Ohio Revised Code Title XLI. Labor and Industry § 4123.85

In all cases of occupational disease, or death resulting from occupational disease, claims for compensation or benefits are forever barred unless, within one year after the disability due to the disease began, or within such longer period as does not exceed six months after diagnosis of the occupational disease by a licensed physician or within one year after death occurs, application is made to the industrial commission or the bureau of workers' compensation or to the employer if the employer is a self-insuring employer.