Formaldehyde is a colorless chemical compound with a strong, distinct odor that exists as a gas at room temperature. It is widely utilized across various industries and found in numerous products, often as a preservative or in the manufacturing of resins. Despite its broad applications, formaldehyde is a substance that raises notable health concerns, particularly due to its established link to cancer.
Understanding the Cancer Link
Major health organizations classify formaldehyde as a known human carcinogen. The International Agency for Research on Cancer (IARC), part of the World Health Organization (WHO), categorizes formaldehyde as “carcinogenic to humans” (Group 1). Similarly, the US National Toxicology Program (NTP) lists formaldehyde as a “known to be a human carcinogen”. The US Environmental Protection Agency (EPA) also classifies formaldehyde as “carcinogenic to humans by the inhalation route of exposure.”
The strongest evidence links formaldehyde exposure to nasopharyngeal cancer, a rare cancer affecting the part of the throat behind the nose, and myeloid leukemia, a cancer of the blood and bone marrow. Studies of workers with high occupational exposure, such as embalmers and industrial workers, have shown increased risks for these cancers. While the evidence is strongest for these specific cancers, the EPA notes that findings also suggest increased risks for other types of cancer, including nasal sinus cancer.
How Formaldehyde Affects Cells
Formaldehyde is understood to contribute to cancer development through its genotoxic properties, meaning it can directly damage genetic material within cells. It reacts with DNA and proteins, forming various types of lesions:
DNA adducts
DNA intra-strand crosslinks
DNA inter-strand crosslinks
DNA-protein crosslinks
These crosslinks can impede normal cellular processes such as DNA replication and transcription, which are necessary for cell function and division.
If these DNA lesions are not properly repaired by the cell’s natural defense mechanisms, they can lead to mutations during DNA replication. Research indicates that formaldehyde-induced DNA damage can accelerate the aging of blood stem cells, increasing the likelihood of blood cancers. This damage can also result in chromosomal changes, including breaks and aneuploidy, which is an abnormal number of chromosomes within a cell, disrupting normal cell growth and promoting uncontrolled cell proliferation.
Everyday Exposure Sources
Individuals can encounter formaldehyde in a variety of everyday environments and products, with exposure primarily occurring through inhalation. Building materials are a significant source, especially pressed-wood products like particleboard, plywood, and medium-density fiberboard, which often use formaldehyde-based resins as adhesives. These materials can continuously release formaldehyde gas into the air, a process known as off-gassing.
Household products also contribute to exposure, including:
Glues
Paints
Varnishes
Certain cleaning agents
Cosmetics
In industrial settings, workers in manufacturing plants, laboratories, and funeral homes may experience higher exposure levels due to direct handling or prolonged presence near formaldehyde-containing substances. Additionally, environmental sources such as vehicle exhaust, tobacco smoke, and emissions from unvented fuel-burning appliances can introduce formaldehyde into indoor and outdoor air.
Reducing Your Exposure
Minimizing formaldehyde exposure involves several practical steps, particularly focusing on indoor environments where levels are often higher than outdoors. Improving ventilation in homes and workplaces is an effective strategy; opening windows and doors regularly or using exhaust fans, especially when new materials are introduced, helps to dilute airborne formaldehyde concentrations. Maintaining moderate temperatures and reducing humidity levels with air conditioning and dehumidifiers can also decrease the rate at which formaldehyde is released from products.
When purchasing new items, selecting low-formaldehyde or formaldehyde-free products is beneficial. Look for labels such as:
TSCA Title VI Compliant
California Air Resources Board (CARB) Phase 2 Compliant
No-added formaldehyde (NAF)
Ultra-low-emitting formaldehyde (ULEF)
on composite wood products and furniture. Avoiding tobacco smoke indoors significantly reduces formaldehyde levels, as cigarette smoke is a known source of the chemical. Regulatory bodies like the EPA and OSHA set standards for formaldehyde emissions in products and workplaces, which help to limit overall exposure.