SITE HISTORY - Laserfiche WebLink

Home Browse Search

Underground Storage Tank Report Page 2 After receiving an acceptance of an Underground Storage Tank Removal Excavation Permit from the offices of the San Joaquin County, Public Health Services, Environmental Health Division, dated November 2, 1998, a permit was issued for the removal of one 10,000 gallon, diesel fuel, underground storage tank(copies of permits are included in Appendix B). Tank product and residual was previously removed and disposed by American Valley Waste by the owner previous to the excavation of the tank by Bowen Construction- Engineering. On November 12, 1998, Bowen Construction-Engineering mobilized to work site and commenced on the removal of one single walled, steel, 10,000 gallon, diesel fuel, underground storage tank. It is the understanding of Bowen Construction-Engineering that the tank had historically contained diesel fuels and was used for the fueling of on-site diesel equipment. A single 1 hp diesel pump, which was used to pump fuel from the UST to equipment on site, was removed and returned to the owner for future use prior to excavation of the UST. The tank was buried under 3' of soil overburden and was located approximately 102' east of maintenance building. Location of tank and fuel pump is given in site plan (Appendix A). During the removal of the overburden,there were signs of discoloration's and petroleum odors were noted. Possible signs of an unauthorized release may be attributed from a leaking product line that was an estimated 15' in length, running from the top of the tank to.a diesel fuel pump cabinet. Excavated soils, an estimated 78 cubic yards, were placed on black 10 mill. visqueen and covered. At completion of tank removal,the tank pit was an estimated 14' in depth, 32' in length and 12' in overall width. Tank backfill consisted of medium grained sand, while the native soils appeared to be sandy clays to medium clays. On Novemberl3, 1998, carbon dioxide, sublimated from 300 lbs. of dry ice, was introduced into the tank to displace potentially explosive vapors. Under the supervision of the City of Stockton Fire, Fire Prevention Department, Inspector Kent Miller and County of San Joaquin Environmental Health Division, an LEL and oxygen reading was taken by a Bowen Construction-Engineering technician,using a Gas Tech 1214 SMPM combustible gas/oxygen detector to determine that the UST was safe to remove. - MXR,T=I RIM . . a