Forest Wildfires and Residential Fire Toxins

After the collapse of the World Trade Center, the full impact of the toxic clouds of burned debris has reared its ugly head. While the focus remains on the Twin Tower’s Toxins, the country is on fire!

Forest fires, residential fires, and building component fires remain on the backburner of public concern. Insurance companies, fire clean-up crews, and construction workers are generally focused on the immediate problems at hand while ignoring the potential impact of toxins in the aftermath of extensive fire damage.

Forest fires can leave a wake of human tragedy that extends well beyond the obvious forest and residential damage. That tragedy is the release of toxins that have no immediate affect on the health of those exposed, therefore no immediate concern or precautions. Yet, several years later, the story book may change. This was the case of asbestos exposure and, although unconfirmed (presently under litigation), the Twin Tower’s toxins.

Now, the Texas Bastrop Wildfire that occurred in September 2011 resulted in the damage of 34,000 acres of land and 1,400 homes, and once again, the main concern is to restore people’s homes. The concern for that which you can not see or that which has no immediate health effects has not been an overriding consideration. That said, let’s look at the potential toxic releases in a discussion regarding: (1) forest fires; and (2) residential fires.

First, forest fires result in the release of dioxins, one of the most toxic substances known to man. Dioxins are a group of compounds, the most toxic of which is 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD).  2,3,7,8-TCDD is one of the most carcinogenic compounds known man. If one ascribes a toxicity level of 1 to 2,3,7,8-TCDD, the other dioxins range in relative toxicity from 0.1 to 0.0001 (as determined by the World Health Organization).[1]

Second, residential fires are not without the release of toxins.  During a fire, thermal decomposition of building materials, light bulbs, appliances, furniture, and cleaning/maintenance products can result in a medley of toxins—some of which will settle in the dust, soot and debris while other more volatile (e.g., gaseous) will dissipate into the atmosphere.

In the Twin Towers, the most offensive toxin generated from the building materials was asbestos. The source was asbestos-containing thermal insulation. Very few older residences had asbestos-containing thermal insulation, but asbestos shingles and asbestos siding were common in houses up to 1978. The more recent, modern homes are unlikely to have had asbestos construction materials. Public awareness of asbestos health hazards and the phased-in ban on asbestos building materials in residential construction have resulted in its limited use, and in newly constructed homes, asbestos exposure concerns following a fire are minimal. There are, so to speak, bigger fish to fry.

Burned copper electrical wiring, plumbing, and mechanical air handling coils will result in airborne copper fumes which will ultimately settle in the dust, soot and debris in the aftermath of a fire. Many paints have toxic heavy metal components as well. For instance, lead-containing paints which were banned in 1978 in residences were in common use in high quality exterior paints, and there is lead in car batteries. Arsenic has been used as a pigment, wood preservative (e.g., Wolmanized® treated lumber), and anti-fouling agent (e.g., paint on boats). Mercury, cadmium, and chromium were used as pigments and preservatives.

Some woods are treated with toxic pentachlorophenol (PCP) which will thermally decompose to unknown gases and is suspect of containing dioxins. Toxic chlordane and other household pesticides are also likely to decompose to gaseous toxics and likely to dissipate into the atmosphere, or the gases may be trapped and retained within the carbon soot.

Roof and sheathing particleboard glues may thermally decompose to release gaseous formaldehyde, phenol, and unpredictable toxins resulting from the thermal decomposition of the building components. Whereas the gases are likely to dissipate, heavy metals are more likely to settle in the dust, soot and debris.

Even as newer building materials are entering the marketplace (especially in green energy construction), thermal decomposition of some of the newer, synthetic products may have a few toxic surprises (e.g., recycled compressed and glued woods). And the list goes on.

There are unintended consequences connected with energy-efficient fluorescent light bulbs. All things containing mercury will, not might, result environmental contamination. Normally, fluorescent light bulbs are recycled, but this becomes impossible when broken or damaged in a fire. Fluorescent light bulbs have 1.5 to 35 milligrams of mercury each. Most homes use fluorescent lights in the garage, kitchen, and workshop. Beyond that modern homeowners that can afford it purchase energy-efficient lights to replace the incandescent lights.

Other sources of mercury include, but are not limited to, thermostats (for heating and AC temperature controls), TV and computer LCD screens, and some older gas-fired appliances. Mercury was further used in anti-mold paints, button batteries, neon lights (as much as 100 to 500 milligrams of mercury each), UV tanning lamps, and some pesticides.

Many of the older light ballasts and outdoor electrical transformers had polychlorinated biphenyls which when they burn (or explode) produce dioxins and furans. Furans are a relative of dioxins. Dioxins are also a byproduct of burned vinyl tiles, many plastics, and foam cushions.[2]

Plastic upholstery and polyvinyl chloride can result in gaseous vinyl chloride and semi-volatile polycyclic aromatic hydrocarbons (PAH). Some of the PAHs are suspect human carcinogens. After a fire, the gaseous and volatile organics dissipate into the atmosphere while semi-volatile organics tend to settle within the soot, debris, and on surfaces.  There are over 50 toxins listed and screened as environmental contaminants of concern. Some of those on the list are phthalates (e.g., plasticizers), pyridine (e.g., cigarette smoke), and naphthalene (e.g., moth balls).

The thermal decomposition of household cleaning and maintenance products, as well as automotive maintenance products and stored paints, can serve up a mixture of unknowns. The possibilities are endless!