop’s – persistent organic pollutants,” said Mr. Foss-Smith, “and you cannot let these things continue to burn.”
Particularly noxious, he said, are subterranean fires, much like Friday’s landfill conflagration, which the surrounding waste filters, meaning “the hot growing particulate matter percolates upwards” and into the atmosphere.
The emissions rarely produce an odor, Mr. Foss-Smith said, making them difficult to detect, although “sometimes it smells like a barbecue or an old oil refinery.”
Like coal-seam or peat fires, subterranean landfill blazes cannot be extinguished with water, although depriving them of oxygen often works.
More than 8,000 dump fires in U.S. each year
Annually, 8,300 landfill fires in the U.S. cause US$8 million in damage, while the U.K. has nearly 300 fires per year. Most fires burn refuse, vehicles, small on-site structures and surrounding brush and grass. Discarded tires, particularly prominent at the George Town site, burn with a per-pound heat output higher than most coal and produce large amounts of oil and thick dark smoke containing carbon monoxide, sulfur dioxide and products of butadiene and styrene. Such fires are extremely difficult to contain, much less extinguish, and can flare up again weeks and even months later.
“Deep-seated landfill fires do not ‘burn’ in the accepted sense,” said Mr. Foss-Smith. “These fires are a form of combustion known as pyrolysis, where the thermal reaction takes place in an oxygen-starved environment.
“The combusting material is consumed very slowly and at low temperatures. As the waste is heated, it begins to devolatalize,” which he likened to the vapor produced by a candle when it is blown out.
These “volatiles” can be converted into carbon monoxide, dioxin, often from PVCs, hydrogen sulfide from gypsum drywall board or simply re-deposited on the surface of the cold waste that has not yet been burned.
Mr. Foss-Smith’s point is that “once devolatalization is complete, the remaining fuel, in the form of fixed carbon can remain hot, under starved oxygen conditions, for years.
“They can carry on burning until it burns itself out,” he says – which can take as long as 14 years.
Eventually the landfill site turns to ash and will collapse in on itself, causing a sinkhole.
“The cost to extinguish a fire is a minimum of US$1 million,” he said, “because you need such a lot of equipment: multiple fire engines, hydraulic excavators. It’s dangerous.”
The particulate carbon from burning tires can be so small that “it can be airborne for two weeks,” and the smaller of the two particle sizes, 1.5 microns and 10 microns, “passes from the lungs into the blood stream.”
In a recent article in the U.S.-based monthly Waste Management World, Mr. Foss-Smith offers some advice for landfill managers, particularly appropriate in the aftermath of Cayman’s Friday landfill fire: “Recent research reveals a worrying lack of understanding by licensing authorities, of their role in fire-risk reduction together with a lack of landfill fire competency by site operators and the emergency services.
“Landfill operators need to be vigilant for hot deposits during the working life of landfills,” he said. “Knowing their clients and their arisings, enforcing good working practices, maintaining adequate out-of-hours security and being especially vigilant during the ‘hot’ aerobic phases of the landfill lifecycle will all help to reduce the likelihood of a fire.”