40 CFR 265.76 - Unmanifested waste report.
(a) If a facility accepts for treatment, storage, or disposal any hazardous waste from an off-site source without an accompanying manifest, or without an accompanying shipping paper as described by § 263.20(e) of this chapter, and if the waste is not excluded from the manifest requirement by this chapter, then the owner or operator must prepare and submit a letter to the Regional Administrator within fifteen days after receiving the waste. The unmanifested waste report must contain the following information:
(2) The date the facility received the waste;
(7) A brief explanation of why the waste was unmanifested, if known.