Find out who provides the public safety divers in the area(s) you want to work. Normally it will be a law enforcement agency or a fire department, sometimes a volunteer organization.
In nearly all agencies public safety diving is not a full time job- it's an extra duty on top of being a law enforcement officer or firefighter.
See if they use only their full time personnel or if they also use reserves or volunteers. If they only use their full time folks then you will need to get hired, go through their academy or training program. If they use volunteers ask what the requirements are to join.
For the agencies that use full time personnel find out how long you have to be on the agency before you can apply to be on the team (In many agencies it will be several years). If they use reserves or volunteers then find out what training they expect you to have before you can join and what training they will put you through after you are hired.
Do some research before anything else- asking the question here shows you are on the right track.
Do a bit of reading- some books I like- Encyclopedia of Underwater Investigations by Robert Teather, Public Safety Diving by Walt Hendrick and Andrea Zaferes and PSDiver by Mark Phillips.
Most public safety diving courses are sponsored by these agencies and many are only open to folks that are already on teams. (teaching only folks that are covered by workers compensation should an injury occur tends to lower the liability risks)
Your profile indicates you only have a couple dozen dives so far, get with a shop or club or find a buddy and go out and get some experience under your belt, as you get more dives in your skills will improve and you will be a better candidate for a team.
Public safety diving is a highly specialized area and while many of the recreational courses you mention may not be directly applicable they all add to your experience level and help you start to develop skills that will help you throughout your diving career, sport diving or PSD.
One final thought- if you run across local dive shops or sport diving instructors offering training in public safety diving make sure that the course is being taught by someone with actual experience in public safety diving (and tagging along for a couple of callouts is not enough). If they don't have actual experience in the field save your money and go elsewhere.
Good luck!
