Aqueous Film Forming Foam (AFFF) is a synthetic foam primarily used for suppressing fires, specifically Class B fires which involve flammable or combustible liquids. Its key ingredients include hydrocarbon surfactants, fluorocarbon surfactants, and solvents. These chemicals are blended together to form a foam concentrate, which when mixed with water, creates a stable foam blanket that cools the fire and separates the flame from the fuel source.

AFFF was initially developed in the 1960s for the purpose of rapidly extinguishing high-hazard petroleum and aviation fires, such as those found at oil refineries, airports, and military bases. It is efficient because it has the ability to spread across the surface of a liquid fire, cutting off the oxygen supply and consequently extinguishing the flames.

Various products in the marketplace contain or utilize AFFF. One such product category is firefighting equipment, which includes handheld extinguishers, sprinkler systems, and foam proportioning systems, all used in commercial, residential, and industrial settings. Other products include emergency response vehicles and certain types of fire suppression systems found in marine vessels and aircraft.

In terms of how humans might come into contact with AFFF, it largely depends on the situation and their professional involvement. Firefighters, military personnel, and those working in industries like aviation, oil, and gas are most likely to come into contact with AFFF during their daily operations, training exercises, or in the event of an emergency such as a fire.

The general population may also be exposed to AFFF, albeit less frequently, in scenarios such as accidental discharges of fire suppression systems or via contaminated water sources. AFFF can infiltrate soil and groundwater, particularly in areas close to where it's frequently used like airports, military bases, or fire training facilities. Hence, people living or working in proximity to these areas can be exposed through ingestion or dermal contact with contaminated water or soil.

Concerns have arisen over the years about the health effects of exposure to AFFF, especially those that contain certain types of per- and polyfluoroalkyl substances (PFAS). PFAS, often referred to as "forever chemicals" due to their environmental persistence, are linked to a variety of adverse health effects.

Studies suggest that long-term exposure to these substances may lead to an increased risk of various health conditions. For instance, kidney and testicular cancers, thyroid disease, high cholesterol, pregnancy-induced hypertension, and ulcerative colitis have been associated with PFAS exposure. Additionally, it may impact the body's immune response and interfere with the body's natural hormones.

In children and infants, exposure can potentially lead to developmental issues, decreased immune response to vaccinations, and an increase in cholesterol levels. Furthermore, PFAS are capable of crossing the placental barrier, meaning that they can potentially affect the health of an unborn child.

It's important to note that the level and duration of exposure, as well as individual health factors, play a significant role in determining the health impact of these substances. However, given the potential risks associated with exposure to PFAS, there is an increasing push to find safer alternatives to AFFF.

The health risks associated with AFFF exposure have led to greater scrutiny and regulation of its use, with many industries and countries moving towards PFAS-free alternatives. For individuals who may be exposed to AFFF or contaminated water, it is important to limit contact and seek regular health check-ups to detect any potential health issues early on. The situation with AFFF underlines the broader importance of careful assessment and management of industrial products to protect human and environmental health.