im in the process of preparing an enviromental report highlighting the differences between the construction of an array of different types of boards, in regard to there hazards , solvent release and the emissions of toxins into the atmosphere and dangers to workers , what i found out about our standard clark blank which uses toulene di-isocyanate as the main ingredient shocked me …
please read …
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[ 3]Conventional urethane foam in surfboards is 6% solid ,uses a combination of toluene di-isocyanate and carbon dioxide , carbon dioxide has replaced some of the cfc’s used in the past, the use of TDI is mainly for its crisp white looks , but the trade off is the release of cyanide gas and carbon dioxide during expansion , not all the gas fully escapes the closed cell , which means when urethane foam is machined traces of cyanide gas are still given off .[/]
Following is some information on urethane foam and its dangers .
HAZARD DATA SHEET
URETHANE RESIN SYSTEMS
Monona Rossol, Health and Safety Officer for
United Scenic Artists, Local USA-829, IATSE
October 10, 1995
212/777-0062 or e-mail
75054.2542@compuserv. com
STRAIGHT TALK ABOUT URETHANE FOAM AND CASTING RESINS
“The resin part of a urethane product is not very hazardous. This is because it is not actually a “urethane resin.” Instead, it is any of several types of resins such as polyesters, polyethers, polyols, epoxies, and so on. These resins do not become “polyurethane” until they are reacted (cured, hardened, etc. ) with a diisocyanate. These diisocyanates are the problem.
Diisocyanate hardeners are capable of causing severe respiratory allergies and lung damage. Most notably, they cause a debilitating incurable occupational illness called “isocyanate asthma.” Sudden respiratory spasms and anaphylactic shock on exposure to diisocyanates also has resulted in death among workers using urethanes. There have been cases in which deaths occurred suddenly and without warning in people with no prior history of allergies.
To protect people from these effects, the American Conference of Governmental Industrial Hygienists set and extremely restrictive workplace air quality limit (Threshold Limit Value or TLV) for diisocyanates. To see just how incredibly restrictive (low) the TLV for diisocyanate is, the table on the following page compares it with TLVs for other substances.
TLVs OF VARIOUS CHEMICAL.S COMPARED TO DIISOCYANATES
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Substance Threshold Limit Values in parts per million
ethyl alcohol 1000.
rubbing alcohol 400.
mineral spirits 100.
toluene 50.
carbon tetrachloride 5.
phosgene (war gas) 0.1
methyl isocyanatel 0.02
diisocyanates** 0.005
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* This is the chemical that killed thousands of people in an accident in Bhopal, India
** The following are the diisocyanates which have been studied enough to set the 0.005 ppm TLV
-TDI (toluene diisocyanate), CAS # 584-84-9
-MDI (methylene bisphenyl isocyanate), CAS # 101-68-8
-hexamethylene diisocyanate, CAS # 82-06-0
-isophorone diisocyanate, CAS # 4098-71-9
-methylene bis(4-cyclohexylisocyanate),CAS # 5124-30-1
HOW DO I KNOW DIISOCYANATES ARE IN MY STUFF?
You can identify urethane curing agents by reading the product’s material safety data sheet (MSDS). Look for the words “diisocyanate” or “isocyanate” listed under “chemical family” or as part of a chemical name under the “hazardous ingredients” section. The Table above lists five of the names you may encounter.
Some of the MSDSs and product labels will provide stern warnings about the dangers of the diisocyanates. Others will not. The products without strong warnings usually contain one of the forty or more isocyanates for which no standards exist. This does not mean that these diisocyanates are safe. It means they have not been tested and proved toxic. It also means that the manufacturer is taking advantage of a flaw in the labeling law that allows untested chemicals to be considered “innocent.”
Yet ALL the diisocyanates are hazardous as EPA made clear in 1994
… EPA believes that it is reasonable to anticipate that all members of the diisocyanate category will exhibit chronic pulmonary toxicity …
Only one of the diisocyanates (toluene diisocyanate - TDI) has been studied for long term hazards and it has been found to cause cancer in test animals.’ The other diisocyanates have not been tested so manufacturers are not required to warn users about this possibility either. In fact, the MSDSs will probably say that OSHA, IARC, and NTP do not consider them carcinogens. It would be fairer for the manufacturer to tell you that these three agencies have never evaluated their isocyanate, and further, that the isocyanate is in the same class as a chemical that does cause cancer.
SALESPEOPLE TELL ME THAT THEIR PRODUCT IS 'DIFFERENT"
Manufacturers can change diisocyanates into unregulated chemicals by linking several of them together (prepolymerizing) or by modifying them by adding various groups of elements. These altered diisocyanates are often touted as “different” and “safe.” In some cases, these altered diisocyanate molecules are heavier so less of them get into the air where they can be breathed. However, the levels at which they are hazardous is so low that this should not be relied upon for safety.
WHAT STEPS SHOULD I TAKE WITH URETHANE PRODUCTS?
If you are considering using a resin product that might contain an isocyanate, take the following steps.
1 ) Find out if the product is a resin system consisting of two or more components. Consult product literature to determine if the product requires mixing either by hand or that mixing occurs when the product is extruded by the container.
(Single-component urethane varnishes and paints are not as hazardous and usually contain only traces of isocyanates.)
2) Look on the MSDS for the words "isocyanatell or "diisocyanate. "
3) If the product contains an iso- or diisocyanate, ignore any claims that it is “prepolymerized”, modified, or safe in any way. If you need to have the particular chemicals in your product looked up, call your Health and Safety Officer.
4) Try to find a safer substitute for the product.
5) If the product must be used, work in a local exhaust system such as a spray booth. If the exhaust system cannot provide 100 % protection, use air-supplied respiratory protection as back-up. The SCBA or airline equipment is required because there are no air-purifying respirator cartridges approved for the isocyanates.
6) Leave freshly cast or foamed objects in the exhaust system for several hours or over night until they have completely set up and have finished off-gassing before taking them into the general workspace.
7) Never burn or heat finished urethane objects until they begin to discolor, smoke, or decompose except in local exhaust ventilation. Heat releases many toxic gases and vapors including some isocyanate.”
how did you like that one ??
it just gets better …
regards
BERT[/]
