They say he who smelt it, most likely dealt it. While that logic normally holds true in most situations, it actually wasn’t the case at a Berlin airport today.

According to reports. 53 people were sickened and treated for nausea and sore eyes because of toilet fumes.

But these weren’t the kind of offensive fumes you may be thinking of. It turns out a cleaning crew at the Tegel airport used way too much ammonia when they cleaned the toilets on Friday night. So the toilets were clean, they were just too clean.

The ammonia odor was so strong that even the firefighters who showed up to help fell sick.

Learn from your mistakes, Berlin. Keep your airport toilets filthy like we do here in good ol’ U.S. of ‘eh.