36 CFR 218.9: Evidence of timely filing.

(a) It is the objector's responsibility to ensure timely filing of a written objection with the reviewing officer. Timeliness must be determined by the following indicators:

(1) The date of the U.S. Postal Service postmark for an objection received before the close of the fifth business day after the objection filing period;

(2) The agency's electronically generated posted date and time for email and facsimiles;

(3) The shipping date for delivery by private carrier for an objection received before the close of the fifth business day after the objection filing period; or

(4) The official agency date stamp showing receipt of hand delivery.

(b) For emailed objections, the sender should receive an automated electronic acknowledgement from the agency as confirmation of receipt. If the sender does not receive an automated acknowledgment of receipt of the objection, it is the sender's responsibility to ensure timely filing by other means.