An explosion rocked a pier leading to the famous Underground River in Palawan province on Monday (March 19).

No one was hurt in the explosion, which occurred around 10 a.m. at the pier’s parking lot. The blast however damaged a parked pickup truck. The pier is used to ferry tourists going to the Puerto Princesa Underground River, which is about 15 to 20 minutes away.

Police said the explosion in Sitio Sabang, Barangay Cabayugan, was caused by the overheating of ammonium nitrate stored by illegal fishers in the parking area near the wharf where tours to the Underground River depart. Ammonium Nitrate is used for dynamite fishing.

The police added the explosion occurred because of the heat.