Federal officials are further clarifying the rights and responsibilities of people with disabilities who rely on service animals amid continued confusion.

Four years ago, the U.S. Department of Justice issued revised rules on service animals under the Americans with Disabilities Act. But the agency has received so many questions since that time that it’s trying again with a new 8-page technical assistance document.

The latest effort includes 37 questions and answers covering everything from what type of work a service animal might perform to how they are trained and what sort of animals qualify.

“The ADA requires state and local government agencies, businesses and non-profit organizations (covered entities) that provide goods or services to the public to make ‘reasonable modifications’ in their policies, practices or procedures when necessary to accommodate people with disabilities,” the Justice Department states. “Accordingly, entities that have a ‘no pets’ policy generally must modify the policy to allow service animals into their facilities.”

The document defines a service animal as a dog that has been “individually trained to do work or perform tasks for an individual with a disability” that is directly related to their disability. No certification, licensing, identification or documentation is required.

Service animals can accompany people with disabilities in a wide variety of circumstances including at salad bars or other self-service food lines, in ambulances and hospitals and at hotels where they should not be limited to or charged extra for “pet-friendly” rooms, the Justice Department said.

Under federal law, businesses looking to assess if a dog is a service animal may only ask if the animal is required due to a disability and what work or task the dog is trained to perform.