The Real Club Náutico Calpe (RCNC) have advised that, in Spain, the seller of flares is responsible for safely disposing of them but most of them do not do it because the Spanish legislation is not very clear. However, there are some marinas and clubs that provide this service.

The Salvamiento Maritimo advise that the purchaser of the product at the time of expiration date is responsible for ensuring that the supplier of the flares (manufacturer, importer or distributor) collects the expired products from the end consumer for correct disposal. They also state that the provisions of Annex V of the International Convention for the Prevention of Pollution from Ships (Marpol Convention) must be followed.

We are reliably informed that fire stations (Bomberos) accept them, but this is not confirmed.
For UK-based yachts, see the RYA guidelines on this subject by clicking HERE
Samir Chami
CBYA Safety Officer