Hillis-Carnes was retained by a major multinational oil and gas corporation to assess and remediate petroleum leakage through cracks and cold joints in a 70-year-old, cast-in-place box culvert Terminal in Baltimore. The box culvert, which conveys storm water from east Baltimore to the Chesapeake Bay, is located 18’ below existing ground surface. The Hillis-Carnes Environmental Department and our chemical testing subconsultant determined the constituents in the leakage entering the inside of the culvert. Hillis-Carnes designed a remediation plan to arrest the leakage inside of the box culvert. The remediation plan consisted of the injection of a chemical grout through vertical grout pipes along the outside of the box culvert. Holes drilled horizontally into the concrete sides of the box culvert were monitored for the appearance of the chemical grout. When chemical grout was detected flowing into the box culvert through the horizontally drilled hole the grout injection was terminated. The chemical grout was designed to solidify along the exterior of the box culvert thus sealing the interior of the culvert from future leakage. Hillis-Carnes has performed periodic six-month inspections of the box culvert since 2001.