Over 4000 illnesses linked to bottled water in Spain and there are a few theories how the virus got into the hundreds of coolers and fridges across the country. Maybe someone puked in the bottling plant, spreading virus particles all over. My money goes on the source.

Whatever the cause, it’s likely little comfort to those who were barfing as a result.

Live Science reports that the thousands of ill folks consumed water cooler water in early April.

It’s possible that norovirus contaminated the water at its source where it was bottled, said Benjamin Chapman, an associate professor and food safety specialist at North Carolina State University, who was not involved in the investigation. In this case, the spring water was bottled in Andorra, a small country located in the Pyrenees mountains between Spain and France.

Norovirus is spread through fecal matter, and in past outbreaks, drinking water became contaminated when sewage leaked into the water source, Chapman said. Given that the recent outbreak in Spain was so large, with hundreds of bottles affected, “it’s more likely that it would be source contamination,” as opposed to contamination at some later point in the bottling process, Chapman said.

Still, it’s also possible that the water was contaminated at the manufacturing facility. Norovirus is a very hardy virus, Chapman said, and if someone with the illness vomited at a bottling facility, this could contaminate equipment used for bottling the water, Chapman said.