This is when I turn to the latest edition of "A to Zoo: Subject Access to Children's Picture Books". This reference title is one I've been using for many years and still is the best source for finding that special picture book. It's divided up into various sections: Subject Headings, Subject Guide, Bibiliographic Guide, Title Index and Illustrator Index. I sailed directly to the Subject Guide and easily found that "Firefighters" has a 'see reference to "Careers- firefighters". So I headed over there to find a long list of 60 picture books that contain something to do with firefighters.
The 8th Edition of "A to Zoo..." contains 13,755 titles that are catalogued under 1,215 subjects.
When I search on-line, I find a list of 34 titles on Goodreads.com but this list includes fire safety non-fiction titles that I don't want.
At Barnes and Noble, they have a very long list of 118 titles but include items published by Lego and Little Golden Books. The last time I saw a Golden Book title, it was in a yard sale, so I'm not convinced about the quality of the items listed and also this publisher won't usually be found in a public library collection.
There are lots of entries when I Google, " Picture Books about Firefighters", but still the listings and information in "A to Zoo..." appear to be of the best quality and you know the source - a reference title in publication for the last 30 years. A real Book! Wow!