San Jose, May 4 (IANS): Costa Rica's National Emergencies Commission (CNE) has announced a red alert after the spill of 180 tonnes of ammonium nitrate into the waters of the country's central Pacific coastline.

The CNE on Sunday declared that the chemical spill was caused after a barge capsized on Saturday afternoon off the coast of the Puntarenas city, Xinhua news agency reported.

The boat capsized due to strong waves in the area. According to the Costa Rican daily 'La Nacion', the two-crew members aboard the vessel were rescued by an emergency personnel.

CNE said the alert was raised as a precautionary measure to ban all sea-related activities such as fishing.

People are now banned from going to the sea between the port towns of Caldera and Puntarenas.

The red alert also imposes the same bans on the opposite coast between Pajaros and Tombor beaches in the Gulf of Nicoya.

The CNE said the Costa Rican health authorities are carrying out an investigation on the impact from the chemical spill.