Instructions
Contact your local solid waste management department. Some have drop-off sites or yearly collection times for hazardous materials. Some counties accept flares if you are a resident of that county.
Ignite the flares in a safe area on land. Check with the local police and fire departments first for their guidance. They might have additional information or know of local collection programs.
Contact the Coast Guard Auxiliary or Power Squadron. See if they are interested in taking them. They can use expired flares for demonstrations and training activities.