"Lew Hodgett" wrote
Was told by my customer, an oil company, that if they ever had to use the
halon, the fine would be $500,000 and over $1,000,000 within 5 years.

In the US the ban is on manufacture and non emergency release of
Halons. From the EPA regs:

"(6) This prohibition does not apply to the emergency release of
Halons for the legitimate purpose of fire extinguishing, explosion
inertion, or other emergency applications for which the equipment or
systems were designed."

So if you presently possess Halon extinguishing equipment in the US,
its use is not illegal. Turns out only 18% of Halon releases were
from activated equipment, 82% was being released during testing,
maintenance and disposal of equipment.