The victims included 41 children age 12 and younger, and 29 parents and coaches, the Vancouver Sun reported.
"We were already in the process of doing our warmup just after 8 [a.m.] and then all of a sudden that smell came out," said Dale Taylor, president of the host Blue Fins swim club. "You know what the [chlorine] smell's like? Well multiply it by a hundred.
"It was nuts, it was really intense, so, we all took off out of there."
Cariboo Memorial Hospital spokeswoman Allison Ruault said most of those treated had their eyes flushed and took showers to get rid of the chlorine. "There was a lot of people as well that required oxygen," Ruault told the newspaper.
All but one victim had been released.
City spokesman Ken MacInnis said the cause of the leak had not been determined.