People were left standing outside a leisure centre after it was evacuated due to a "chlorine incident".
Users of Strood Sports Centre, in Watling Street, were told to leave the building due to too much chlorine in the pool.
The high level of chlorine was also impacting people in the sauna and the centre was temporarily closed.
Fire crews and ambulances are at the scene.
Spokesman for the ambulance service, Rich Airey, said: "We sent a large number of vehicles to the scene and they are still there.
"We were called following reports of fumes at the leisure centre.
"The swimming pool was evacuated. We were able to send the majority of people home but two or three will be taken to Medway Hospital.
"Several people were complaining of shortness of breath.
"Can we remind people to only call 999 in an emergency as a large number of our crews are at the scene."
Four fire engines rushed to the centre shortly before 3.25pm.
A Kent Fire and Rescue Service spokesman said: "The pool has been evacuated as a precaution and hazardous material officers have isolated what is believed to be the leak source.
"They are now inspecting the centre and measuring gas and oxygen levels to make sure it's safe for people to go back inside."
Carrie McKenzie, assistant director of transformation at Medway Council, said: “Strood Sports Centre and main swimming pool have now reopened.
"The centre was temporarily closed earlier this afternoon as a precautionary measure following reports of a strong smell of chlorine.
"KFRS attended and assessed and have confirmed that the site is safe to reopen.
"The teaching pool will remain closed for further checks later this evening."