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Tuesday 2-ball

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Trees and Utilities Conference 2017

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Tuesday 2-ball

  1. 1. Everything Begins with Safety John Ball South Dakota State University NREMT-AEMT, PHTLS CTSP, BCMA
  2. 2. Between 15 and 20% of tree worker fatalities are from contact with an electric current. Electrical shock is the physiological reaction to the passage of electrical current through the body. Electrocution is death from an electrical shock (cardiac arrest).
  3. 3. First US electrical current fatality was in October 1881. The United States Electric Lighting Company in Buffalo gave a lighting exhibition in a factory building at 296 Washington Street. Samuel Smith fell and made contact with a wire connected to a 250 AC generator. The crowd was surprised how peacefully he died, “It was as if he fell in sleep”, remarked one observer.
  4. 4. Outcome of high voltage (over 1 kV) high amperage (over 200 mA) contact is asystole, few tetanic contractions and deep burns. Joule’s law; heat generated is proportional to the amperage squared. Outcome of low voltage (under 1 kV) low amperage (under 75 mA) contact is v-fib, tetanic contraction and superficial burns.
  5. 5. First US electrocution was on August 6, 1890 to William Kemmler. After practicing on a horse, they wired him in a chair with 1,000 volts for 17 seconds, tried again with 2,000 volts until he burned. The witnesses were horrified by the manner of his death. Westinghouse commented “They would have done better with an axe.”
  6. 6. Contact with an electrical conductor is different from being struck by lightning.
  7. 7. Most cloud- ground strikes are a series of strokes each lasting 1,000,000th of a second. Your skin has enough resistance so it passes over you during this brief period.
  8. 8. Lichtenberg’s flower caused by the rupture of capillaries in the skin.
  9. 9. Contact with high voltage for longer duration (greater than 1000 volts) results in burns.
  10. 10. The man was on the bucket truck using an extended saw to trim the trees from the wires. Two other co-workers were below the bucket truck when the man was shocked.
  11. 11. Full-thickness burns – involve subcutaneous layers, muscle, bones, internal organs. Skin is dry, leathery, white to brown and charred. May have no pain. Partial-thickness burns – involves some portion of the dermis. Skin is moist, white to red and blistered. Intense pain. Superficial burns – only involve the top layer of skin, the epidermis. The skin turns red. Painful.
  12. 12. Partial thickness burn
  13. 13. So we should treat lines with a lot of respect
  14. 14. Sawdust flies as a worker cuts tornado damaged limbs away from power lines in west Arlington, Texas (AP Photo/Fort Worth Star-Telegram, Ron T. Ennis) But we don’t….
  15. 15. Tree workers comprise about 2% of all electrocutions.
  16. 16. Who is killed performing tree work? Guys (99%) White (non-Hispanic) guys (70%) Old (more than 45 years old) white guys (44%)
  17. 17. Electrocutions tend happen to the younger (20-34 years old) and less experienced worker. About 40% of incidents occur to workers with less than 1 year experience.
  18. 18. Are there difference in incident types between utility and commercial arborist? Not really
  19. 19. Struck by tree or branch – 39% of fatalities Castillo and Menendez. 2009. MMWR 58 (15) 389-393
  20. 20. Struck by chain saw – 2% of fatalities
  21. 21. Caught-in chipper – 5% of fatalities
  22. 22. Falls from/with tree – 21% of fatalities
  23. 23. Falls from/with aerial lift – 10% of fatalities
  24. 24. Struck by vehicles – 6% of fatalities
  25. 25. It does differ with electrical shock. About 21% of electrocutions occur during line clearance; the remaining 79% mostly during residential (commercial or municipal) tree pruning and removal.
  26. 26. Direct contact Fatal Nonfatal Aerial devise operator 19 1 Climber 6 2 Ground worker 2 0 Unpublished data Tree Worker Fatalities (2004-2011)
  27. 27. Direct contact occurs mostly to aerial lift operators during line clearance.
  28. 28. A neighbor who came out of his house after the power went out said he knew the situation was bad when he spotted a blackened bucket in the air. The worker was removing his safety harness and trying to get out of the bucket. At one point, he had his leg over the edge. "We kept yelling at him to stay," said the neighbor. The neighbor said he tore his shirt off before reaching the ground and his hair and trousers were singed. He kept asking why this had happened and worried that his ear was gone. The neighbor said he assured him his ear was there and he was going to be OK. Employee #1 suffered second-degree burns on multiple areas of his body while working from a bucket near a power line.
  29. 29. Indirect contact Fatal Nonfatal Aerial devise operator pole saw or chainsaw 2 1 cut branch 1 1 Climber Pole saw or chainsaw 17 2 Cut branch 16 4 Climbing line or lanyard 3 0 Unknown 1 0 Ground worker Pole saw 5 1 Felled tree 4 3 Ladder 3 0 Pull or tag line 3 0 Aerial device 2 1 Unknown 1 0 Unpublished data Tree Worker Fatalities (2004-2011)
  30. 30. The majority of indirect was related to failure to observe MAD by residential tree worker.
  31. 31. Employee #1 had his chain saw make contact with the energized power line, and was immediately electrocuted. Indirect contact though a saw (27%)
  32. 32. Aluminum pole pruners were involved in the majority of pole saw contact
  33. 33. Employee #1 was trimming limbs from trees. While trimming the limbs, a cut limb came into contact with a 23 KV primary overhead electric line. Employee #1 was electrocuted. Indirect contact though a branch (21%)
  34. 34. The worker in the cab started to get out to get a drink. At that moment, the lower boom hit a power line, sending electricity down to the cab, where the man who was half in, half out of the truck was shocked. The worker was initially taken to local hospital, then transferred to the burn unit at a trauma center. He lost both feet and a hand. Indirect contact though an aerial devise (3%)
  35. 35. Climbing line and lanyard WILL conduct electricity. Indirect contact though a climbing line, lanyard or pull line (4%).
  36. 36. Some incidents were due to failing to inspect for lines.
  37. 37. Failure to start with a job briefing
  38. 38. How do we compare with the rest of landscape services? Not very well and that’s a problem.
  39. 39. Within the Landscape Services Industry Industry Trans. Assa. Cont. Fall Exp Landscaping 16% 21% 5% 3% 3% Lawn care 52% 54% 20% 18% 33% Tree care 22% 12% 70% 70% 53% Others 10% 13% 5% 9% 11% Buckely, et al. 2008. Amer. J. Ind. Med. 51: 701-713
  40. 40. Events associated with work fatalities 2003-2006 Group Falls Struck-by Electrical lower falling shock levels objects All-industry 12.7% 6.3% 4.4% Landscape Services 22.6% 17.1% 9.8% Arborists 31.4% 28.9% 17.8%
  41. 41. Events associated with work fatalities 2003-2006 Group Fatal incident rate/100,000FTE All industry 3.4 Landscape Services 16.2 Arborists 58.2
  42. 42. Stay Safe! Thank You!

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