In what undoubtedly seemed like a good idea at the time, the staff poured the liquid nitrogren into the pool to create a 'smoke on the water' effect. People in the pool began to asphyxiate almost immediately. Some people fell unconscious and slipped under the water, as those outside the pool called for help. The man in a coma is just 21-years-old.

Contrary to the Daily Mirror's report, the liquid nitrogen did not react with the chlorine.

Geekosystem explains:

Nitrogen is pretty inert, and shouldn’t have a major reaction with anything in the pool. Instead, chemist Paul Bracher explains that the liquid nitrogen boiled off after being poured into the pool, expanding quickly and displacing the oxygen around the pool. That meant that pretty soon, everyone in the pool was attempting to breathe nitrogen instead of oxygen, which is not a thing that works, as demonstrated in this video.

Mexican authorities in La Colonia Granjas El Palote are now investigating to determine if any criminal charges are to be laid.