Another incident where "tryout" was not done

On July 23, 2009, Employee #1 and a coworker, both contract employees specializing in preparation of refinery equipment for entry, were installing blinds in piping preparatory to confined space entry for inspection and maintenance. The pressure vessel was removed from service, cleaned, flushed and drained. The column was under a nitrogen purge of approximately one psi to facilitate the draining. Employee #1 and the coworker encountered pressurized steam at the top of the vessel while installing the blinds. At the bottom of the vessel, Employee #1 and the coworker began to loosen flange bolts when they encountered hot water leaking from the 16 bolt, 300 lb flange. As Employee #1 loosened one of the last two bolts, the flange opened and Employee #1 was sprayed with 197 degree F hot oily water. Employee #1 sustained first and second degree burns to the neck, arms, shoulder and upper back. Employee #1 was hospitalized. It was determined the Controlling Employer did not verify that the equipment had been deenergized.
Source: osha.gov