LENEXA, Kan. -- Inspectors have identified one problem at Mi Ranchito in Lenexa, but they are not sure if it is "the" problem that resulted in 20 people going to the emergency room on Sunday.

Mi Ranchito, near Interstate 35 and 95th Street, is temporarily closed. A representative from the Kansas Department of Agriculture said on Monday that a dangerous mixture may have been at the root of the problem.

Water One Services inspected the restaurant on Monday morning and found a back flow problem with the carbonated water lines.

The Agriculture Department, which supervises food safety, said the carbonated water back flow had gotten into the copper plumbing lines. They said carbonated water and copper do not mix and can be poisonous and that may have caused several people to become sick on Sunday with vomiting, dizziness and sweating.

This wasn't the first incident for the restaurant. A representative for the Department of Health said that three weeks ago five people went to the hospital for the same symptoms.

All five had eaten at Mi Ranchito and felt sick. But because inspectors did not find any food-related safety issues the restaurant was allowed to stay open.

Mi Ranchito's license has been temporarily suspended at the 95th Street location until the source of the illness is found.

Mi Ranchito officials issued the following statement:

"The source of the illnesses experienced by some of our Lenexa restaurant patrons has been discovered and will be remedied. The appropriate authorities have assured us that the illnesses were not food related and were limited to only the Lenexa location. Mi Ranchito will reopen its Lenexa location as soon as possible in order to serve our loyal customers."