Yeah, that was pretty awful. They pushed formula as being more healthy, which it isn't, and it was made extra bad because they did so in countries that didn't have clean water. Adults in those countries have built up somewhat of an immunity to the diseases in the water, but infants don't have that (they get it from their mother's milk!)

So parents mixed the water with the formula, giving their infants diseases they didn't have any protection against because they didn't get any antibodies from their mother's milk