The hidden carcinogens inside your walls: why your framing material is a health decision

I started this company because of what I learned about indoor air

I spent 20 years at Qualcomm working with materials at the micron scale. When I started looking into residential construction, I expected to find outdated building methods. What I found instead was a public health problem hiding in plain sight.

The EPA has documented that indoor air can be 2 to 5 times more polluted than outdoor air, and occasionally up to 10 times worse. The World Health Organization attributes 3.8 million premature deaths annually to indoor air pollution. And we spend roughly 90% of our lives indoors.

People tend to blame candles, cleaning products, and cooking. Those matter. But the largest, most persistent source of contamination in a home is the structure itself. Researchers at the University of Michigan found at least 55 chemicals of concern embedded in standard building materials, many present at concentrations exceeding health maximums by factors of 1,000 or more.

That is what pushed me to build Core X Frame. Not just a faster framing system. A fundamentally less toxic one.

The problem is deeper than paint and carpet

When families try to build a healthy home, they usually start with the visible stuff: low-VOC paint, natural fiber rugs, organic cotton furniture. Those help. But the most dangerous chemicals are not on the surface. They are structurally embedded inside the walls, under the floors, and above the ceilings. You cannot access them without demolishing the house.

Wood framing is the default for residential construction. It seems natural, even wholesome. But wood is a decaying organic material. To make it last 50 years inside a wall cavity, the lumber industry treats it with heavy-metal preservatives, synthetic adhesives, and chemical flame retardants. The result is that the skeleton of your home becomes a continuous source of indoor contamination.

What raw wood actually emits

Even untreated solid wood is not chemically inert. Freshly milled softwood produces measurable quantities of formaldehyde. Pine, oak, spruce, and aspen emit volatile organic compounds (VOCs) and very volatile organic compounds (VVOCs) from their natural resins, terpenes, and fatty acids.

Research using advanced PTR-TOF-MS analysis has shown that standard gas chromatography significantly underestimates wood emissions. The characteristic "pine scent" comes from terpenes like alpha-pinene, 3-carene, and limonene. They smell clean, but when they react with indoor ozone they form ultrafine particulates that irritate the lungs.

Oak and hardwoods emit acetaldehyde, classified by the IARC as a Group 2B possible carcinogen, along with acetic acid, which triggers asthma-like symptoms in people with allergies or compromised lung function. These are not trace amounts. In a tightly sealed, energy-efficient home, they accumulate.

Engineered wood is worse

Solid lumber is expensive and increasingly scarce. The construction industry has shifted heavily toward engineered wood products: oriented strand board (OSB), plywood, medium-density fiberboard (MDF), and particleboard. These materials are made by bonding wood chips and fibers with synthetic adhesives under industrial pressure.

The adhesives are the problem. The most common is urea-formaldehyde (UF), a thermosetting resin that is chemically unstable. It degrades under mild humidity and continuously releases formaldehyde gas into the living space. Engineered panels bonded with UF emit formaldehyde at rates up to 100 times higher than natural lumber.

Formaldehyde is not a borderline concern. It is a known human carcinogen with strong epidemiological links to leukemia and chronic respiratory disease.

The emission curve is also counterintuitive. Research published in PMC found that while initial terpene and solvent emissions from engineered panels decrease after manufacturing, toxic aldehyde emissions (including formaldehyde) can actually increase over time due to surface auto-oxidation. You cannot just "air out" a new home and assume the problem is solved.

Mold: the hazard that wood guarantees

Wood absorbs moisture. It is hygroscopic by nature. In any home that experiences a plumbing leak, a roof failure, high humidity, or even condensation from an HVAC system, the wood framing inside the walls will get wet. When it does, mold grows. Not might grow. Will grow.

The EPA confirms that mold spores trigger allergic rhinitis, dermatitis, conjunctivitis, and acute asthma attacks. But the real danger comes from toxigenic molds that produce mycotoxins.

Stachybotrys chartarum (black mold) produces macrocyclic trichothecenes, compounds that inhibit protein synthesis and trigger cellular death in lung tissue. During a documented outbreak in Cleveland between 1993 and 1998, pulmonary hemorrhage was identified in 138 infants living in mold-infested, water-damaged homes. 12 of those infants died.

Beyond spores and mycotoxins, the enzymatic breakdown of rotting wood emits microbial volatile organic compounds (mVOCs). These are the gases responsible for that "musty" smell in old buildings. They cause headaches, dizziness, fatigue, and nausea. Some, like 3-methyl-2-butanone, have demonstrated mutagenic properties in lab testing. And acrylonitrile, a metabolite found in mVOC-exposed individuals, was classified by the IARC in 2024 as a Group 1 definitive human carcinogen.

The chemicals we add to make wood last

Because wood rots, the industry treats it with powerful biocides. For decades, the standard was chromated copper arsenate (CCA), a mix of chromium, copper, and arsenic. Arsenic is a known human carcinogen linked to cancers of the lung, bladder, skin, kidney, and prostate. It leaches to the surface of treated wood over time and transfers to skin on contact. Children playing on CCA-treated decks are at particular risk.

The EPA phased CCA out of most residential uses in 2004, but it remains legal for foundations, shakes, and shingles, and it persists in millions of older structures.

Pentachlorophenol (PCP), another common wood treatment, is classified by the IARC as a Group 1 human carcinogen with proven links to non-Hodgkin lymphoma. Industrial-grade PCP is almost always contaminated with dioxins and furans, which amplify its toxicity and bioaccumulate in human tissue.

Then there are the flame retardants. Wood burns, so building codes require chemical fire suppression in wood composites and adjacent foams. PBDEs, chlorinated tris (TDCPP), and TBBPA are mixed into insulation, panels, and polyurethane foams. They are not chemically bonded to the material. They migrate out over time, bind to household dust, and are ingested or inhaled by everyone in the house. PBDEs are linked to impaired brain development, lowered IQ, and ADHD in children. TBBPA bioaccumulates in the placenta and breast milk.

What aluminum eliminates

Aluminum is an inorganic metal with a dense, non-porous crystalline structure. It does not absorb moisture. It cannot rot. It provides no nutrients for mold, fungi, or insects. These are not advantages that require engineering. They are inherent properties of the material.

Because aluminum does not rot, it needs no CCA, no pentachlorophenol, no copper azole, no pesticide of any kind. Because it is non-combustible (melting point 1,220F), it needs no flame retardant additives. Because it is not made from organic fibers bonded with adhesives, it emits zero formaldehyde, zero isocyanates, zero terpenes, zero VOCs.

When aluminum needs a finish, it gets powder coated: a dry, solvent-free process that produces a fully cured, inert surface with zero VOC emissions. Compare that to wet paint, which off-gasses solvent compounds for years.

The result is a structural frame that contributes nothing to indoor air pollution. No carcinogens leaching into soil. No mycotoxins forming in wall cavities. No formaldehyde accumulating in a sealed house over decades.

For chemically sensitive people, this is not optional

Multiple Chemical Sensitivity (MCS) is a condition where people experience severe neurological, respiratory, and dermatological reactions to chemicals at concentrations that do not affect most people. Formaldehyde, flame retardants, pesticides, even the natural terpenes from cedar or redwood can trigger debilitating symptoms.

For someone with MCS, living in a wood-framed home is often physically intolerable. The continuous off-gassing from OSB subfloors, the aromatic terpenes from rot-resistant woods, the volatile flame retardants in wall insulation, the constant risk of hidden mold. Every material is a potential trigger.

Architectural guidelines for MCS-safe housing are clear: eliminate porous, outgassing organic materials from the structural envelope. The recommended approach is metal framing, specifically aluminum, because it is the only practical way to achieve a zero-emission structural system.

How this aligns with WELL and LEED certification

The WELL Building Standard v2 sets strict limits on indoor formaldehyde, PM2.5 particulates, and total VOCs. Hitting these targets with wood framing requires expensive active filtration systems running continuously to scrub the air of pollutants the building itself is producing. You are fighting the building.

With aluminum framing, you are doing what WELL actually recommends as the primary strategy: source control. You remove the source of the contamination rather than filtering it after the fact. Compliance becomes a property of the structure, not a mechanical system bolted on to compensate for bad material choices.

What this means for you

If you are building a new home, renovating, or adding an ADU, the framing material is not just a structural decision. It is a health decision that will affect everyone who lives in that space for decades.

Wood framing has been the default for so long that nobody questions it. But the science is clear. The material rots, the rot breeds toxins, and the chemicals we add to prevent the rot are themselves carcinogenic. It is a cycle that aluminum breaks entirely.

You do not need to build the entire house out of aluminum to see a benefit. Replacing the structural frame eliminates the largest single source of indoor chemical exposure. The walls, floor joists, and roof trusses are the biggest surfaces in a home, and they are the ones you can never access after construction is finished. This is especially true for hillside homes in humid climates like Hawaii and the Smokies, where moisture accelerates every one of these problems.