Quaternary ammonium compounds (quats) are a class of chemicals used widely in disinfectants, sanitizers, and other consumer products due to their antimicrobial properties. They are classified as pesticides by the U.S. Environmental Protection Agency (EPA) and are regulated accordingly, with label instructions considered legally binding.

Quats function by disrupting cell membranes, particularly effective against Gram-positive bacteria, and are used in various applications including winery sanitation, household cleaners, fabric softeners, and personal care products.

Safety data sheets (SDS) for quat-based products highlight significant health hazards. These compounds are corrosive to the eyes, skin, and respiratory system, and can cause severe irritation or burns upon exposure. Ingestion may lead to gastrointestinal distress, while inhalation of mists or vapors can irritate the throat and respiratory tract, potentially causing central nervous system effects such as headaches, dizziness, and drowsiness. Prolonged or chronic exposure has been linked to skin and eye irritation, respiratory issues, and even the development of asthma in some individuals. Some studies have also associated exposure to specific quats like ADBAC and DDAC with developmental and fertility problems in laboratory animals.

Quats are highly adhesive and can degrade slowly, which increases the risk of residue buildup on surfaces. This residue can lead to off-aromas and undesirable characters in products like wine if not thoroughly removed, with a taste threshold for quats in wine reported at 15 mg/L. The EPA is currently updating risk assessments for quats, which were previously released for public comment in 2021, reflecting ongoing scrutiny of their safety profile.

Common quat ingredients include alkyl dimethyl benzyl ammonium chloride (ADBAC), didecyl dimethyl ammonium chloride (DDAC), and related compounds, which are often found in sprays, wipes, and disinfectant solutions. Products such as Quat San 10 contain mixtures of these compounds, with specific ingredients like ADBAC and DDAC listed in their SDS. Despite their effectiveness, concerns have been raised about the long-term health and environmental impacts of quats, especially with increased use during the COVID-19 pandemic.