Inhaling Common Disinfectants Increases Toxicity and Lung Risk

Research from the University of California, Davis, indicates that inhaling common disinfectant chemicals may be significantly more toxic than swallowing them, according to a study published in Environmental Science and Technology and reported on March 30, 2026.

The study focused on quaternary ammonium compounds, known as QACs, which are widely used in cleaning and disinfectant products. Researchers found that when these compounds are inhaled, they can cause substantial lung injury at blood exposure levels similar to those observed in humans.

Increased Toxicity Through Inhalation

The findings suggest a stark difference in how the body reacts to QACs depending on the route of exposure. Gino Cortopassi, a biochemist and pharmacologist with the UC Davis Weill School of Veterinary Medicine and the study’s lead author, highlighted the severity of the results.

The surprising result of this study was that these compounds, when inhaled, caused 100-fold more lung injury and 100-fold more lethality compared to oral ingestion

Gino Cortopassi

While QACs are not highly volatile—meaning they do not produce fumes on their own—they are frequently used in disinfectant sprays. This delivery method allows the chemicals to enter the lungs directly.

Common Sources of QAC Exposure

Quaternary ammonium compounds have been utilized as disinfectants since the 1940s and are sold under trade names such as Roccal and Lysol. Beyond disinfectant sprays, these chemicals are found in a variety of household and personal care products, including:

• Fabric softeners and dryer sheets
• Mouthwash
• Nasal sprays
• Eye drop disinfectants
• Certain herbicides

The potential for systemic exposure is high. In 2021, Cortopassi and his colleagues conducted research that found detectable concentrations of QACs in the blood of 80% of the study participants, challenging previous assumptions that these compounds did not enter the bloodstream.

Links to Respiratory Disease

The UC Davis findings raise concerns regarding whether airborne exposure to these cleaning products contributes to the development of chronic respiratory conditions. Specifically, researchers are questioning if such exposure is linked to chronic obstructive pulmonary disease (COPD) or asthma.

This research aligns with earlier observations regarding occupational health. A report from October 18, 2019, noted that several European studies had identified an increased risk of COPD among those with occupational exposure to disinfectants. Those studies also reported higher rates of death due to COPD and an accelerated decline in lung function.

The current UC Davis study, conducted using mice, provides a mechanism that may explain these risks by demonstrating the high toxicity of inhaled QACs compared to other forms of exposure.