I have been thinking of casting my own round balls.
James, if you haven't read it yet, here's part of an article (PDF) titled "Lead Safety" from the Los Angeles Silhouette Club, recommended by 64Springer:
3. Why casting in the house is a bad idea:
A. Soft floors suck up lead dust and hold it forever
B. People eat all over the house
C. Ventilation typically blows dust all over the house.
D. Ventilation not really setup to pull out smoke.
E. Kids and pets don't watch what goes in the mouth.
F. Your Smelting/Casting Area: Lead dust and fumes are the problem. Lots of ventilation is your friend. This means "Up and Out" with a good ventilation fan that blows the air outside...
Blowing the lead oxide dust *Around* (box or desk fan) is just as bad as poor ventilation.
Even with good ventilation, you still have a 100% chance of lead dust getting on everything in your "Lead Area" -- especially the floor. Lead is the heaviest non-radioactive naturally occurring element. Lead oxide is heavier than Iron, but is extremely fine powder -- like baby powder. It hits the floor *Very*quickly and looks like a fine yellowish/brown dust.