California Labor Code Section 5412
In Chavira v. Workers' Comp. Appeals Bd. (1991) 235 Cal.App.3d 463, the Court of Appeal undertook an extensive discussion of when a worker with an insidious, progressive disease sustains an injury for purposes of filing a workers' compensation claim.
Labor Code Section 5412 states:
"The date of injury in cases of occupational diseases or cumulative injuries is that date upon which the employee first suffered disability therefrom and either knew, or in the exercise of reasonable diligence should have known, that such disability was caused by his present or prior employment." An application for benefits must be filed within one year of the date of injury. ( 5405.) The court indicated disability for purposes of section 5412 means either temporary disability, i.e., loss of earnings, or permanent disability, i.e., loss of earning capacity with or without an actual loss of earnings. (Chavira, at pp. 473-474.)