Forty of the 47 guests who swam got sick. "The kids would just ball up into a little ball [from] the pain in their stomachs," she said.

She believes the city knowingly exposed people to the parasite cryptosporidium. Her sick relatives have asked the city for about $8,000 to cover medical, travel and other illness-related expenses, but have been denied.

A Utah County Health Department investigation found the Spanish Fork pool didn't post a mandatory sign telling people with diarrhea they couldn't swim. While the notice was read over the intercom, no employees heard it, the report said.

Broomhead said she would have moved the party to a park if she had seen a sign. Her children worked at the pool, so she knew lifeguards had had diarrhea but were still working, she said.

The county investigation also confirmed sick employees were allowed back in the pool after managers misdiagnosed them with the flu or heat stroke, a gaffe investigators said also occurred at other public and commercial pools.

Broomhead believes managers misdiagnosed the disease to keep the pool open, and her family plans to sue.

Assistant city manager Seth Perrins said the city is "not liable for a crypto outbreak" and noted the pool was closed and super-chlorinated when managers were told it was infected with the parasite.