The Patent Act of 2005
stevelaniel writes "The Patent Act of 2005 has been proposed, and at least one law professor has described it as "a surprisingly broad proposal to reform patent law. Among other significant changes, it proposes to scrap the first to invent standard in favor of a first to file standard. Other notables include imposing a rigorous duty of candor on applicants, limits on damages/injunctions and new standards for anticipating prior art." The Promote The Progress weblog is compiling source documents on the Act."
This is designed to clear the PTO's backlog, nothing more.
If you have been doing it in a non-secret way, their "invention" is not new and they should not get a patent. Your product is prior art.
However, if it's a part of your secret production processes... In many countries you would then be allowed to continue as before but you would lose the ability to sell the technology as their patent would cover all other use.
IAAAL - I am actually a lawyer
Look up interference practice in the MPEP sometime.
"I have a porkchop, you have a porkchop. I have a veal, you have a veal".