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An Update on Selected Toxic Gases in Industry

An Update on Selected Toxic Gases in Industry. Stephen W. Borron, MD, MS, FACEP, FACMT Juan C. Arias, MD South Texas Poison Center San Antonio, TX. Acknowledgments and Conflicts of Interest.

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An Update on Selected Toxic Gases in Industry

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  1. An Update on Selected Toxic Gases in Industry Stephen W. Borron, MD, MS, FACEP, FACMT Juan C. Arias, MD South Texas Poison Center San Antonio, TX

  2. Acknowledgments and Conflicts of Interest • Some material in this presentation was kindly supplied by Dr. Patrick Conner and the American Chemistry Council (Diller Registry on Phosgene Effects) • The presenter has received research funding and consulting fees from the manufacturer and distributers of hydroxocobalamin, a cyanide antidote

  3. Overview • Overview of occupational gas exposures and injuries • Epidemiology • Sources and use • Clinical case presentations • Update on treatments • Carbon monoxide • Hydrogen sulfide • Hydrogen cyanide • Phosgene • Arsine

  4. Nonfatal Occupational deaths & injuries Fatal Work injuries = 5,703 = 3.9/100,000 workers Deaths from exposure to harmful substances or environments = 525 (9%) Deaths from inhalation of substances = 58 (11% of exposure deaths, 1% of deaths) Nonfatal exposures to chemicals = 18,230 Inhalation = 5, 180 Confined spaces = 920 54 of 525 deaths due to exposures U.S. 2006 Bureau of Labor Statistics

  5. Top 10 reasons it may not pay to show up for work… Valent 2002 Chest 121;969-975

  6. Carbon monoxide

  7. Carbon monoxide • General epidemiology • 15,000 ED visits/yr for unintentional, non-fire-related CO • 500 deaths • Mostly men (3/4) • 15 yrs and above • Attributed to working with fuel-powered tools / appliances U.S. Centers for Disease Control

  8. Carbon monoxide • Occupational epidemiology • Study of 1992-1996 • 148 occupational CO unintentional deaths • Services industries (25%) • Manufacturing (14%) • Construction (14%) • Agriculture (14%) • Majority involved motor vehicle exhaust Janicak 1998 Compens Work Condition Fall;26-28

  9. Carbon monoxide • Epidemiology • AAPCC 2006 • 48 fatal CO exposures (alone/combination); • 14 fatal occupational CO exposures • 29% of all CO deaths • 58% of 24 total occupational fatalities • Occupational exposures comprise 1.5% of NPDS Bronstein 2007 Clin Toxicol 45;815-917

  10. Carbon monoxide • Epidemiology • 1989-2004: 68 incidents of CO poisoning in hotels • 772 accidentally poisoned: 711 guests, 41 employees or owners, and 20 rescue personnel (8% occupational). • 27 died, 66 had confirmed sequelae, 6 had sequelae resulting in a jury verdict • Faulty room heating caused 45 incidents, pool/spa boilers 16, CO entrained from outdoors 5 • Public verdicts averaged $4.8 million per incident • Poisonings occurred at hotels of all classes YOU CAN CHECK OUT ANY TIME YOU LIKE, BUT YOU CAN NEVER LEAVE… Weaver 2007 Am J Prev Med 33;23-27

  11. Carbon monoxide • Epidemiology • 167 patients treated for CO poisoning during hurricanes of 2004 in Florida • Portable gas-powered generators responsible in nearly all non-fatal and all fatal poisonings • 48% of generators were outside the home • 33% in the garage • 15% inside the home • 3% occurred at businesses • US Consumer Product Safety Commission estimates a typical • 5-kilowatt generator generates a concentration of CO equivalent to the tailpipe emissions of between 252 and 572 idling vehicles Van Sickle 2007 Am J Prev Med 32;340-346

  12. Carbon monoxide • Case scenario • 23 y/o commercial coffee roaster entered a 2 x 2.7 meter storage tank to retrieve a tool • He lost consciousness, retrieved 40 mins later, dead • 5 coworkers sent to hospital • 3 had lost consciousness, 2 were presyncopal • All rescuers recovered, but 1 hospitalized • Maximum CO concentrations up to 100,000 ppm Nishimura 2003 JAMA 290;334

  13. Carbon monoxide What is and what isn’t 150 children with “CO poisoning” Categorized according to source of CO Dramatic differences in signs / symptoms and outcomes with almost no difference in COHb% Chou 2000 Pediatr Emerg Care 16;151-155

  14. Carbon monoxide Treatment: HBO – The intergalactic battle rages on… Buckley 2005 Conflicting evidence regarding efficacy Evidence of bias in studies Firm guidelines cannot be established More research is needed to define the role…ifany…of HBO Bentur 2005 This review [cannot] dispel the current disagreement Brent 2005 HBOT best reserved for selected patients Seger 2005 I don’t know Buckley 2005 Toxicol Rev 24;75-92

  15. Carbon monoxide • Treatment failures…or not • CO poisoned patients may be successfully used as donors • Bentley 2001 Ann Thorac Surg 71;1194-1197 • Two hearts • Luckraz 2001 Ann Thorac Surg 72:709 –13 • Six hearts, one lung • One organ failure at 12h  death

  16. H—S—H Hydrogen sulfide

  17. Hydrogen sulfide • Product of decomposition • Petroleum (sour gas) • Paper pulp industry (Kraft process) • Decomposing food & waste • Offal • Fish scrap • Manure • Sewers • Compost pits

  18. Hydrogen sulfide • Sources and uses • Intermediate in production: • Elemental sulfur • Sodium sulfide • Other inorganic sulfides • Sulfuric acid • Extreme pressure lubricants and cutting oils

  19. Hydrogen sulfide • Epidemiology • AAPCC 2006 • 5 occupational deaths due to H2S alone or in combination out of 8 total deaths (62.5%) • 344 (all causes) treated in HCF with 10 moderate and 1 lethal outcome as single agent • Valent 2002 • #2 cause of fatal inhalational occupational injuries • Responsible for 9.7% of these deaths Bronstein 2007 Clin Toxicol 45;815-917 Valent 2002 Chest 121;969-975

  20. Hydrogen sulfide • Epidemiology • Review of 77 deaths related to manure storage over a 30 year period: 1975-2004 • 34% died while doing repair or maintenance of manure handling equipment • 22% died while trying to effect a rescue • 21% involved persons <16 years of age • Confined space entry identified as a particular risk Beaver 2007 J Agromedicine 12;3-23

  21. Hydrogen sulfide • Case scenario • 16 y/o male sent to clean a reoxygenation tank in a fish hatchery known to be contaminated with H2S after it is drained and the smell dissipates • As he begins to clean out the sludge in the 5 m deep tank he collapses. His adult co-worker attempts to rescue him and dies • EMS administers oxygen and the youth awakens • He survives intact after prolonged hospitalization and rehabilitation Nikkanen 2004 Pediatrics 113;927-929

  22. Hydrogen sulfide • Treatment • Not much new • Nitrite treatment (induction of methemoglobinemia?) remains controversial • HBO therapy…well, you can guess • Hydroxocobalamin? • Shown to form sulfitocobalamin with H2S • Clinical significance remains unknown Farquharson 1977 Am J Clin Nutr 30;1617-1622

  23. Hydrogen cyanide

  24. Hydrogen cyanide • Epidemiology • AAPCC 2006 • 0 pure HCN gas fatalities • 7 non-gas (cyanide salts) fatalities, all ingestions, none occupational • 118 unintentional exposures, 5 major outcomes • Valent 2002 • Fire smoke is the 6th most common cause of occupational inhalational fatal injuries accounting for 4% of those deaths Bronstein 2007 Clin Toxicol 45;815-917 Valent 2002 Chest 121;969-975

  25. Hydrogen cyanide • Sources and uses • 1.5 million tonnes / yr used worldwide • Vast majority used for manufacture of methyl methacrylate (plexiglas) and adiponitrile ( nylon) • Other nitrile manufacture (acrylonitrile) • Gold and silver extraction, electroplating • Jewelry cleaning • Vermin extermination • Fire smoke Cummings 2004 Occup Med 54;82-85

  26. Hydrogen cyanide • Case scenario • 25-year-old male electroplater entered a metal plating holding tank for excess zinc cyanide to clean it • Holding tank had been emptied by a waste disposal company, but had 2” zinc cyanide sludge • The victim manually pumped in between 1 and 2 gallons of 1% muriatic acid, then climbed into tank without respiratory protection • 4 minutes later, he collapsed http://www.cdc.gov/niosh/face/In-house/full8833.html

  27. Hydrogen cyanide • Case scenario, cont’d. • 4 coworkers entered the tank to attempt to rescue the victim, none had respiratory protection; all collapsed • Additional workers tried to attempt rescue; one was able to rescue one of the 4 coworkers and administer CPR • 5 workers died • 17 police officers and firefighters received toxic exposures; 30 total victims were treated http://www.cdc.gov/niosh/face/In-house/full8833.html

  28. Hydrogen cyanide • Treatment • ECETOC is currently studying cyanide antidotes to determine the most appropriate one(s) for industry, several EAPCCT members on Task Force • Hydroxocobalamin has recently been approved by the EMEA and US FDA • Cobinamide and various prodrugs of 3-mercaptopyruvate are undergoing advanced studies in the US Broderick 2006 Exp Biol Med 231;641-651 Nagasawa 2007 J Med Chem 50;6462-6464

  29. Phosgene

  30. Phosgene • Sources and uses • A high production volume chemical (OECD) • Phosgene is used in manufacture of: • Polymeric isocyanates (polyurethane, resins) • Polycarbonates (plastics) • Carbamates and related pesticides • Aniline dyes • Perfumes • Pharmaceuticals • Heating of chlorinated hydrocarbons

  31. Phosgene • Epidemiology • AAPCC 2006 • No phosgene exposures reported • Diller registry (American Chemistry Council) • Deleted from Wikitox slide set • Permission not requested or obtained for web publication • See ACC website for more information Bronstein 2007 Clin Toxicol 45;815-917

  32. Phosgene • Case scenario • 43 y/o male helping demolish a refrigeration plant • Cut through a pipe containing chlorodifluoromethane, noted a musty smell • Immediate lacrimation, cough, burning in throat • Later, dyspnea and chest pain • Admitted to hospital x 24h • Slow recovery, with lethargy, exertional dyspnea • Return to work at 2 weeks Wyatt 1995 J Accid Emerg Med 12;212-213

  33. Phosgene • Pathophysiology • Acylation • Reaction with amino, hydroxyl, and sulfhydryl groups • Denaturation of proteins and lipoids • Irreversible alterations of membrane structures • Disruption of enzyme and other cell functions • Hydrolysis • Less important: formation of HCl Borak 2000 J Occup Environ Med 43;110-119

  34. Phosgene • Treatment • Steroid • Inhalers • Prednisolone 250 mg IV • Ibuprofen • 25-50 mg/kg • N-acetylcysteine • 20 mL of a 20% NAC solution administered by nebulizer • Positive airway pressure ventilation • Rest and observation Borak 2000 J Occup Environ Med 43;110-119

  35. H As H H Arsine

  36. Arsine • Sources and uses • Production of gallium arsenide • Dopant in solid-state electronics • Manufacture of LEDs • Product of chemical reaction of arsenic salts with strong mineral acids • Metal smelting and refining • Arsenical pesticide use • Battery manufacture • Art restoration

  37. Arsine • Epidemiology • AAPCC 2006 • No arsine exposures reported • 1 arsenic death due to ingestion • Pullen-James 2006 • Approximately 750 reported exposures • 1/3 lethal Bronstein 2007 Clin Toxicol 45;815-917 Pullen-James 2006 J Natl Med Assoc 98;1998-2001

  38. Arsine • Case scenario • 55 y/o male c/o flank pain radiating into groin for two hours, with weakness, followed by gross hematuria • PMH of testicular cancer • Developed hypotension during CT to rule out stone, required vasopressors • WBC 36k, CPK 546, UA with WBC, 6-8 rbc/hpf, Cr 1.0 • Admitted to ICU with dx of sepsis Pullen-James 2006 J Natl Med Assoc 98;1998-2001

  39. Arsine • Case scenario, cont’d • Deteriorated overnight, developed ARDS • Skin became beet red, urine black, WBC increased to 43,000, Hb dropped from 11.2 to 8.8 mg/dl, Creatinine increased to 2.6 (229.8 μmol/l) • Occupational history taken on day 2: • Water detoxification plant • Removing As from water using an acid preparation • Recalled smelling garlicky odor above water • 2 coworkers presented shortly after with hematuria Pullen-James 2006 J Natl Med Assoc 98;1998-2001

  40. Arsine • Signs and symptoms of poisoning • Concentration-dependent symptom delay • Headache, vomiting, chills, dyspnea • Pain in chest, lumbar area, abdomen • Fever, tachypnea • Oliguria  anuria • Dark urine, skin tone  jaundice at 24-48h • Leukocytosis, Heinz bodies, basophilic stippling , anemia • Hyperkalemia • Ur As > 200 mcg/l

  41. Arsine • Pathophysiology • Uncertain – definitely involves O2Hb • COHb is protected • Oxidation of red blood cells resulting in massive hemolysis • Sodium-potassium pump poisoning • Swelling of RBC • Renal injury due to hemolysis, direct toxicity

  42. Arsine • Treatment • Supportive care • Plasma exchange • Antidotes for As not indicated • Exchange transfusion • Hemodialysis • Bicarbonate for hemolysis • Glutathione (?) • Dexamethasone (?) Pullen-James 2006 N Natl Med Assoc 98;1998-2001 Song 2007 Clin Toxicol 45;721-727

  43. Arsine • Treatment by plasma exchange Song 2007 Clin Toxicol 45;721-727

  44. Summary • Toxic gases continue to cause lethal and injuries in industry • These exposures account for a small percentage of fatal occupational injuries • Confined space exposures and unprotected rescue attempts result in many injuries and deaths • Treatments continue to slowly evolve and improve

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