Fire extinguishers

From BMWCCA club racing rules:

Each team that refuels must have a fireman with a fire extinguisher with a minimum nominal capacity of 10 pounds and a minimum UL rating of 60B:C.

NASA enduro rules:
All  competitors  are  required  to  keep  two  gallons  of  water,  at  least  one  5  lb.  or  larger  ABC  rated  fire extinguisher  (with  a  gauge  indicating  fully  charged),  and  at  least  5  pounds  of  oil  absorbent  in  their  pit space.   

If your refueling fire bottle meets or exceeds the BMWCCA rule above, you should be fine just about everywhere.

EDIT:  Looks like a 10lb 60B:C is under $50 shipped.
http://www.google.com/products?hl=en&am … ;scoring=p

For what its worth, It took a Lemons race to realize that a 2.5lb bottle in the garage will be horribly undersized if something goes wrong while working on my car.  I now have a 10lb dry chem bottle and a giant CO2 bottle at home.  The CO2 bottle was an expired unit from a friend's business.  They decided to replace all their CO2 units rather than recertify.  The gauge is in the green so I think its fine for home use.