(a) No benefits shall be payable to or on behalf of a claimant who has filed a claim under section 415 of part B of title IV of the Act, for any period of eligibility occurring between July 1, and December 31, 1973, unless the claimant has filed and diligently pursued a claim for benefits under an applicable State workers' compensation law. A State workers' compensation claim need not be filed where filing would be futile. It shall be determined that the filing of a State claim would be futile when:
(1) The period within which the claim may be filed under such law has expired; or
(2) Pneumoconiosis as defined in part 718 of this subchapter is not compensable under such law; or
(3) The maximum amount of compensation or the maximum number of compensation payments allowable under such law has already been paid; or
(4) The claimant does not meet one or more conditions of eligibility for workers' compensation payments under applicable State law; or
(5) The claimant otherwise establishes to the satisfaction of the Office that the filing of a claim under State law would be futile.
(b) Where the Office determines that a claimant is required to file a State claim under this section, the Office shall so notify the claimant. Such notice shall instruct the claimant to file a State claim within 30 days of such notice. If no such State claim is filed within the 30-day period, no benefits shall be payable under this part to the claimant for any period between July 1, and December 31, 1973.
(c) The failure of a claimant to comply with paragraph (a) of this section shall not absolve any operator of its liability for the payment of benefits to a claimant for periods of eligibility occurring on or after January 1, 1974.
(d) The deputy commissioner may determine that a claimant is ineligible for benefits under section 415 of part B of title IV of the Act without requiring the claimant to file a claim under a State workers' compensation law.