In 1989, 23 people were killed in an explosion at Phillips Petroleum Co.’s chemical complex in Pasadena, Texas. The accident resulted from a release of flammable gasses that occurred during regular maintenance operations due to an improperly connected release valve. A vapor cloud formed and traveled rapidly through the polyethylene plant. Within two minutes, the vapor cloud came into contact with an ignition source and exploded with the force of 2.4 tons of TNT.  Ten to fifteen minutes later, that was followed by the explosion of the 20,000- gallon isobutane storage tank, then by the catastrophic failure of another polyethylene reactor, and finally by other explosions, probably about six in total.  Another 314 people were injured and property loss was over $700 million.  Debris was thrown as far as six miles from the site.  OSHA issued 566 willful and 9 serious violations with a combined total proposed penalty of $5,666,200 to Phillips.