Bathrooms are a prime location for smearing disease-causing microbes all over your hands. Yet, despite societal pressures and prodding signage, a lot of people don’t clean their grimy mitts after a potty break. Some audacious folks just skip the sink all together, while others don’t wash for long enough (experts recommend singing “Happy Birthday” twice in your head) or omit the cleansing soap step. All of those sanitation-slackers threaten to spread disease—particularly in healthcare settings packed with vulnerable patients. But what the latter groups do to dry off their un-cleaned hands may end up setting off a germ bomb.

Researchers have long known that warm hand dryers can launch bacteria into the air—compared to dabbing with paper towels, which unleashes virtually none. But new jet air dryers, made by Dyson, are significantly more problematic—they launch far more viruses into the air, which linger for longer periods of time and reach much farther distances, researchers recently reported in the Journal of Applied Microbiology. This is particularly concerning because viruses, unlike many infectious bacteria, can easily maintain their infectiousness in the air and on surfaces, and just a few viral particles can spark an infection.

“The results of this study suggest that in locations where hygiene and cross-infection considerations are paramount, such as healthcare settings and the food industry, the choice of hand-drying method should be considered carefully,” the authors concluded.

More: Using a Dyson hand dryer is like setting off a viral bomb in a bathroom