FYI, since I just finished researching this until my eyes bled.
(my mother's best friend suffered a massive brain injury and I'm a bit paranoid regarding helmet safety!)
I have come to the conclusion through a lot of research (since neither in the US nor Canada has helmets specifically designed for recreational ice skating or figure skating), that the safest option is not actually a hockey helmet, but a dual certified cycling/skating/skateboarding helmet. A hockey helmet might do the job, but a regular skating helmet would probably be better, and a dual certified would be ideal. A hockey helmet is not designed for a single high impact, but rather, multiple smaller impacts - such as a puck to the head, crashing/being checked into the boards, etc - granted it will also offer *some* protection against a fall on the ice but not nearly as well as a trick skateboarding helmet (a hockey helmet will only protect against a fall from 1 meter, vs. the foam in a cycling helmet which protects from 2 meters (important if you fall during a jump, which hockey players do not do). Hockey helmets are just not designed for the type of high impact crash that may occur during figure skating. The dual certified nature is needed for skating because although the foam in a cycling helmet offers better high impact protection, it offers little to no protection at the back of the head)
The best helmet is actually a dual-certified multi-sport cycling/skateboarding helmet - certified to both the CPSC bike standard AND the ASTM F1492 trick skateboarding standard. This provides protection for the back of the head, provides smaller, multi-impact protection PLUS the higher impact protection of a cycling helmet (helmet should be replaced after ONE high impact).
You have to be careful purchasing a multi-sport or skateboarding helmet, however - as skateboarding helmets are not *legally* regulated. The ASTM F1492 sticker must be on the inside of the helmet in order for it to meet those standards. You will often see multi-sport helmets that claim to be for skateboarding that do not have this sticker.
Good brands would be the Bell Faction, Nutcase Crossover, select ProTec helmets.