Upon receipt of the miner's employment history, the district director shall investigate whether any operator may be held liable for the payment of benefits as a responsible operator in accordance with the criteria contained in Subpart G of this part.

The district director may identify one or more operators potentially liable for the payment of benefits in accordance with the criteria set forth in § 725.495 of this part. The district director shall notify each such operator of the existence of the claim. Where the records maintained by the Office pursuant to part 726 of this subchapter indicate that the operator had obtained a policy of insurance, and the claim falls within such policy, the notice provided pursuant to this section shall also be sent to the operator's carrier. Any operator or carrier notified of the claim shall thereafter be considered a party to the claim in accordance with § 725.360 of this part unless it is dismissed by an adjudication officer and is not thereafter notified again of its potential liability.

The notification issued pursuant to this section shall include a copy of the claimant's application and a copy of all evidence obtained by the district director relating to the miner's employment. The district director may request the operator to answer specific questions, including, but not limited to, questions related to the nature of its operations, its relationship with the miner, its financial status, including any insurance obtained to secure its obligations under the Act, and its relationship with other potentially liable operators. A copy of any notification issued pursuant to this section shall be sent to the claimant by regular mail.

If at any time before a case is referred to the Office of Administrative Law Judges, the district director determines that an operator which may be liable for the payment of benefits has not been notified under this section or has been incorrectly dismissed pursuant to § 725.410(a)(3), the district director shall give such operator notice of its potential liability in accordance with this section. The adjudication officer shall then take such further action on the claim as may be appropriate. There shall be no time limit applicable to a later identification of an operator under this paragraph if the operator fraudulently concealed its identity as an employer of the miner. The district director may not notify additional operators of their potential liability after a case has been referred to the Office of Administrative Law Judges, unless the case was referred for a hearing to determine whether the claim was properly denied as abandoned pursuant to § 725.409.