What caused 12,000 deaths in 4 days in London in 1952?

Question

Where was the industrial accident on 2-3 December 1984 that caused the deaths of 3,000 to 16,000 people, for which 7 ex-employees were convicted in June 2010 and sentenced to 2 years imprisonment & a fine of about US$2,000 each?

Answer 1

Smog
It lasted from 5 to 9 December 1952. At the time, medical reports estimated that 4,000 had died prematurely and 100,000 made ill due to the smog's effects on the human respiratory tract. More recent research suggests that the number of fatalities was around 12,000.