NOTE: I just received a report that Shilshole Marina is no longer accepting flares so there may be changes in other locations below as the ones listed were all having the flares picked up by the same person. Sorry for the inconvenience.
Boaters in the Seattle area now have a safe and legal way to dispose of old safety flares. The what do I do with old flares is a recurring problem for boaters as safety flares expire 42 months from Date of Manufacture (check the expiration date when purchasing flares and every spring when you start your boating season).
Lighting flares for a non-distress reason on Federally Regulated waters is a Federal Crime. Offenders can and have gone to jail, been fined and required to pay for the cost of responding to the false mayday.
The flare collection sites are:
Elliott Bay Marina
Fisherman’s Terminal
Shilshole Bay Marina
West Marine, Shilshole Bay
Western Fire & Safety, Ballard
Seattle Police Harbor Base (North Lake Union, west of Gas Works Park)
The Seattle flare disposal program was started in 1999 by Mr. Al Jensen, U.S. Coast Guard Auxiliary member of Flotilla 12, Edmonds Washington. Al started the program after finding out that District 13 Coast Guard (Pacific North West) was spending about $ 1.3 million dollars a year responding to false flare sightings. Al collected and disposed of 2,740 flares the first year and in 2000 he received a Superior Professional Achievement Award from District 13 for saving the district almost $700,000 in reduced false flare sightings. As of spring 2009, Al had collected and safely disposed of about 20,000 flares.

Thanks mike.. I have a bunch of old flares.. Fishermans terminal.. oh gads. that is way too easy!
Thanks
Natalie