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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 varyUsed for over 40 years to make a variety of polyurethane products in home
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1. 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