AFFF is a foam concentrate product which, when sprayed on a flammable liquid fire, forms a thin aqueous film at the fuel/air interface suppressing the combustion reaction. It may contain fluorinated or non-fluorinated surfactants. Some fluorinated surfactants are straight chain and some a mixture of straight and branched chains.

AFFF foams are generally intended to extinguish flammable and combustible liquids. These foam concentrates are mostly water and include a mixture of components including: solvents, biocides, corrosion inhibitors and foaming agents. Historically, many of these foams included fluorinated surfactants.

Perfluorooctanoic acid (PFOA) and perfluoroctane sulfonate (PFOS) are fluorinated surfactants. PFOA and PFOS are part of a broader group of chemicals called per- and poly-fluoroalkyl substances (PFAS). Typically, these foams contained 0.5% to 1.5% PFOS and trace quantities of PFOA. Another common component is perfluorohexane sulfonate (PFHxS). Some fluorinated foams have components called fluorotelomers that transform into PFOA.

PFAS have many applications, from non-scratch cookware and hydraulic fluids to surface coatings (including within concrete) and water repellent coatings in clothing.

In Queensland, AFFF foams are found at mine sites, ships, airports, defence facilities and facilities that use or store large volumes of flammable and combustible liquids such as refineries.

Prior to 2003, we purchased AFFF foams along with other types of foam such as protein-based foams. Since that time, we have not purchased AFFF.

However, this does not mean we have not applied legacy stocks, or stocks directly supplied by a site during a fire, or at a significant spillage of a flammable/combustible liquid. They may have also been used during training or during vehicle maintenance. They may have been used during foam application demonstrations, such as a firefighting demonstration of a tugboat. Historically, emergency use has been infrequent and involved low volumes.

AFFF foams are not classified as dangerous goods.

PFOS is classified as a persistent organic pollutant, whilst PFOA is not currently classified as a persistent organic pollutant. Health authorities consider PFHxS similar to PFOS and so add these two PFAS chemicals together when assessing risks. PFOA is also classified as a Class 2B carcinogen, and that means it is possibly carcinogenic based on limited evidence. There are two key concerns with these AFFF foams: environmental impacts and health impacts.

These two materials are environmentally persistent. It takes about 42 years to get rid of 50% of PFOS, and 91 years to get rid of 50% of PFOA from the environment. They readily bio-accumulate in the food chain.

The body cannot easily get rid of these chemicals, and it takes between 4-8 years to remove half of any PFOS/PFOA in our system. There is some evidence reported that animals exhibit changes in the liver, thyroid, pancreas and hormones. Some studies on rats have indicated some 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. However, on current evidence, the potential for adverse health outcomes cannot be excluded.

The primary exposure to PFAS (including PFOS and PFOA), is via ingestion (food and water) through the food chain. Other exposures may include dust containing PFAS and contact with our clothing. As a result, all humans will have small amounts of PFOS/PFOA in their body.

When considering occupational exposures, the following is assessed:

• source/s of exposure - such as the material, its concentration and its form
• the pathway - how is exposure occurring?
• duration of that exposure
• the body - such as how does it get in, leave and what will it do inside.

Typically, for a firefighter the main entry route is usually the respiratory system, especially at incidents. Historically, firefighters have handled containers of concentrated foams at stations or on an appliance, and may have had contact with finishing foam during this application. For example: cleaning, checking or servicing vehicles. Whilst the respiratory pathway cannot be ignored, skin seems a likely pathway to consider. Exposure times may vary according to the activities.

It is important to minimise any opportunities for exposure, and adopt suitable measures to prevent contact and protect your respiratory system and skin. After a fire, always shower at the station upon your return.