when two commercial divers plan an inspection of a damaged hydroelectric Dam they expect to be in and out in just 15 minutes despite a strict preparation plan an unbelievable error has deadly consequences this is the Fatal breakdown of the lake Oliver Dam accident October 27th 2020 started as a routine workday for Eric Herbert and Alex Paxton they were commercial divers for Glenn industrial group and today's job was a quick check of the lake Oliver Dam in Columbus Georgia the company they worked for had the contract to perform maintenance on the underwater systems the dam was
operated by Georgia power and had its own employees on site managing operations this was a hydroelectric Dam which produces energy from the controlled flow of water through it the chain on one of the control Gates wasn't working right Eric and Alex were supposed to take a look at what exactly was broken so that a formal plan could be made for repairs with more than a decade of experience they were each very comfortable able with the procedures involved in such a dive although they were confident the planning is quite serious and methodical one of the biggest
risks for commercial divers is differential pressure or sources of energy in the water this would include open valves moving water or areas when pressure is different between Chambers this difference in pressure can suck a diver into a hole or up against a grate with deadly force because of this risk the most important pre-dive effort was identifying the potential sources of energy in a facility these were usually listed one by one on a checklist the extensive pre-dive routine would be for the facility to lock out and tag out all of these energy sources lockout tagout or
looto would require each valve or switch to be locked in the closed position and tagged with a label that warns others not to touch until the lotto is removed this procedure is essential to protect anyone in the water the lotto checklist is signed off by two employees of the dam and then validated by the dive company responsible for maintenance on this day the lotto was completed by the lake Oliver Dam employees and each item on the list was double checked and tagged out for maintenance Eric and Alex were ready to get to work but before
they entered the dam they performed their own last check for any differential pressures they were aware of the location of the gates and the priming valve listed on the lotto checklist they dropped their meter into the water to confirm that there was no movement in the water at these locations everything looked good so they positioned themselves above gate three and prepared for entry into the interior of the dam Eric was the supervisor of their shift but offered to run down to check the chain himself he knew that the repairs ahead would require lots of diving
so he offered to go down for this instead of his diving partner Alex waved him off and said he'd jump in to see what was going on the area they were entering was a waterfill chamber where the main gates to the dam resided it was fully connected to the main body of lakew water the door to the gate would be raised by a chain when the gates were open in the open position water flows through to the turbine to produce electricity when it was closed the power plant was not in operation this main flow of
water would move through the pen stock to the turbines where electricity would be produced from the Turning of the turbine system the water would then empty into the lower part of the river when the gates were closed the pen stock pipe would empty out and essentially be an open chamber leading to the turbines on this day after the looto was complete the pen stock was in fact mostly empty because all the gates were locked shut with everything tagged Alex felt perfectly safe diving into the narrow column of water he started at the top of the
chain and slowly moved down as he looked for any defects he was wearing a helmet camera and a light to record what he might find as part of his standard diving gear he had a light and camera on his helmet Communications with the surface tender and an air umbilical continuously supplying him him with air as he moved down the chain past the 20ft mark it was all routine and things looked as expected the chain was fine so he continued to slide down little by little then in a frightening instant he was fully aware of the
sudden pull on his body it only took a second because once it's got you it's got you his arm was closest to the hole and it disappeared down the pipe before he could attempt any response his body was now largely plugging the hole which created an even greater Force where the water was still moving with a violent force of 850 lbs of pressure it was impossible to pull his arm back or resist the force of the column of water he screamed out I'm stuck I'm stuck Alex's arm was being pulled into a 10-in pipe with
overwhelming Force his body was pulled so hard against the surface of the dam he could hardly expand his chest to breathe Eric immediately began to try to pull him up but there was no amount of pulling that could release Alex from this trap Eric and the dam employees were trying to figure out what pressure differential could possibly exist to cause such suction all the lotto locations were rechecked but they were off and tagged as had already been confirmed several times before the dive ever began it took more than 30 minutes to figure out where the
suction came from and to get the valve properly closed so what had gone wrong what Alex Eric and even some of the damn employees didn't know was that there was another valve not listed on the looto checklist this pipe was to Prime the pen stock before opening the main gate if the pen stock was completely empty when the gate was opened a huge rush of water would burst into the chamber and possibly damage the turbine at the end of the pen stock pipe in order to prevent this overwhelming Rush of water there is a small
priming pipe that lets a smaller volume of water into the pen stock to fill it before full operation of the dam this priming system actually had two possible inlets of water there was a flapper type valve similar to what is found in a common toilet and there is a gate type valve with a wheel handle these two valves were only listed once on the lockout form the flapper type valve was locked and tagged for this dive but no one had turned the wheel of the second valve while Alex was stuck it took some time for
the employees to access the wheel to close the valve and remove the pressure differential from the pipe that was sucking Alex so violently this valve shut off was located down off the top of the dam and behind a locked gate despite moving quickly to get the pressure under control it took almost 30 minutes to get the valve shut it seems like a minor oversight but the tiny 10-in opening was a devastating vortex in this chamber of water when a large empty pipe is connected to an entire reservoir of water there is an incredible differential in
pressure this differential is called Delta p in mathematics the symbol Delta means change the P represents pressure so any Delta P situation in diving must be carefully managed as one of the deadliest risks in the profession the looto procedure is used to manage this risk and have several sets of eyes on each potential source of energy or Delta p in the system in this case an unlimited source of 25 ft of water was pressing into a 10-in wide pipe the only way to relieve the pressure was to close the valve to isolate the lake water
from the empty pen stock pipe by the time this was accomplished it was too late for Alex his body was under 850 lbs of pressure and his muscles just could not expand his chest to breathe after just a few minutes he lost Consciousness and died after this devastating tragedy an investigation revealed violations by Georgia power in the operating procedures of the dam the family of Alex Paxton sued Georgia power and received an undisclosed settlement for his wrongful death it seems as if everyone was following the many procedures and plans to make sure that no Delta
P situations exist exist but the main checklist was missing an essential valve the lack of drawings being supplied to the dive company was also a major failure after this incident the lotto checklist was updated to include all valves in the dam the loss of Alex Paxton was caused by a devastating oversight in an essential component of any lockout tagout plan how can you have a list that's important enough to get triple checked for closure but not include an absolutely essential valve on that list I'm goinge and keep a small like just hold your [Applause] [Applause]
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