One of the people who contracted botulism from nacho cheese sauce served in a California gas station has died. The state health department is still trying to figure out how the store’s cheese became contaminated with a very rare and incredibly deadly pathogen.

The cheese in question is from Gehl Foods in Wisconsin, the Sacramento Bee reports, and comes in large, shelf-stable pouches. In the food service industry, it’s served to customers from a vat on a steam table or from a cheese dispenser.

The dispenser from the gas station was tested, and was confirmed as the source of botulism that has now made at least 10 people sick, killing one of them. The remaining patients are still hospitalized and on ventilators, since one of the effects of botulism poisoning is paralysis, including of the muscles needed to breathe.

Gehl Foods has tested other pouches of cheese from the same batch that made people sick in California, and they were not contaminated. An outside lab confirmed these findings, and the cheese dip has not been recalled.

The county has cited the gas station for failure to protect food from contamination, but the key question to protect other nacho eaters is how and when the cheese became contaminated. State officials removed the cheese from the gas station, and don’t believe that anyone else in the state is in danger.

Botulism is a rare type of food poisoning, and usually linked to home-canned food gone wrong. It is not associated with giant aseptic pouches of delicious bright orange cheese-like substances that are served hot.

The last massive outbreak of the disease occurred at an Ohio church potluck, where at least people became sick from potato salad made from potatoes that had been improperly canned at home. Early symptoms of botulism include vomiting, double vision, difficulty swallowing, and paralysis that comes on gradually.

Want more consumer news? Visit our parent organization, Consumer Reports, for the latest on scams, recalls, and other consumer issues.