The Lancaster County Central Park pool is closed because a child had diarrhea Tuesday and it will remain closed Wednesday.
Paul Weiss, the park's director, said the incident happened during swim lessons about 11 a.m. and staff reacted immediately.
To deal with the contamination and comply with state clean-up protocol, the pool added chlorine to a high level and must maintain that level for 25 hours, Weiss said.
The high chlorine will then be allowed to return to appropriate levels. Then, the pool can reopen. Weiss said the pool should reopen Thursday. Pool attendance varies, Weiss said, but weekday attendance generally ranges from 200 to 400 people.
Weiss, who has been with the parks department more than 20 years, said this is the first such mishap he or staff was aware of.
The pool has dealt with solid stool incidents in the past, but they can be dealt with in about 40 minutes, Weiss said.
Diarrhea can indicate illness, such as from cryptosporidium, which is why more significant protocols must be followed.