Respondent was assessed a civil penalty of $4,545 for three violations of the HMR, when he represented, marked, and certified DOT specification and special permit cylinders as qualified for continued service in accordance with the HMR when his RIN had expired so that he was not authorized to requalify DOT specification and special permit compressed gas cylinders for continued service (violation No. 1); he failed to assure the accuracy of his hydrostatic retest equipment on days when he retested and requalified DOT specification and special permit compressed gas cylinders for continued service (violation No. 2); and he failed to maintain complete and accurate records of cylinder requalification and retest system calibration (violation No. 3).