I recently found this while looking for parts. Has anyone started to stock up on these yet?
"NOTICE TO OWNERS OF GAS FIREPLACES 10YRS OLD: MERCURY FLAME SAFETY SWITCH NO-LONGER PRODUCED! Look in the bottom door of your fireplace for this part. The Mercury Flame Safety Switch has a distinct white oval shaped porcelain head. This part allows the pilot to stay lit and if the pilot flame goes out it closes the gas valve as a safety should. The reason for this notice is that mercury has been phased out and that part is no longer produced. The safety feature of the mercury flame switch is an integral part of your fireplace. Unfortunately there is no certified alternative to this part and when once it fails the fireplace would be inoperable. We estimate there are 150-200 Mercury Flame Safety Switches left in Ontario with over 5000+ needed in Canada. The current supply will be gone this upcoming heating season and we wanted our customers to know first. The reduction in supply and increase in demand will result in a hefty price increase for this part. If you plan to keep your fireplace we recommend you purchase a Mercury Switch soon. If you plan to replace your fireplace soon, please disregard this notice."