From Fall 2009

**Q. I was a little confused when trying to look at respirator requirements vs. exposure limits because the respirator requirements were given in mg/m^3 and the exposure limits are (often) given in ppm.  
A. The math is not too hard, if you know the MW, molecular weight.  That’s easy for most pure substances, but some are mixtures.  Often there is a nominal MW which will serve.  The direct conversion is given in the NIOSH book and other places.  Also here:

*Q. I’m embarrassed to admit that the entire sub-module that consisted of learning about styrene….I was looking at the MSDS for styrene and not styrene monomer. Who would have guessed that there was a difference! Naturally, I got the quiz question wrong that asked for its NFPA reactivity number. Styrene is 2, the monomer is 0. I am curious- just what is a monomer? 
A. A polymer consists of many monomers attached together.  [I’ve often thought about what a “mer” is, with the “maid.”]  Wiki has a good explanation:

End Fall 09 Additions.

***Note.  REMBER the hierarchy of industrial hygiene.  FIRST, use “engineering controls.”  Eliminate the hazard.  SECOND, use “administrative controls” which generally mean eliminate or limit access to the hazard – reduce work hours or only allow people with particular training into the area. THIRDLY and LASTLY do you use PPE. 

**Q. One thing I found interesting was the protection factor index.  This seems like a handy tool to use to approximate the required respiratory protection. 
A. Yes, but it is mostly assumption.  In order to have any confidence in the protecaiton factor, you need a “respirator fit test” to assure it is achieving that.

* Q. A couple times you are talking about flammables and describe them in terms of being explosive.  I’ve never heard them used interchangeably.  Would it be safe to say then that an explosive material is always flammable, but that a flammable material is not always explosive? 
*A.I may not have used the words carefully.  “An explosive” would be a product designed to explode, like TNT.  “An explosion hazard” would be anything that can explode.  Flammable vapors are always an explosion hazard, if they are over the LEL and under the UEL.   

*Q. Under the Ventilation Section, you write Mechanical PE.  For what does “PE” stand? A. Professional Engineer – licensed by the state to design such things.  Most states license engineers by specialty and mechanical engineers are licensed to design HVAC (heating ventilation and air conditions systems). 

*Q. One question I have had with PPE is about gloves.  The NIOSH pocket guide seems to do a good job indicating the correct respirator for the chemical of interest, but a lot of gloves say protect against “most organic solvents,” such as the link.  Is there a better way to know if a glove is compatible with the solvent you are using?  I found out the hard way the acetone and nitrile are not compatible. 
A. If you know what chemicals you are working with, you should ask the glove manufacturer.  Most large manufacturers of protective equipment will not sell you something that will not work.  I gave you one site [] with information about many chemicals.  However some chemicals are not listed.  What to do?  It depends on the hazard level of the chemical.  If it is not too hazardous, you might just take your chances with a general purpose glove.  You generally know when they don’t work – then try something else.  If it is a more hazardous chemical, remember it is your employer’s obligation to supply you with the correct equipment.  Often, as a professional, you feel you have to figure it out, which means you need the time and resources to do that.  You may also call the Department of Labor, but they might not be helpful if it is not a common chemical.  If you need to use the chemical a lot and it is fairly toxic, your employer might hire a test lab to perform break though tests.  Finally, if you can’t decide between two glove materials, you can wear two sets of gloves, one inside the other.  Often the incompatibility of the chemical is due to the speed that gloves will break down.  In that case it may be the simple matter of changing your gloves each time you use the chemical – simple does not mean cheap.  Finally, I would call the manufacturer of the chemical or someone else who make it, ask to talk to their health and safety department and ask them what they use. 

*Q. Something that is a little foggy to me is the fact that most of the MSDS that I review don’t include the appropriate PPE for a given chemical.  For example, they almost always say wear gloves, but there is no indication of what type to use (compatibility issues).  Often they simply ask you to “use the appropriate gloves”.  It seems to me that listing the appropriate glove type should be standard practice.  
A. Yes, but remember the regulation only says “known [to the manufacturer].”    If they don’t know, they don’t have to invest any time or money finding out.

*Q. One question I have concerning PPE is regarding disposal.  You usually wear it to protect yourself from hazardous chemicals; however, we often dispose of it as IDW [Investigation Derived Waste].  Is this due to the de minimus amount of material on it?  I assume this varies depending on the substance it comes into contact with (i.e. radioactive material has different standards than mineral spirits).  
A. A complex question – let me think as I write.  If you are generating hazardous waste with your activities, you – the consultant or contractor- become the generator.  This is often the case in hazardous waste remediation when you dig up an old site.  But are you tyvek suits and gloves a hazardous waste?  First of all, are they RCRA waste?  Look at the listed and characteristic again.  Since they are not on a list or flammable, corrosive, or reactive, the only thing they can be is toxic, by the TCLP.  For the TCLP, you need to take an aliquot of the waste stream,, which includes the concrete, dirt, and whatever.  In the case of IDW, you would take a sample that included all the clean suits as well as, let’s say, the gloves that are contaminated.  On that basis, it would be very rare if the IDW failed the TCLP, since the contaminant would be such a small percent of the waste stream.

Q. I had no idea about the State Fire Marshals enforcement responsibility.  Given that most of Alaska is outside governing municipalities, his area of responsibility is huge.  I doubt he/she (looked him up, Gary Powell) knows half of what is going on around the bush.  I’m guessing it’s only a real excitement happens when forest fires threaten cabins or mines out in the middle of nowhere.
A. No, forest fires are the State Forestry.  Fire Marshal is concerned with public buildings, a bush school, for example, or a hotel.