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Guidelines for Safe Handling and Use of Polymeric MDI

Nautilus. Composites LLC. Making Composites Better With Polyurethane. Guidelines for Safe Handling and Use of Polymeric MDI. Polymeric MDI - Safe Handling/Use. Isocyanates/Diisocyanates are reactive chemicals.

jileen-caffrey
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Guidelines for Safe Handling and Use of Polymeric MDI

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  1. Nautilus Composites LLC Making Composites Better With Polyurethane Guidelines for Safe Handling and Use of Polymeric MDI

  2. Polymeric MDI - Safe Handling/Use • Isocyanates/Diisocyanates are reactive chemicals. • Many specific compounds in this family of chemicals - characterized by -NCO functional groups. • Chemical/Physical properties of specific compounds vary • Used for over 40 years to make a variety of polyurethane products in home & industry. • Used since the mid 1980s in the forest products industry to make OSB.

  3. Polyurethane Products • Paints, varnishes • Automobile parts (bumpers, dashboards, headliners, armrests, seats, carpet underlayment,) • Binder for wood products (OSB, MDF, etc.) • Insulation in home appliances, buildings (roofs, walls). • Footwear, sports equipment. • Pillows, mattresses, clothing

  4. Physical Properties of PMDI/MDI • Brown liquid having consistency of motor oil. • Reacts with water for form solid polyureas and carbon dioxide. • Poor odor warning properties (odors are however subjective). • Very low vapor pressure (VP) • VP of water ~1.8 million times greater

  5. Polymeric MDI - Safe Handling /Use • Prevent exposures - prevent risk of injury • Use a combination of effective control measures • Engineering - enclosures, local exhaust ventilation • Administrative - work practices, controlled access • Personal Protective Equipment - gloves, respirators etc. • Control measures must be properly maintained for them to be effective. • Engineering - - - PPE (least preferred)

  6. Exposure Limits • Airborne concentrations of substances… • To which nearly all workers may be repeatedly exposed.. • Day after day for a working lifetime.. • Without adverse health effects.

  7. Philosophy Behind Setting Exposure Limits • Based on acceptable risk • All chemicals are toxic at some concentration • A concentration exists at which no significant injurious effect should occur

  8. Routes of Exposure to Chemicals • Inhalation - breathing the air in which the chemical is suspended • Skin and eye contact • Ingestion (least significant route of exposure)

  9. Exposure Limits - MDI • OSHA Permissible Exposure Limit (PEL) - USA • 0.2 mg/M3 = 0.020 ppm, ceiling (legally binding) • ACGIH Threshold Limit Value (TLV) - USA • 0.051 mg/M3 = 0.005 ppm, 8-hr TWA (good recommended practice) • For comparison, vapor pressure of MDI at room temperature is about 0.006 ppm, with no ventilation

  10. Effects of Overexposure - MDI • Irritation of the respiratory tract, eyes, nose • Symptoms may include sore throat, chest tightness, wheezing, coughing • Respiratory sensitization - occupational asthma • Difficulty breathing, asthmatic symptoms • Symptoms may be immediate or delayed or both • Exposure limits may not be protective • To prevent symptoms, avoid exposures • If early diagnosis, good chance of recovery; however, there are no guarantees

  11. Agents Which Can Cause Occupational Asthma • Naturally Occurring Products • Animal dander, latex proteins, insect debris, flour, tobacco dust, moldy compost, rosin(fluxes), soybean dusts, wood dusts, mushroom dusts…. • Synthetic Products • Metal salts (Ni, Cr, Pt), Persulfates, Penicillin, Tetracycline, Amines, Formaldehyde, Diisocyanates,...

  12. Effects of Overexposure - MDI • Eye Contact • Pain, irritation, possible corneal burns if not treated • Skin Contact • Brown discoloration - hardens, eventually peels off • Skin rash - prolonged, repeated contact - skin sensitization • Respiratory sensitization?? - data inconclusive - avoid skin contact • Ingestion • Irritation of digestive tract • Practically non-toxic by this route (= table salt)

  13. Air Monitoring for MDI • Direct Reading Methods - Screening • Paper tape technology - color change • Interpret results with caution • Results at best semi-quantitative • Indirect Methods • Treated filter papers or impingers • Requires laboratory analysis • Highly accurate and precise

  14. Scott Bacharach SureSpot Monitor

  15. Scott Bacharach AutoStep Plus Direct Reading Monitor

  16. Polymeric MDI - Safe Handling/Use Medical Surveillance • Medical history with emphasis on the respiratory tract • Pulmonary Function Testing (PFT) • Baseline • Periodic (if symptoms of over exposure occur) • Recommended by all suppliers of MDI/PMDI • Not required by law

  17. Personal Protective Equipment - PPE • Gloves - nitrile, butyl, or neoprene rubber • Coveralls - Tychem SL (Saranex) or Tyvek QC (PE) laminated • Respirators • Supplied-air (historically) - if airborne levels warrant use • Recent change in OSHA respirator standard • May be OK to use air-purifying respirators for some applications if certain conditions are met. • Boots - same materials as gloves • Engineering controls most preferred

  18. Personal Protective Equipment:Appropriate Use • Disposable gloves are sufficient for most production situations • Coveralls, boots and respirators typically only required when loading large storage tanks or cleaning up very large spills (more than 20 gallons)

  19. Spills • Don protective equipment • If needed, monitor to evaluate airborne levels • Contain spill with absorbent material (sand, dirt, spill kit, etc.) • Mix well and shovel into containers - move outside, do not seal • Add decon solution and mix well - let stand • Dispose of solids/liquids per State or local regulations

  20. Decontamination solutions • Type A • Water (90%) • Concentrated Ammonia (8%) • Liquid detergent (2%) • Type B • Water (90-95%) • Sodium Carbonate (5-10%) • Liquid detergent (0.2-0.5%)

  21. MDI Under Fire Conditions • Not readily ignitable (35 kg) • Heptane (1L) added to enable MDI to burn • Mass burned for several minutes after ignition • Fire subsided, then ceased leaving behind a dark residue ~80% of original sample weight. • Offgassing products - CO2 (47%); CO (180 ppm): Nox (30 ppm); HCN (15 ppm); MDI (1.8 ppm) • Concern for responders - use same PPE as for typical structural fires

  22. Comparison: Gaseous Combustion Products of Untreated and Treated Wood (mg/g)

  23. Re-evaluation of Diisocyanates Data for Cancer Classification - IARC • Status of TDI and MDI reviewed in 1998 • Data made available for both • Human evidence inadequate to change classification for TDI - remains category 2B - possibly carcinogenic to humans. • Insufficient new data available to warrant a full scale review for MDI - remains category 3 - not classifiable as to carcinogenicity to humans.

  24. IARC Classification Scheme for Cancer • Category 1: Sufficient evidence of cancer in humans - asbestos, wood dust, VC • Category 2: probably carcinogenic to humans • 2A - Limited evidence to humans: Be, acrylonitrile, • 2B - Sufficient evidence in animals, inadequate data in humans - Cd, DDT, TDI, formaldehyde, • Category 3: not classifiable as to carcinogenicity to humans - Cyclamates, Saccharin, MDI,

  25. Environmental Issues • MDI is listed as a Hazardous Air Pollutant (HAP) • MDI invalidated by court of appeals as a high risk pollutant under the US Clean Air Act. • MDI removed from EPA’s Urban Toxics listing of chemicals presenting the “greatest threat to public health”. • Overestimated emissions reporting by industries • Improper assumptions in calculating emissions by consultants. • Petition filed in 8/98 with EPA to exempt MDI as a VOC - inhibits ozone formation (CA study).

  26. Environmental Fate of MDI* • The half-life of MDI is short (0.6 - 32 hours) and will have a limited tendency to accumulate in environment due to air emissions. • Spills are not likely to release MDI in either vapor or aerosol form; therefore, significant airborne levels are not expected. • The reactions that occur after spills (solids and water insoluble polyureas) limit further exposure to airborne MDI. • * Manitoba Environment, Report 96-08

  27. Polyol Formulations • High molecular weight polyester and polyether polyols - major component • Generally regarded as non-toxic and non-hazardous • Catalysts and mold release agents - minor component in polyol formulation (0.1- 5% typically) • Occasionally caustic (irritants, corrosives, skin absorption for some but not many • Occasionally odorous • Use local exhaust ventilation and PPE to prevent exposure, if indicated by MSDS

  28. The Bottom Line: • Use common sense when handling all kinds of chemicals. Maintain a sense of perspective. • All chemicals have some degree of toxicity. • Any chemical is toxic if the amount consumed (dose) is large enough. • People drown in water, suffocate in pure nitrogen • Toxicity and hazard are not the same • Toxicity - ability to cause damage in living systems • Hazard - risk/likelihood of injury - depends on how used • Exposure doesn’t necessarily mean harm - depends on dose.

  29. The Bottom Line: • Benefits are provided by end products made from isocyanates/diisocyanates. • There are risks associated with any activities we undertake • Handling/using chemicals - no exception • All chemicals can produce adverse health effects and be hazardous - depends on how they are handled/used. • Risk of injury can be real or perceived. • Risk is minimized or eliminated when chemicals are properly handled.

  30. For further information, contact… Harry D. Coffee Nautilus Composites LLC 575 Walnut Ridge Trail Aurora, OH 44202 (330) 995-2636 office (216) 496-8921 cell hdcoffee@adelphia.net

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