After an afternoon press conference that got underway later than scheduled, officials from the National Commission on Emergencies (Spanish initials: CNE) in Costa Rica declared that the Red Alert issued earlier on Sunday should be downgraded to Yellow, which means that swimmers and surfers can reenter the ocean waters from Port of Caldera north to the city of Puntarenas (where the Double Tree Hilton is located) and across the Gulf of Nicoya to San Lucas Island, Playa Pájaros, Paquera, Playa Quesera, Ballena Bay (not to be confused with a similarly named coastal community in the southern Pacific), Playa Tambor, Tortuga Island, and Cedros Island.

As previously reported by The Costa Rica Star, a barge carrying diesel fuel and 180 tons of ammonium nitrate capsized and sunk off Puntarenas, near the Port of Caldera. Ammonium nitrate is normally used as a fertilizer and could be toxic when high concentrations come in contact with the eyes, skin, or membranes. When concentrated ammonium nitrate dissolves in water, it turns into a liquid form that can be toxic.

A preliminary laboratory analysis by the CNE has shown that the ammonium levels in the affected waters are not as toxic to human life as previously thought; however, reports of dead fish are still a concern that some level of environmental damage can be expected. The CNE further explained that a fisheries alert remains in effect; to this end, anglers should not fish in the affected area until further notice. It is important to note that it is currently safe to purchase fish and seafood from retail stores in Costa Rica since the National Coast Guard Service and the Fisheries Institute are enforcing a no-catch period.

Chemical engineers and biologists in Costa Rica have estimated that it will take about 72 hours for the ocean to completely filter out the toxic levels of ammonium.