I am not sure that what you're proposing is practical or feasible. How do you handle people switching jobs into or out of a dangerous career field? How do you handle changes to the career field designation as dangerous or not? Who's going to make those calls? How are you going to authenticate somebody's designation to be accurate? Sounds like an increased chance of fraud to me. I think you would need a lot more SSA employees than you do now to verify the data. Plus it's going to cost a lot to rewrite the SSA programming and quite a bit of time to get it right.
I think people go into dangerous career fields voluntarily; they know what they're doing and no doubt they are highly paid to do it. In some cases, the people in those careers get an early pension, like the military does after 20 years of service.
All the things you bring up are easy to work out, otherwise it's flat out amazing at what technology especially AI is capable of today.
Career fields would be rated, so if one goes in and out of the career fields, then the rate of deduction would be adjusted based upon the change made.
Example - Underwater welder is rated at risk level 12 in the SS system for one example vs. Matress tester that is in the furniture making business, and that would have a risk level rating of say 8.
Ok, so it depends on how long one serves in either career field that would then determine the time of departure for retirement out of the workforce.
Example 1 - Underwater welder if served for the majority of his time as an underwater welder (65% for example), and having a higher rate of deduction due to that high risk career field, then it should allow the person to retire at the age of say 59 to then draw his full retirement benefit at that age.
Example 2 - Matress Tester, if served in that career field for 65% of their time, and at the lower rate deduction, then that person will be forced to retire at a later age (65 for example), in order to draw their full retirement benefit.
So this is how the system should be operating out of fairness to the worker's.
High risk vs low risk is the big issue, and physical and mental degradation should absolutely be considered in the make up of these government run program's.
Socialism is a bad idea, and it screws people over bad in the end.
The system has seemingly been set up in hopes that people die on their job's before ever collecting their government managed pensions/retirement SS incomes that they had worked for.