From Mythago's blog.
Why you should prepare your witness for cross-examination:
Q. So did you ever try to contact any of the people who used your product, to see if they had become ill?
A. No, we didn't really deal with the tradesmen. We mostly sold to distributors.
Q. So that's a "no"?
A. That's a no.
Q. If you wanted to try to reach these guys, how would you go about it?
A. I don't know.
Q. Would contacting [this trade's local union] be a good place to start?
Q. Did you ever give the union a call?
A. No. That would probably just lead to a whole bunch more lawsuits.