The Green Acres Mall in Valley Stream was evacuated Sunday as crews responded to a hazmat situation.
Fire officials say a mall maintenance worker was cleaning a sump pump in a garage tunnel when he dropped bleach and ammonia down a drain.
The chemicals created a strong odor, and the mall was evacuated as a precaution.
Hazmat crews flushed out the sump pump, officials say. The mall has since been reopened.
No injuries were reported.