Oklahoma Employee's First Notice of Occupational Disease and Claim for Compensation is an official form issued by the Oklahoma Workers' Compensation Commission (OCC) to notify employers of an employee's claim for compensation due to an occupational disease. This form is required to be completed by the employee when filing a claim for compensation due to a work-related illness or injury. The form must be filed within one year of the employee's knowledge of the occupational disease or injury. It includes information about the employee's job duties, the date of onset of the disease or injury, any medical treatment received, and any witnesses to the injury. There are two types of Oklahoma Employee's First Notice of Occupational Disease and Claim for Compensation: Form 3-A, which is for claims for occupational diseases, and Form 3-B, which is for claims for occupational injuries. Both forms must be completed and filed with the OCC in order to receive workers' compensation benefits.