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DUPONT YERKES CHEMICAL PLANT EXPLOSION

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Language: en

00:00:03.600
on November 9th 2010 a powerful
00:00:08.240 00:00:08.250 explosion shook the DuPont chemical
00:00:10.160 00:00:10.170 manufacturing plant in Tonawanda New
00:00:12.860 00:00:12.870 York a suburb of Buffalo a contract
00:00:16.460 00:00:16.470 worker was performing maintenance work
00:00:18.500 00:00:18.510 on a tank that unknown to him contained
00:00:21.710 00:00:21.720 flammable gas the explosion blew the top
00:00:25.730 00:00:25.740 of the tank
00:00:26.720 00:00:26.730 throwing the welder to the ground and
00:00:28.820 00:00:28.830 killing him instantly a second contract
00:00:31.880 00:00:31.890 worker was burned hot work accidents
00:00:36.260 00:00:36.270 occur when workers are welding cutting
00:00:39.080 00:00:39.090 or grinding near flammable vapor
00:00:45.580 00:00:45.590 Donna Wanda facility manufactures a
00:00:47.830 00:00:47.840 polymer known as ted'll are used in
00:00:50.590 00:00:50.600 solar panels and Corian for use in
00:00:53.920 00:00:53.930 countertops the process of producing Ted
00:00:57.370 00:00:57.380 lire began with a chemical reaction to
00:01:00.190 00:01:00.200 convert flammable vinyl fluoride gas
00:01:02.380 00:01:02.390 into a slurry of polyvinyl fluoride
00:01:05.380 00:01:05.390 polymer or PV F in water the PBF slurry
00:01:10.210 00:01:10.220 then passed through separators
00:01:12.600 00:01:12.610 compressors recycled unreacted vinyl
00:01:15.730 00:01:15.740 chloride gas into the process while a
00:01:18.609 00:01:18.619 small flash tank released residual vinyl
00:01:21.700 00:01:21.710 fluoride into the atmosphere
00:01:23.790 00:01:23.800 finally the slurry was transferred to
00:01:26.590 00:01:26.600 one of three insulated holding tanks
00:01:28.870 00:01:28.880 usually tank number three tanks one and
00:01:32.980 00:01:32.990 two were reserved for slurry overflow
00:01:35.290 00:01:35.300 tank one normally remained empty
00:01:42.679 00:01:42.689 we're 22nd
00:01:44.789 00:01:44.799 10 the tedlar process underwent a
00:01:47.730 00:01:47.740 planned shutdown during which workers
00:01:50.219 00:01:50.229 removed the asbestos insulation on tanks
00:01:53.730 00:01:53.740 1 & 2
00:01:54.859 00:01:54.869 removing the insulation revealed that
00:01:57.480 00:01:57.490 the agitators supports for the tanks
00:01:59.730 00:01:59.740 were heavily corroded dupont directed
00:02:02.700 00:02:02.710 contractors to repair the supports which
00:02:05.490 00:02:05.500 would involve welding and grinding on
00:02:07.590 00:02:07.600 tanks 1 & 2 the hot work on tank 2
00:02:11.070 00:02:11.080 occurred during the shutdown without
00:02:12.900 00:02:12.910 incident but the repairs on tank 1 were
00:02:15.720 00:02:15.730 delayed while parts were ordered DuPont
00:02:18.809 00:02:18.819 personnel determined that it would be
00:02:20.910 00:02:20.920 safe to perform hot work on tank 1 after
00:02:24.270 00:02:24.280 the restart on November 7th dupont
00:02:27.630 00:02:27.640 operators locked all five valves leading
00:02:30.479 00:02:30.489 to and from tank 1 in the closed
00:02:32.789 00:02:32.799 position in order to stop potential
00:02:35.699 00:02:35.709 slurry flow the tanks agitator motor was
00:02:38.940 00:02:38.950 also locked out however DuPont personnel
00:02:41.940 00:02:41.950 did not block the flow of gas inside the
00:02:44.970 00:02:44.980 overhead piping or overflow line that
00:02:48.240 00:02:48.250 connected the vapor space of all three
00:02:50.340 00:02:50.350 tanks they mistakenly believed that
00:02:52.740 00:02:52.750 flammable vinyl fluoride gas could not
00:02:55.080 00:02:55.090 reach any of the slurry tanks but the
00:02:57.900 00:02:57.910 CSB investigation found that even in
00:03:00.690 00:03:00.700 normal operations vinyl fluoride was not
00:03:03.840 00:03:03.850 completely removed from the slurry and
00:03:05.879 00:03:05.889 was always present in the slurry tanks
00:03:08.580 00:03:08.590 in varying amounts when the process
00:03:11.460 00:03:11.470 restarted on November 6th the flammable
00:03:14.400 00:03:14.410 gas was able to travel from tanks 2 & 3
00:03:17.000 00:03:17.010 through the open overflow line into tank
00:03:20.610 00:03:20.620 1
00:03:23.730 00:03:23.740 on the morning of November 9th a DuPont
00:03:26.730 00:03:26.740 technician tested the atmosphere above
00:03:29.190 00:03:29.200 tank 1 we're welding would later take
00:03:31.740 00:03:31.750 place there were also two continuous air
00:03:34.740 00:03:34.750 monitors in the vicinity no flammable
00:03:37.650 00:03:37.660 gas was detected and the hot work was
00:03:40.470 00:03:40.480 cleared to begin but no testing was done
00:03:43.410 00:03:43.420 to measure or monitor the atmosphere
00:03:46.410 00:03:46.420 inside the tanks were unknown to the
00:03:49.470 00:03:49.480 contractors the flammable gas was at
00:03:52.200 00:03:52.210 dangerous levels around 9 a.m. to
00:03:56.310 00:03:56.320 contract workers began welding and
00:03:58.530 00:03:58.540 grinding on tank 1 the welder connected
00:04:01.620 00:04:01.630 his safety harness to the tanks agitator
00:04:03.750 00:04:03.760 support and worked on top of the tank as
00:04:06.810 00:04:06.820 the foreman looked on from the nearby
00:04:09.120 00:04:09.130 catwalk at approximately 11 a.m. the
00:04:12.870 00:04:12.880 welder was repairing corroded portions
00:04:15.120 00:04:15.130 of the agitator support beams directly
00:04:17.729 00:04:17.739 above the flammable gas a hole around
00:04:20.640 00:04:20.650 the agitator shaft may have provided a
00:04:23.400 00:04:23.410 pathway for ignition welding sparks
00:04:25.950 00:04:25.960 could fall into the tank even as
00:04:28.620 00:04:28.630 flammable gas might drift upward toward
00:04:31.230 00:04:31.240 the sparks the ignition of the vinyl
00:04:33.390 00:04:33.400 fluoride caused a powerful
00:04:36.620 00:04:36.630 the force of the blast blew the top of
00:04:38.900 00:04:38.910 the tank almost completely off a flash
00:04:42.170 00:04:42.180 fire erupted that consumed the flammable
00:04:44.480 00:04:44.490 gas and quickly burned out the welder
00:04:47.630 00:04:47.640 was thrown to the ground killed
00:04:49.610 00:04:49.620 instantly from blunt force trauma the
00:04:52.610 00:04:52.620 Foreman's face and arms were burned
00:04:59.989 00:04:59.999 DuPont regarded most of the tedlar
00:05:02.119 00:05:02.129 production process as covered under the
00:05:04.579 00:05:04.589 OSHA standard for process safety
00:05:06.469 00:05:06.479 management or PSM and therefore subject
00:05:09.979 00:05:09.989 to stricter operating and maintenance
00:05:11.929 00:05:11.939 requirements but DuPont personnel did
00:05:15.109 00:05:15.119 not include the slurry tanks in the
00:05:17.209 00:05:17.219 facility's PSM program in a 2009 process
00:05:21.559 00:05:21.569 hazard analysis DuPont erroneously
00:05:24.499 00:05:24.509 concluded that flammable vinyl fluoride
00:05:27.199 00:05:27.209 gas could never reach the tanks in
00:05:29.600 00:05:29.610 dangerous quantities
00:05:35.080 00:05:35.090 two additional factors may have
00:05:37.270 00:05:37.280 contributed to the tragedy prior to the
00:05:40.510 00:05:40.520 explosion
00:05:41.320 00:05:41.330 DuPont personnel had discovered that
00:05:43.689 00:05:43.699 slurry tank number two had a hole in a
00:05:46.600 00:05:46.610 liquid trap which was designed to
00:05:49.030 00:05:49.040 prevent the flow of gas from the flash
00:05:51.100 00:05:51.110 tank without a liquid seal in the trap
00:05:53.740 00:05:53.750 there was an additional pathway for
00:05:56.260 00:05:56.270 vinyl fluoride gas to flow into the
00:05:58.450 00:05:58.460 tanks
00:05:59.490 00:05:59.500 however this hazard went unrecognized
00:06:02.020 00:06:02.030 and DuPont engineers concluded that it
00:06:05.200 00:06:05.210 would be safe to return the tank to
00:06:07.000 00:06:07.010 service no formal management of change
00:06:10.330 00:06:10.340 with you was conducted further adding to
00:06:14.020 00:06:14.030 the danger on November 8th there was a
00:06:16.690 00:06:16.700 malfunction in a compressor used a strip
00:06:19.150 00:06:19.160 vinyl fluoride gas from the PVF slurry
00:06:21.640 00:06:21.650 as a result the slurry contained more
00:06:25.000 00:06:25.010 than the normal amount of vinyl fluoride
00:06:27.029 00:06:27.039 once again
00:06:28.659 00:06:28.669 DuPont personnel did not formally
00:06:31.210 00:06:31.220 analyze the safety impact of continuing
00:06:34.240 00:06:34.250 to operate with a malfunctioning
00:06:35.580 00:06:35.590 compressor
00:06:40.660 00:06:40.670 final report the CSB recommended that
00:06:43.510 00:06:43.520 DuPont revised its corporate policies to
00:06:46.480 00:06:46.490 require atmospheric monitoring inside
00:06:49.210 00:06:49.220 tanks before and during any hot work and
00:06:52.870 00:06:52.880 the board recommended that Japan require
00:06:55.600 00:06:55.610 all process piping including vent lines
00:06:58.840 00:06:58.850 on tanks to be positively isolated
00:07:01.870 00:07:01.880 before authorizing any hot work

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