The best-kept secret in California comp is a state fund that pays people whose combination of old and new disability crosses 70% — including old conditions that never saw a claim form. Attorneys mine files for it; unrepresented workers almost never find it. Here it is.
Why the fund exists
Without it, hiring a worker with one bad eye or an old back would mean insuring the whole history — so nobody would. §4751 splits the bill instead: the employer’s carrier pays for the new injury as if it stood alone; the SIBTF pays the delta between that and the combined disability. Pre-existing means any origin — military service, diabetes, a childhood accident, a prior work injury already settled.
The two doors and the 70% floor
Door one: the subsequent injury rates 35% or more standing alone, considered without adjustment. Door two: the new injury hits a paired member — arm, hand, leg, foot, eye — opposite a previously impaired one, and rates at least 5%. Through either door, the old and new must combine to 70%+ overall. Notably, SIBTF combination math is additive rather than the CVC discount — one of the few places in this system where disabilities stack at face value.
Who this actually helps
Veterans with service-connected conditions plus a work injury are the classic file. Diabetics with neuropathy, workers with prior fusions or amputations, one-eyed and one-kidneyed workers — anyone whose new claim rates heavy while their history was already disabling. The thresholds are pure rating arithmetic: the calculator prices the new injury’s standalone percentage, which is the 35% door’s whole question. High-combination cases pay at life-pension-like levels, litigated against the fund at the WCAB alongside the main case.
Estimates for informational use; not legal advice — SIBTF practice is specialized, and counsel is close to mandatory.
Rate your spine right here
Same engine as the tables above — pick your occupation and age, slide the WPI from the report, and carry it into the full calculator when you’re ready.