Why Changing From C8 to C6 Foam Didn’t Improve Firefighter Safety

two firefighters handle a hose dispensing firefighting foam

The chemical backbones of C8 versus C6 fire foams are not so different that choosing one over the other drastically improved firefighting safety. C8, otherwise known as ‘legacy’ aqueous film-forming foam (AFFF), was used by the fire industry to extinguish Class B fires for more than 40 years until its ‘safer’ cousin became the dominant fire suppressant from 2016 until today. Switching away from C8 was a must because its harmful effects weren’t up for debate, but what too many firefighters are now realizing is that C6 wasn’t a substitute without repercussions.

Is C6 Fire Foam Safe for Firefighters?

Despite popular belief, C6 isn’t a safe alternative for firefighters to use to fight Class B fires, because like C8, this foam is also hazardous to users’ health, makes a negative environmental impact, and its suppressant capabilities aren’t improved from the original C8 formulation. Switching to C6 and using false terms to describe this alternative foam, like safe, non-toxic, and not accumulative, caused many to incorrectly conclude that this substitute did not pose the same health hazards as past concentrations of AFFF. 

Missteps in Developing and Changing Fire Foam 

The original catalog of AFFF (C8) concentrates used synthetic PFAS (per- and polyfluoroalkyl substances) as the active ingredients. These are now known as ‘forever chemicals’ due to their resistance to degradation in nature, wildlife, and human tissue, but research on these was lacking at the time of AFFF development. 

The PFAS were engineered using one of two manufacturing processes—electrochemical fluorination (ECF) or fluorotelomerization (FT). This brand of C8 AFFF was mass-produced and widely used from the 1970s until its phase-out in the early 2000s. The foam has since been labeled as PBT (persistent, bioaccumulative, and toxic), and its byproducts—PFOS/PFOA—are two hazardous forever chemicals known to cause cancer and other adverse health problems.

The legacy AFFF containing FT-derived PFAS remained in production for 15 years longer than the ECF-derived foam; its sale wasn’t discontinued until 2016. This formula contained a balance of short- and long-chain PFAS that was mistaken as a safer alternative. The concentrate wasn’t taken off the market out of precaution, though. This legacy AFFF remained for sale until precursor chemicals in its makeup were found to degrade to hazardous PFAS byproducts. While chemical engineers employed by the manufacturers likely knew a few molecules’ difference wasn’t enough to improve the safety of AFFF, the companies profiting from these formulations didn’t raise any red flags. Due to this negligence, thousands of firefighters who responded to Class B fires between 1970 and the early 2000s have been diagnosed with devastating diseases.

When the Environmental Protection Agency (EPA) launched its PFOA Stewardship Program, AFFF manufacturers were encouraged to reformulate the firefighting foams to stop the production of long-chain PFAS. While the updated formulations seemed to meet the request, PFAS (short-chain versus long-chain) remained in C6 foams. As more information about the effects of AFFF exposure was revealed, the fire industry shifted away from using C8, known to be especially persistent, bioaccumulative, and toxic, and made C6 foam the dominant suppressant despite its having the same active ingredients—PFAS. 

These C6 concentrates are referred to as ‘modern’ AFFF and they’re still in use today. After learning the similarities between C6 and C8 composition, would you answer “yes,” when questioned whether C6 fire foam is safe for firefighters? The safety of C6 must be questioned for these four reasons:

1. C8 and C6 Fire Foam Are Chemically Similar

Modern AFFF, C6, is thought to be a safer version of firefighting foam because its chemical makeup differs from legacy C8, but the similarities between these two compounds shouldn’t be ignored. 

The base of all versions of aqueous film-forming foam is PFAS, which are formed when a carbon atom bonds with fluorine. This strong chemical bond makes the foam blanket such a reliable, strong suppressant—and it’s also what makes AFFF a health hazard. Though there are fewer bonded atoms in C6 versus C8, the compound retains its primary chemical characteristic: persistence.

2. C6 Doesn’t Offer Improved Suppressant Performance

Nor did moving from C8 to C6 improve safety on the front lines of fires. As fire suppressants, both concentrates create an aqueous barrier between the fuel source and the foam blanket to extinguish the fire, and neither is marketed as faster or more effective than the other. If there’s any argument between the two, one could say that C8, which contains more bonded carbon atoms, offers greater resistance against the fuel layer. Suggesting that C6 is a safer alternative for firefighting doesn’t hold any ground when considering the suppressant performance. 

3. The Safety of Short-Chain vs. Long-Chain PFAS Was Incorrect

The presence of short-chain versus long-chain PFAS is the reason C6 was lauded as the next-best C8, offering safety and effective suppression. Research on short-chain PFAS has a long way to go to catch up to the library of knowledge on long-chain PFAS. This knowledge gap left many to assume short-chain PFAS were synonymous with safety, but this misconception about AFFF led firefighters astray. The problem with considering only the carbon count of a molecule at the time of synthesis is that it fails to account for chemical breakdowns, degradation, or anomalies from contamination. Since C6 firefighting foams have become the primary suppressant for Class B fires, research has found that short-chain PFAS contain precursors that inevitably degrade to hazardous chemicals similar to long-chain PFAS.

4. Firefighters Took Safety Claims Seriously

Research has shown that moving from C8 to C6 did nothing to eliminate firefighters’ contact with PFAS, and designating this foam as safe instead of safer led to relaxed precautions and improper handling, putting countless firefighters in harm’s way. The impact of AFFF on the environment and public health continued with C6, a fluorosurfactant disguised as a safe, eco-friendly alternative. Several factors led firefighters to believe using C6 versus C8 was a smart choice.

Why Did We Switch From C8 to C6?

Fire brigades and military installations switched from using C8 to C6 AFFF ostensibly for safety reasons, namely, avoiding long-chain PFAS. Firefighting foam with short-chain compounds was marketed as less dangerous, less toxic, and less environmentally hazardous, but these terms were misinterpreted, leading many to believe C6 was safe, non-toxic, and eco-friendly.

If the life cycle of AFFF development and replacement seems familiar, it is. The industry is again changing its suppressant, this time from AFFF to fluorine-free alternatives. While no one will argue that this switch needs to be made, it is understandable that firefighters have reservations when seeing manufacturers’ technology superseding research once again. It’s time that first responders and fire crews find advocates—AFFF legal help—to speak up against manufacturers responsible for years of negligent fire suppressant production.