Which is considered the worst industrial accident in United States history?
Texas City Disaster
On 16 April 1947, the SS Grandcamp, loaded with 8,500 short tons (7,700 t) of ammonium nitrate, exploded in port at Texas City, Texas. 581 died, over 5,000 injured. Using standard chemical data for decomposition of ammonium nitrate makes this equivalent to 2.7 kilotons of TNT exploding. The US Army rates the relative effectiveness factor of ammonium nitrate, compared to TNT, as 0.42. This conversion factor makes the blast equivalent to (0.42)7,770 tons, or 3.2 kilotons of TNT, with the discrepancy between the total energy and relative effectiveness value of the explosive power being due to direct comparisons between high explosives not being as simplistic as comparing total internal energy of each high explosive.
This is generally considered the worst industrial accident in United States history.