LOS ANGELES (AP) — Impostor service dogs are causing problems for the disabled community and businesses, so the hunt is on for a way to distinguish the real from the phony.

People who refuse to leave their dogs at home are putting vests or backpacks on them that say "service animal" and using them as all-access passes to places permitting only service animals for the disabled. Some pets are interfering with real service dogs, leading to worries about their safety.

Other impostors create health problems in restaurants or damage merchandise at retail stores. Passing pets off as service animals is a federal crime, but prosecuting pretenders is nearly impossible under laws meant to safeguard the privacy of those questioned about their animals. Efforts are underway to make cases easier, but there's no unified plan.