In 1965, fighter jets aboard the USS Forrestal—the first warship designed to carry such aircraft—completed an estimated 150 missions within the first four days of active duty. Then, on July 29, 1967, catastrophe struck. As flight crews prepared for another raid on targets in North Vietnam, a rocket measuring a little over 6-feet-long and five inches in diameter misfired, soaring straight into the side of a Skyhawk jet. The aircraft’s external fuel tank immediately ruptured, caught fire and ignited a conflagration that burned for hours. By the time the smoke cleared, 134 sailors had lost their lives.
The Forrestal fire is a cautionary tale and the inspiration for many contemporary safety protocols. A review of the fire revealed to safety inspectors the potent firefighting power of AFFF. Crewmen did everything they could think of to douse the fire, and some of the sailors happened upon the most efficient solution: foam. Other teams combatted the fire with seawater, which ultimately washed the foam off the deck and into the ocean. After the incident, the Navy instituted a number of new damage control improvements, which included the installation of AFFF to fight largescale fuel fires. AFFF became standard firefighting tools for government, commercial and private use, and we now know the utility of these foams come from a chemical cocktail laden with per- and polyfluoroalkyl substances (PFAS).
There was never really a reason to contain AFFF, because everyone thought it was similar to soap.
When many modern safety guidelines were originally instituted, little was known about PFAS, including their ability to linger in the waste stream and within our own bodies.
“There was never really a reason to contain AFFF, because everyone thought it was similar to soap,” said Jill Greene, CDM Smith principal and an expert in hazardous waste and hydrogeologic investigations. With little to no evidence of their hazardous potential, AFFF became ubiquitous. Today, they are a common cause of PFAS contamination throughout the world.
In the years since the Forrestal disaster, firefighting teams in the military and beyond established AFFF as a key fixture in emergency response units and for use in training scenarios. Simulating circumstances like those of the Forrestal explosion crews regularly discharged these foams as part of their training exercises. Safety experts did not realize the environmental implications of these PFAS-carrying fire suppressants as they migrated into soil and groundwater.
The use of AFFF was all but compulsory. Events like Forrestal inspired military safety personnel to mandate their use at highly combustible sites, a trend that spread to civilian assets like commercial airports. In addition to using them in to combat fires, and for simulations at dedicated firefighting training grounds, airports also started to install AFFF in fire suppression systems in their hangars.
While the Federal Aviation Administration (FAA) and Department of Defense (DoD) have started investigating alternative foams that do not contain PFAS, an efficient protocol for replacement has not yet been found. “The problem is decontamination and system compatibility,” Greene said. There is currently no standard practice for effectively removing PFAS compounds from pumps, tanks, trucks and hangar fire suppression systems. Individual components, if not the entire foam delivery system, may need to be replaced to be compatible with the new product. Furthermore, the latest health advisories for PFAS call for extremely low levels, measured in the parts-per-trillion. That means an increased likelihood of aggressive remediation of PFAS from discharges of AFFF to the environment, down to an almost non-detectable level.
There is currently no standard practice for effectively removing PFAS compounds from pumps, tanks, trucks and hangar fire suppression systems.
The dual nature of AFFF as life-saving firefighting foam and hazardous PFAS conduit is at the heart of current research to find alternatives that will save lives with the same efficacy and also protect the environment. FAA has taken early steps to stem the discharge of PFAS via AFFF transmission by providing guidance on testing foam dispensing equipment without discharging foam to the environment. But firefighters can’t train for large-scale disasters if they can’t actually spray the foam. And in the event of a real emergency, researchers are struggling with how to treat first responders and victims who come into contact with the foam. “How do you decontaminate people and equipment that have come in contact with AFFF?” said Greene. “No one has really had to do this before.” So far, water utilities have received the majority of the spotlight when it comes to PFAS coverage in the news. But many experts believe that airports are next. While researchers continue to study the behaviors of PFAS in the environment and search for new treatment solutions, here are best management practices that airports can take now to lower the risk of contamination:
Products: According to Greene, many airport workers may have never had a reason to step inside Aircraft Rescue and Fire Fighting stations or hangars. For planning purposes, she says it is important for team members to take a physical tour of the facilities and record all products that can potentially pollute the environment upon release. Develop a foam inventory and stock tracking system documenting the foam composition, brand, and manufacturer. “The first step of a prevention plan is knowing what you need to prevent,” Greene says. “Document what you have and get rid of anything expired or obsolete.
Use: Eliminate the use of AFFF products and other fluorinated “Class B foams for training and testing of foam systems and equipment” whenever possible. Provide containment, treatment, and proper disposal of foam solution. Avoid direct release to the environment to the greatest possible extent.
Fire Suppression Systems: Inspect and maintain fire suppression systems and evaluate the possibilities for accidental activation. When it comes to emergency preparedness, more is better. Greene recommends redundant activation measures like adding a flame detection camera in addition to existing heat sensors. Consider a subsurface storage containment system to help control the spread of dangerous pollutants in the event of an actual fire. “If the foam is dispersed, there would be a diversion valve to guide the material into the floor drains and to a contained unit underground,” said Greene.
Emergency Response Plans: In addition to incorporating extra safeguards into a suppressant system, it is also critical that airports design a comprehensive response plan. In the unfortunate event of a real emergency, airport management will need to assemble a crisis support team, which can include firefighters and emergency personnel, airport Operations staff, environmental staff, legal experts and and public relations professionals.
Stay tuned to Breaking Down PFASfor the latest research into fire suppressant substitutes, PFAS containment and remediation technologies, including initiatives currently underway at CDM Smith laboratories.