CHEMICAL TOXICITY

The information below was posted on the Fine Scale Modeler's Forum on March 29, 2004 by Gip Winecoff in response to a question pertaining to the toxicity of acrylic paints.  Gip is an Industrial Hygienist and when he talks about the affects of modeling chemicals on our health I tend to listen closely.  His response has been reprinted here with his permission

Just thought I'd chime in...

An old Greek dude named Paracelsus once said that everything is toxic; it all depends on the dose.  Exposure is based upon two basic factors, the frequency (how often) and duration (how long) of the task.  Other factors are also considered contributory; they include such things as ingredients and concentration of the material you're working with, how much is in use, how it's being used (brushing vs. spraying), distance from the source, available controls such as ventilation or barriers, and any protective devices in use, such as a respirator.  There are other considerations as well such as personal susceptibilities (like multiple chemical senstitivity), or propensities toward such things as allergies, or even pre-existing medical conditions such as asthma.

All of the posts in this thread have pretty much nailed the topic discussion.  Basically, even though a material may be not be considered toxic or hazardous, caution should still be exercised and proper procedures followed for how the material should be used to avoid the potential for overexposures to occur. One of the most misleading things I have ever seen are the words "environmentally safe".  Simply because a material is safe for the environment doesn't necessarily mean it's non-hazardous to humans.  I have seen individuals overcome by environmentally safe organic vapors, and have to be taken to local clinics for observation.  And the label also said the material was flammable...

Be careful with acrylics.  While their RELATIVE hazards may be somewhat less than enamels (and then there are acrylic enamels), many contain alcohols and others may contain certain glycol ethers or possibly their associated acetates.  Alcohols are toxic in their own right.  OSHA has established a 15 min. short term exposure limit (STEL) for both isopropyl alcohol and methyl alcohol (methanol).  And both are flammable.  BTW, the flames from alcohol fires are practically invisible, so be overly careful.  Glycol ethers and ether acetates can affect the hematopoietic (blood-based) systems of the body.  (In addition, be wary of the ingredients in pigments, particularly the interior greens, zinc chromates, and some yellows used in the aircraft line of paints.  I admit not having seen any MSDSs from model paint companies, but until I know for certain I will assume any of these materials to contain chrome-based pigments and take appropriate precautions.  Zinc chromate as well as other hexavalent chrome compounds (Cr +6) are now confirmed human carcinogens (lung).

Above all, remember that the use of common sense is authorized.  Typically, we in the modeling community spray (I use spray since that tends to typically carry the highest hazard potential) in very small quantities for fairly limited periods of time at any sitting.  IMHO, I think that our overall potential for overexposures (that amount that exceeds the body's ability to metabolize and detoxify) is minimal.

I do, however, think that all bets are off when you pull out the spray can for that 1/16 King Big Track, or that 1/192 USS Neversail-but that's another thread...

I've pretty much rambled here. Hope this helps someone.[:)] Gip Winecoff

For those who would like to read the entire thread it can be found at This Link



I would also like to include this information that Gip posted in response to a question pertaining to glues and adhesives because it also has some very good information about toxicity.  While Gip didn't explicitly give me permission to repeat this information I don't think he will object.

Hi, Jesse! Congrats on being a parent.

A couple of things:

Toxicity is based, in large part, on exposure to a substance (the dose).  How often you perform a task, how long it lasts, the materials used (incuding conentration and chemical characteristics), and environmental conditions (i.e., available ventilation, etc.) all factor in to determine how much of a dose is received by the body.  The dose received and the body's ability to effectively metabolize any potential toxicants determine overall toxicity.  It's also important to realize that materials such as acrylic paints are only RELATIVELY less toxic than enamels.  Brush painting is going to result in less dose received than if you are spraying; however, both acrylics and enamels contain organic solvents that are going to become airborne and present a potential inhalation hazard.  While acrylics may not contain the faster evaporating solvents like xylene or toluene (as found in enamels and lacquers), they may contain alcohols and glycol ethers, that when inhaled present the same basic toxicity hazards as enamels.  So don't throw that respirator away just yet!  In addition, pigments from paints can also be hazardous.  While most manufacturers have gotten rid of pigments containing heavy metals (cadmium and lead), chromium (including the carcinogenic zinc chromate) may still be used in some applications.  Spraying these products may cause pigment to settle on some horizontal surfaces.  If your daughter begins chewing on these surfaces (e.g., during teething), then there is a risk of exposure to her via ingestion.

As far as gluing is concerned, there are "non-toxic" glues available (Testors, I think), but their ability to hold parts together effectively is somewhat diminished.  This is one of those frequency/duration tasks where I don't think a great deal of exposure is going to occur.  For example, two nights ago I glued a 1/48 fuselage together and may have used 15-20 drops over a period of 5-10 minutes (actual glue time).  I would consider my own exposure minimal, even though my nose was near the work task in progress.  I use Tamiya extra thin, which contains butyl acetate and acetone, two solvents that are much less toxic than, say, Ambroid or Tenax that contain methylene chloride (a carcinogen).  Testors liquid cement contains methyl ethyl ketone, another relatively safe solvent.  Insofar as your daughter is concerned, I would consider her exposure minimal, unless her proximity to you during this task is very close.

As far as putties go, I don't personally know of any considered non-toxic.

There are some things you can do to minimize potential exposures:

  1. Keep caps and lids on paints and glues when you are not using them.
  2. Use minimal amounts-only the amounts necessary to complete the task at hand.
  3. Don't toss rags or paper products containing solvent-based materials in the trash can in your hobby room.  Get up and throw them someplace where vapor concentrations won't accumulate.
  4. Don't spray paint during your daughter's time in the room with you.  For her safety and yours, consideration should be given to obtaining a spray booth.  If a spray booth is not yet feasible, make sure you perform a wipe-down of all surfaces in the room that she might come into contact with during her play time.  For your own safety, open a window and get some air movement going in the room.  Better yet, don't spray in the house.  Take your work outside, in the garage, or over at your neighbors house.
  5. When gluing or puttying, keep a small fan blowing across you breathing zone to both disperse and dilute vapors being generated.  Crack a window to allow some fresh air to come in
  6. If you have a spill, clean it up immediately, and refer to no. 3 above.  Get some air movement going to disperse vapors.
  7. While not toxicity-oriented, it may be a good idea to keep a fire extinguisher handy, just in case....
Remember that it doesn't take as much dose for your daughter as it does for you to reach some level of toxicity in her system; however, given the frequencies and durations of the work tasks performed during modeling and her location relative to yours during those tasks, eposures should be minimal, except for spray painting.

I apologize for rambling.  I have about 100 more things to say, and I know I've missed several things I should have said.  If you have any questions, please feel free to shoot me an e-mail.  I know there will be good suggestions from others on this forum, as well.

Hope this helps.

All the best to your new family!

For those who would like to read the entire thread it can be found at This Link"



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