Are ByFusion’s Plastic Building Blocks a Climate Solution?
The City of Tucson has partnered with ByFusion to build a facility at the city’s landfill that would convert plastic waste into large construction blocks known as ByBlocks. Supporters describe the project as a win-win—reducing plastic waste while producing building materials they say have a smaller carbon footprint than concrete. It sounds like the kind of innovation we’ve been waiting for. But when you look past the marketing, ByFusion’s plastic blocks raise more questions than they answer—and none of them point toward a sustainable future.
The core issue is simple: plastic is fossil fuel in solid form. Every piece of plastic that ends up in a ByBlock began its life as oil or gas extracted from the ground, refined in energy intensive petrochemical facilities, and polymerized into resin. Those upstream stages are where the vast majority of plastic’s climate pollution occurs. Producing 1 ton of plastic creates roughly 2–3 tons of CO₂-equivalent emissions from fossil fuel extraction, refining, cracking, and polymer manufacturing.
Yet ByFusion claims that its plastic blocks are “carbon neutral” and have a lower carbon footprint than concrete. These climate claims rely on a Life Cycle Assessment that uses the “cut off method,” a technical accounting choice that treats plastic waste as if it arrives at its manufacturing facility with zero environmental impact. All the upstream emissions that created the plastic in the first place are simply erased. That may work on paper, but it doesn’t work in the real world.
The atmosphere doesn’t care about accounting methods. The carbon footprint of plastic doesn’t vanish because a company decides not to count it. Repurposing plastic does not erase these emissions. It simply reshapes fossil fuel–based material into a new form. Before a plastic block even arrives at a construction site, it already carries the full carbon footprint of the virgin plastics from which it originated.
But the deeper problem is structural: ByFusion’s business model depends on a continuous supply of plastic while creating an illusion of progress for communities. It allows us to feel good about our waste without addressing the deeper system driving the problem: the overproduction and use of plastic, particularly single-use packaging and products.
Converting disposable plastics into construction blocks does very little to curb the ongoing extraction of fossil fuels used to make new plastic. In fact, programs like this risk normalizing the idea that plastic production can continue unchecked as long as we find “creative” ways to repurpose the waste. This is not a circular economy. It’s a detour that keeps us locked into the same fossil fuel pipeline that created the crisis.
If cities want real climate solutions, the path is clear. We must reduce plastic production at the source, support policies that phase out unnecessary plastics, scale up reuse and refill systems, and invest in building materials with genuinely low carbon footprints.
None of this is to say that diverting plastic from landfills is unimportant. But elected officials must distinguish between waste management and climate mitigation strategies. Plastic blocks may serve a niche role in local diversion programs, but they do not reduce plastic production, they do not eliminate upstream climate emissions, and do not move us toward the carbon-neutral future our communities deserve.