Pick up the disinfectant spray under your sink and check the active ingredient. If it lists Benzalkonium Chloride, Alkyl Dimethyl Benzyl Ammonium Chloride, or any compound ending in "ammonium chloride," you are looking at a quat. Quaternary ammonium compounds are in most conventional disinfectants, fabric softeners, and dryer sheets. Their presence in consumer products increased significantly during and after the COVID-19 pandemic.
The No Nines™ Standard™ excludes quats as Category 1 of the nine chemical categories we will not formulate with. This post explains what quats are, where they appear, what published research has found, and what we use instead.
What are quaternary ammonium compounds?
Quaternary ammonium compounds, commonly called quats or QACs, are a family of positively charged nitrogen-based chemicals. They function as surfactants and antimicrobial agents. The "quaternary" part of the name refers to the four organic groups attached to a central nitrogen atom, which gives the molecule its permanent positive charge and its ability to disrupt microbial cell membranes.
There are hundreds of individual quat compounds. The ones most common in consumer cleaning products include Benzalkonium Chloride (BAC), Alkyl Dimethyl Benzyl Ammonium Chloride (ADBAC), Didecyl Dimethyl Ammonium Chloride (DDAC), and Cetrimonium Chloride. You will find them listed on labels in slightly different phrasing depending on the manufacturer, but the pattern is consistent: a long chemical name ending in "ammonium chloride" or "ammonium saccharinate."
Quats appear in disinfectant sprays, disinfecting wipes, fabric softeners, dryer sheets, some hand sanitizers, and many products marketed as "antibacterial." They are effective antimicrobials. That is not in dispute. The question the No Nines Standard addresses is whether the trade-offs are worth it when alternatives exist.
What the research says
Research into the health effects of quats has expanded considerably in the past decade. The findings fall into three main areas: respiratory effects, endocrine disruption, and population-level exposure data.
Respiratory effects. The Association of Occupational and Environmental Clinics (AOEC) lists both DDAC and ADBAC as asthmagens, meaning they are recognized as substances capable of causing new-onset occupational asthma. A 2021 multicenter cohort study published in The Journal of Allergy and Clinical Immunology: In Practice documented cases of occupational asthma caused by quaternary ammonium compound exposure in healthcare and cleaning workers. The Mount Sinai Occupational Medicine program has published guidance noting that workers exposed to QACs can experience respiratory system irritation, inflammation, and outcomes consistent with both occupational asthma and work-exacerbated asthma.
Most of this respiratory research involves occupational settings where exposure concentrations are higher than typical household use. However, the AOEC asthmagen designation applies to the chemical class itself, not to a specific concentration threshold, which means the compounds have an established capacity to sensitize the respiratory system.
Endocrine disruption. Animal studies have raised concerns about quats and reproductive health. Research led by Terry Hrubec at Virginia Tech found that ambient exposure to a mixture of ADBAC and DDAC, common disinfectant ingredients, decreased fertility in mice. A follow-up study published in Reproductive Toxicology (2015) showed that the compounds targeted both male and female reproductive processes, reducing sperm concentration, sperm motility, and ovulation rates. In vitro research has also demonstrated that the quats cetylpyridinium chloride (CPC) and BAC inhibit mitochondrial complex I and show antiestrogenic activity at low micromolar concentrations, according to a 2018 study in Toxicology In Vitro.
This research remains largely in the animal and cellular domain. Translating these findings directly to human health outcomes at household exposure levels is not yet possible. But the biological mechanisms are plausible: all steroid hormones are derived from cholesterol, and Hrubec's 2021 human pilot study found that cholesterol synthesis intermediaries were significantly disrupted in blood samples with higher QAC concentrations.
In a 2021 pilot study published in Environmental Science & Technology, Hrubec et al. detected QACs in up to 80% of human blood samples tested, with concentrations showing a dose-dependent increase in inflammatory cytokine levels.
Biomonitoring data. That same study measured five QACs (BAC C10-C16, DADMAC C10:C10) in human plasma from a convenience sample of 43 participants and found total QAC concentrations ranging from 0.01 to 58.7 ng/mL. While the sample size was small, the detection frequency was notable. A broader 2023 review article in Environmental Science & Technology, titled "Quaternary Ammonium Compounds: A Chemical Class of Emerging Concern," consolidated the existing literature and concluded that QACs warrant further scrutiny as an environmental and health concern, particularly given the sharp increase in disinfectant use during the COVID-19 pandemic.
Where quats show up in your home
The most obvious sources are disinfectant sprays and wipes. Products marketed for kitchen counters, bathroom surfaces, and general-purpose disinfection frequently rely on quats as their primary active ingredient. But the less obvious sources may contribute more cumulative exposure.
Fabric softeners and dryer sheets use quats (typically ditallow dimethyl ammonium chloride or similar compounds) to coat textile fibers, reducing static and imparting softness. This means quat residues remain on clothing, bedding, and towels that stay in prolonged contact with skin. Scented laundry products layer this exposure with other chemical categories the No Nines Standard addresses, including synthetic fragrance.
Research has documented that quats persist on surfaces and accumulate in household dust. A study published in Environmental Science & Technology Letters (2024) found QACs in paired blood and indoor dust samples from US homes, and a separate analysis showed that QAC concentrations in household dust had nearly doubled when compared to pre-COVID samples. Because QACs carry a positive charge, they bind readily to negatively charged surfaces like countertops, floors, and fabrics, and they are not easily biodegraded in indoor environments.
A separate and still-developing area of research concerns antimicrobial resistance. Several studies have identified correlations between benzalkonium chloride tolerance and antibiotic resistance in bacteria. A 2024 review in Science of the Total Environment noted that sub-lethal environmental concentrations of QACs may promote resistance gene transfer in bacterial populations. This research is not yet settled, and the clinical significance for household settings is still being evaluated. But the possibility that widespread quat use could contribute to antimicrobial resistance is a concern the scientific community is actively investigating.
What No Nines uses instead
Every No Nines cleaning product is formulated without quats. For antimicrobial function, we use hypochlorous acid, abbreviated as HOCl.
HOCl is the same molecule your white blood cells produce to fight pathogens. Neutrophils generate it through the myeloperoxidase enzyme system as part of the innate immune response. It is effective against bacteria, viruses, and fungi, but unlike quats, it does not persist on surfaces or accumulate in dust. HOCl breaks down into trace amounts of salt and water, leaving no antimicrobial residue behind.
This is not a novel or unproven chemistry. HOCl has been used in wound care, food safety, and water treatment for decades. What has changed is the ability to stabilize it effectively in consumer-ready formulations.
Our Whole Home HOCl Cleaner uses this chemistry for everyday surface cleaning. The Pet Deodorizer uses it for odor elimination without quat residues on pet bedding or fur. And the Laundry Rinse replaces the antimicrobial function that conventional laundry products achieve through quats, without leaving persistent residues on fabric.
For more on how HOCl compares to conventional cleaning chemistries, including bleach, see our post on bleach in cleaning products.
The bottom line
Quats are effective antimicrobials. They have been the default active ingredient in consumer disinfectants for decades, and their use surged during the pandemic. But research from the AOEC, Virginia Tech, and multiple biomonitoring studies has raised legitimate questions about respiratory sensitization, endocrine disruption, surface persistence, and potential contributions to antimicrobial resistance.
The No Nines Standard excludes quats as Category 1 because alternatives exist that provide antimicrobial function without these trade-offs. HOCl delivers comparable efficacy, breaks down cleanly, and does not accumulate in your home.
This is not about fear. It is about having enough information to make a choice, and having a product line that reflects that choice clearly.
