Customers and employees were evacuated from Costco at 380 W. Ashlan Ave. in Clovis about 3:15 p.m. Tuesday after a cooling agent leaked from the store's refrigeration system.
Several employees and patrons were treated at the scene for minor breathing problems, said Chad Fitzgerald, a Clovis Fire Department spokesman.
Employees were allowed back into the store about 5 p.m. The store was re-opened to customers an hour later.
Some of the leaked chemical contaminated products in the store. Employees and Fresno County Department of Public Health officials will decide what needs to be thrown out and how to safely dispose of it, Fitzgerald said.