You are so right about keeping clay dust to a minimum...clay dust in the
lungs on a regular basis (who knows how much, really) causes a permanent
lung disease called silicosis. Wash your tools each time, scrape and
clean your bats and potters wheels, and demand that your floors get
washed every night. Your janitor should damp sweep and wear a mask to
protect his/her health if you do clay in your room on a regular basis.
Tell your kids about the health risks. My kids clean REALLY well each
time because they know about silicosis and how to prevent it. LIke so
many art risks, if you know how to use your materials safely, there is
nothing to worry about. It's the DUST that gets you, as well as using
non food safe glazes on dinnerware/drinking vessels, handling raw
materials or glazes with dangerous raw materials. Read the labels on
your glazes and KNOW what you are buying and using with your students.