I took a ceramics class in high school, so I may be able to help.

First of all, the employer should provide the personal protective equipment.  I have a list of exemptions, although the respirators/dust masks are included.  Also... if it is a RESPIRATOR and not a DUST MASK, they must give you a fit test.  A respiratory protection program is always a fantastic idea.

Secondly, any dust is not good for your body.  It can clog up the lungs and keep them from distributing oxygen throughout the body.  Some dusts are flat-out toxic.  We didn't have too much dust (if any) floating around the classroom I was in.  After the clay hardens (I forget the term now), it may have a little dust that comes off on your fingers, but nothing airborne.  After they get fired for the first time,

You'll have to read the glaze labels.  As far as I know, drinking or ingesting them will make you extremely ill if it doesn't kill you, but hopefully everyone has enough sense to not drink the glaze.  Glaze basically turns to glass when heated at those extremely high temperatures.  As far as fumes go, the glazes we used had no harmful fumes while being applied to the fired piece.  I once removed some pieces that had been fired once with the glaze and experienced no bad smells, fumes, etc.  As I said before, be sure to read the glaze labels.  The only thing I didn't really like about some glazes is that they were a pain to wash off the hands and they may stain clothes (I found out the hard way...).

I'm saying this out of the small amount of experience from high school, though.  I'm no expert.  My best suggestion would be to contact your local OSHA consultation group.  Simply call (800) 321-OSHA (6742) or go to www.osha.gov.

Hope I helped!

-Justin

In General Industry (29 CFR 1910), which I'm not sure would apply to your situation, respirator regulations are tricky.

29 CFR 1910.134(a)(1) directs you to first try to eliminate the hazard with "engineering control measures (for example, eclosure or confinement of the operation, general and local ventilation, and substitution of less toxic materials)."

I would think that ventilation or less toxic materials is your best bet.  It may be cheaper in the long run, but if it can be effective, it will definitely be easier as using anything other than a "nuisance mask" which is a dust mask with only 1 strap (2 strap dust masks are considered respirators and are subject to this regulation) must be accompanied with respiratory protection programs.

As outlined by 29 CFR 1910.134(c)(1) if a respirator is required (which you will need to test for) the following is needed:

• Written Program
• Worksite-specific Procedures
• Training
• Fit Testing ($$$)
• Medical Evaluations ($$$)
• Care and Maintenance
• Written Procedures for respirator Selection
• Written Procedures for routine and emergency use

That being said, if you're still with me and not fallen over in your chair, this is what I would do:

• Refer to the MSDS for all the components that are being used/heated in this room
• If there are chemicals in any of these materials for which a PEL exists, contact your work comp insurance carrier's loss consultant and see if they will offer air monitoring for those chemicals free of charge.  Some include this service in your premium costs.
• If there are not chemicals for which a PEL exists, then stop worrying about it - you're fine.  You can use the 1 strap nuisance masks or nothing at all.
• If you end up needing air quality assessment see what the results are. 
• If they're over the PEL, ask the loss consultant for help in finding the appropriate respirator and developing the accompanying program.
• If they're not over the PEL then stop worrying about it - you're fine.  You can use the 1 strap nuisance masks or nothing at all.

It should be noted that you should always try engineering controls over PPE, if the engineering controls are not feasible document that somewhere in case it is brought into question.