BANGKOK - Dozens of tourists and workers were injured in an explosion caused by mixed chemicals used for cleaning swimming pool at a hotel in Thailand's southern resort town Phuket, local media reported on Saturday.

Staff at the Phuket Orchid Resort, which locates near the most popular Patong beach, confirmed that a cloud of gas was formed by a mixture of chlorine and other cleaning chemicals expanding in a tank beside the pool, the Phuket Gazette reported.

Around 37 people, including 26 tourists and 11 workers, were sent to several hospitals for treatment. Most of them were allowed to leave later, according to news update on a local website.

An officer at the resort said the incident was caused by a pool technician who added wrong mix of chlorine.