If you’re reading this on a smartphone or laptop, you can thank lithium-ion batteries. Their high energy density, long lifespan, and fast charging capabilities have revolutionized portable power. Electric cars, e-bikes, smartphones, laptops, earbuds, and more use them.
Unfortunately, these batteries also pose a major fire hazard. In New York City alone, 277 fires were started by lithium-ion batteries last year. According to the Federal Aviation Administration, lithium-ion battery fire incidents occur on U.S. flights weekly or more.
In an attempt to mitigate this serious danger, manufacturers are adding chemical flame retardants to the plastic cases surrounding lithium-ion batteries. Is it making a difference? In a Viewpoint published last week in Environmental Science & Technology, scientists from the University of Toronto and the Green Science Policy Institute explain that adding flame retardants to the plastic around these batteries has no proven fire-safety or other benefit. Additionally, the types of flame retardants widely used in battery enclosures are linked to cancer and other health harms, and if the enclosures enter the global recycling stream, the harmful flame retardants can end up in inappropriate places like children’s toys, food containers, and utensils.
Flame Retardants In Battery Enclosures Have No Proven Benefit
As the usage of lithium-ion batteries expands, flammability standards that are met with chemical flame retardants are being hastily adopted for a variety of plastic battery enclosures. However, there is no publicly available research demonstrating that this use of flame retardants curbs battery fires under real-world conditions. Flame retardants in plastics cannot impact the highly energetic fires from a lithium-ion battery in thermal runaway.
“Trying to stop thermal runaway fires by adding flame retardants to plastic is like adding a screen door to a submarine. It’s a futile effort against an overwhelming force,” according to distinguished fire scientist Dr. Vyto Babrauskas.
Further, when plastics burn, flame retardants can create additional smoke, soot, and toxic gases, which are major causes of fire deaths. They can also produce dioxins and furans, which can contribute to firefighter cancer.
Flame Retardants In Battery Enclosures are Linked to Health Harm
The flame retardants widely used for this purpose are organohalogen and organophosphate chemicals which have been linked to cancer as well as neurological, reproductive, and immune system harm. Young children and pregnant women are the most vulnerable.
The flame retardant chemicals can migrate from plastic cases of many products—from earbuds to e-bikes—into air, dust, water, people, animals, and end up in our food supply. If recycled at the end of their useful life, these products can contaminate the recycling stream and impede the circular economy. This contributes to the contamination of products made from recycled plastic—like the infamous black plastic spatula, sushi trays, and children’s toys. Disposal by burning or landfilling leads to toxic emissions and can be harmful to the global environment and human health, especially in low-wealth countries.
Other Flammability Standards Have Turned Out To Be Ineffective
This would not be the first time that the use of flame retardants to meet flammability standards has resulted in health harm without proven fire-safety benefits. For example, an unfortunate long-time California furniture flammability standard did not reduce fire deaths. Meanwhile, the flame retardant most often used to meet that standard was linked to the loss of three to five IQ points among U.S. children and a fourfold increase in the risk of dying from cancer. Since that standard was updated a decade ago to be met without flame retardants, furniture fires have remained minimal or even decreased.
The best solution for both public health and fire safety is to prevent battery fires from occurring in the first place. Strategies like improving battery management systems and stopping the use of faulty batteries can prevent dangerous thermal runaway fires. This would save lives both from fires as well as from cancer and the many other health harms linked to flame retardants.
