A spokeswoman for city prosecutors said the accident occurred early Sunday and that investigators are looking into whether the workers died from inhaling toxic fumes. The official spoke on condition of anonymity because she is not authorized to discuss the case.
Building manager Francisco Lopez Bravo told local media the workers were trapped inside the cistern while doing maintenance work.
Lopez Bravo said there are no other risks at the brewery and that it continued to operate on Sunday.
Anheuser-Busch InBev has been trying since June to take over the half it doesn’t already own of Grupo Modelo, which makes Corona and other globally popular beers.