The Occupational Safety and Health Administration (“OSHA”) conducted an inspection of Respondent’s worksite located at 4827 Dodge Street. Omaha, NE on March 11, 2019. Tr. 31-34, 105. On August 2, 2019, OSHA issued one citation with one serious item (“Citation”) to Respondent. Tr. 60, 104; Exh. C-9. The Citation proposed Respondent pay a penalty in the amount of $9,282.00. Exh. C-9. OSHA mailed the Citation to Respondent via United States Postal Service (“USPS”) certified mail on August 2, 2019. Tr. 60. Angela Rieber signed for the certified mail based on the certified mail return receipt provided by USPS, but the date she signed for it did not appear on the receipt. Tr. 108-09; Exh. C-10. Complainant used the date it received the receipt from the USPS as the date to begin the 15-day calculation. Tr. 109-110; Exh. C-8. Therefore, the Citation was received by and signed for by Respondent.