By Philip Paff
In Australia, a great deal of attention is on the past use of aqueous film forming foam (AFFF) containing perfluorinated compounds (PFCs) such as perfluoro-octanoic acid (PFOA) and perfluoro-octane sulfonate (PFOS) by municipal, industrial, and defense force agencies.
The use and effectiveness of these firefighting foams produced from the 1960s to the early 2000s was good; however, the ongoing development of fuel, environmental, and personnel contamination issues saw a reduction and eventual phasing out of AFFF in the early 2000s. AFFF was intended to extinguish hydrocarbon-based flammable and combustible liquid fires (Class B). Firefighter contamination may have occurred during training or periodic vehicle maintenance. You may have seen AFFF use during foam training or demonstrations such as a simulated boat fire or aircraft crash.
These foam concentrates were mostly water and included a mixture of components such as solvents, biocides, corrosion inhibitors, and foaming agents. The added fluorinated surfactants based on PFOA and PFOS displayed the desirable properties of simultaneously being water and fat repellent. This property assisted with foam solution spread, thereby forming a thin layer over the fuel and creating a barrier that minimized evaporation and reduced heat flux from flame to the fuel, which, in turn, canceled out the feedback loop and extinguished the fire.
|1 ARFF training exercises from the early 2000s. (Photo by Jed Crosby.)|
What are fluorine-based AFFFs and why the concern?
The emerging issue with many of these foams is the potential health hazard posed by the inclusion of fluorinated surfactants – mainly the two compounds of PFOA and PFOS mentioned earlier. Typically, fluorinated foams contained 0.5 to 1.5 percent PFOS and trace quantities of PFOA. Studies have shown that PFOS is a toxic pollutant that remains in the environment indefinitely, with research estimating time frames of 30 to 90 years. PFCs are bio-accumulative, meaning that they can also build up in biological tissue.
PFCs have many applications, from coatings on nonstick cookware to an additive in concrete, and are very pervasive in our environment. Because of widespread applications, PFCs now contaminate every ecosystem on the planet. Being bio-accumulative ensures they enter the food chain; therefore, levels increase as they are consumed by animals such as fish and cattle, progressively being concentrated in the food chain before eventually ending up in humans.
These two materials are environmentally persistent, with a long half-life (it takes approximately 42 years to rid 50 percent of PFOS and 91 years to rid 50 percent of PFOA from the environment). PFOS is classified as a persistent organic pollutant, while PFOA is classified as a Class 2B carcinogen (it is possibly carcinogenic based on limited available evidence).
There are two key areas of concern with these AFFFs containing these compounds: environmental impacts and health impacts.
Concerning the health impact, it is important to recognize that the body cannot metabolize these chemicals. Studies show it can take between four and eight years for the body to rid itself of half of any PFOS/PFOA exposure. There is some evidence reported in literature of animal studies of changes in the liver, kidney, thyroid, pancreas, and hormone production. Some studies on rats have also indicated a potential to promote cancer; however, it is not clear if these results have human health implications. There is much uncertainty about human health impacts, and it is not clear they cause adverse health impacts, but based on current evidence the potential for adverse health outcomes cannot be excluded.
For firefighters, the main route of entry is usually by the respiratory system, especially at incidents. Firefighters may also handle open containers of concentrated foams at the firehouse when topping off the apparatus tank during scheduled maintenance. Do not ignore the potential for incidental ingestion as a possible route. Exposure times vary according to activities, but consider your own experiences.
|2 ARFF training exercises from the early 2000s. (Photo by Jed Crosby.)|
Even though production and use have ceased, the presence of fluorinated foams is still felt. Within Australia, 18 defense installations are being investigated for contamination, which may affect up to 1,200 households. Residents of some affected areas have been advised by health authorities not to consume eggs, milk, or fish produced within the affected areas. In a localized study of one location, residents tested returned levels of PFC contamination up to 40 times the estimated national average. Closer to home, the U.S. military is currently assessing contamination levels of 664 sites, many of which were used for crash and fire training.
A study of a group of Australian firefighters in 2014 indicated PFC levels in ranges six to 10 times higher than that of the Australian population. Considering that the major manufacturer as the primary source of this product ceased production in 2002, these levels are still quite high.
Regulations in North America, Canada, Europe, and Australia have banned the ongoing production of foams containing PFOS. Ongoing materials development now provides modern foams without PFCs that represent a higher level of effectiveness when used on modern fuels, particularly ethanol-based blends that are more readily biodegradable.
What is not gauged in many departments is the existence of legacy stocks of fluorinated foam concentrates.
Because of the ability of PFCs to persist in the environment, a solution is difficult at best.
Luckily, research indicates levels in the general population are declining. Beginning in 2000, this has been driven by regulatory responses globally, whereby organizations such as the U.S. Environmental Protection Agency have restricted production with an intent of phasing out entirely.
Note that our use of self-contained breathing apparatus (SCBA) to protect from the obvious products of combustion such as smoke is well entrenched. It is in our best interest to be proactive in SCBA use to also protect us from exposure to other environmental elements, such as the use of foam solution.
|3 Example of a bulk drum of PFOA/PFOA foam product. (Photo by author.)|
Legacy contamination: our people. Many firefighters who may have been exposed to firefighting foam products containing PFCs are now senior members of our departments. A large number of departments currently already apply presumptive laws on many cancers that are implicated with our work exposure. Consider formulating a plan to research and include health implications associated with exposure to foam products.
Legacy contamination: the environment. Environmentally, fire departments around the world should account for and remove all PFOS foam concentrates. Additionally, there is a need to consider and plan for the potential emerging issue of legacy contamination of the environment. This consideration may take the form of departmental (or third-party) testing of the ground and runoff collection pits or drafting wells around training sites for evidence of PFOS/PFOA and microbiological activity. Remediation work to correct a site will come at substantial cost and may involve the mass removal of many thousands of tons of affected topsoil. This may not always be economically viable, let alone practical. The alternative, as extreme as it may appear, is to abandon an entire site and its surrounds, as has been the case in Australia.
We exist to help the community. It is up to us to maintain that approach even if the issue was born of us.
Brambilla G, D’Hollander W, Oliaei F, Stahl T, Weber R, 2015, “Pathways and factors for food safety and food security at PFOS contaminated sites within a problem based learning approach,” Chemosphere, vol. 129, June, pp. 192-202.
Cheremisinoff, N, 2016, Perfluorinated chemicals (PFCs): contaminants of concern, Scrivener Publishing, Beverly.
Filipovica, M, Woldegiorgisb, A, Norströmc, K, Bibic, M, Lindbergb, M, Österåsb, A, 2014, “Historical usage of aqueous film forming foam: A case study of the widespread distribution of perfluoroalkyl acids from a military airport to groundwater, lakes, soils and fish,” Chemosphere, vol. 129, June, pp. 39-45.
Lloyd-Smith, M, Senjen, R 2016, “The persistence and toxicity of perfluorinated compounds in Australia” viewed January 29, 2016, http://www.ntn.org.au/resources.
Olsen, G, Burris J, Ehresman, D, Froehlich J, Seaca,t A, Butenhoff, J, Zobe,l L, 2007, “Half-life of serum elimination of perfluorooctanesulfonate, perfluorohexanesulfonate, and perfluorooctanoate in retired fluorochemical production workers,” Environmental Health Perspectives, vol. 115, no. 9, pp. 1298-1305.
United Nations Environment Programme, 2004, “Annexe B-Stockholm Convention” viewed December 17, 2016, http://chm.pops.int/TheConvention/ThePOPs/ListingofPOPs.
United States Environmental Protection Agency, “Drinking water health advisories for PFOA and PFOS,” viewed January 26, 2016, www.epa.gov/ground-water-and-drinking-water/drinking-water-health-advisories-pfoa-and-pfos.
Wilson, M, 2007, “Fluorotelomer based foams: are they safe for continued use?” Industrial Fire World, vol. 25, summer.
PHILIP PAFF, AFSM MIFireE CFO, is a 22-year fire service veteran and a rescue station officer with Queensland Fire and Rescue (Australia). He is also a member of Australia Taskforce 1 USAR, having deployed nationally and internationally. A senior rescue instructor and shift officer, Paff has a bachelor’s degree in emergency service operations and is a recipient of the Australian Fire Service Medal.