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5.0 CONCLUSIONS AND RECOMMENDATIONS <br />The following is a summary of the findings for the Hazardous Waste Tank System and the <br />associated piping and ancillary equipment: <br />The hazardous waste tanks are compliant with the regulations identified in 22 CCR 66265. <br />However, based on manufacturer specifications, permeation of the tank contents into <br />polyethylene may occur depending on each chemical. Ethylene glycol (antifreeze) does not <br />attack or permeate high density crosslinkable polyethylene (XLPE) resins up to 100° F. <br />Petroleum hydrocarbons (such as fuel oil, diesel, etc) does not attack high density <br />crosslinkable polyethylene resins; however, they will be absorbed into the wall of the tank <br />and permeation and loss will occur. It is not recommended for polyethylene tanks containing <br />used oil to be stored at room temperatures above 100° F. In addition, the manufacture <br />states that the general life expectancy of the crosslink polyethylene tanks is 10+ years with <br />15 to 20 years being common depending on chemical, concentration, temperature, <br />installation and piping, and venting. The serial numbers on the used oil tanks and the waste <br />antifreeze tanks indicate manufacture dates of 1995 or earlier (with the exception of 02 with <br />an approximate manufacture date of 2009). In addition, the tanks appeared to be in good <br />condition; however, several of the tanks appeared to have discoloration due to possible <br />permeation of the tank contents overtime. Based on the fact that the tanks are at the upper <br />end of their life expectancy it is recommended that replacement of tanks be evaluated on a <br />case-by-case basis. The tanks should be inspected daily for leaks and/or damage by site <br />personnel using the inspection form provided in Appendix E or an equivalent Pick -N -Pull <br />document. <br />Secondary containment associated with the hazardous waste tank system is compliant with <br />the regulations identified in 22 CCR 66265. It is in good condition with no apparent leaks or <br />other damage. The containment volume is sufficient to contain the volume of the largest <br />tank and longest piping run within each compartment. The XLPE materials of construction <br />are compatible with the materials stored subject to the exceptions specified above for the <br />tanks. The secondary containment should continue to be periodically inspected by site <br />personnel for evidence of leaks and/or damage. <br />The piping associated with the hazardous waste tank system is compliant with the <br />regulations identified in 22 CCR 66265. It is in good condition with no leaks or other <br />damage and is compatible with the service for the used oil and waste antifreeze tank <br />systems. All piping is adequately supported and protected against physical damage or <br />stress. The piping should continue to be periodically inspected by site personnel for leaks <br />and/or damage and repaired as necessary. <br />The ancillary equipment associated with the hazardous waste tank system is compliant with <br />the regulations identified in 22 CCR 66265. The gravity piping from open funnels to each <br />waste tank acts as atmospheric vents preventing the development of vacuum or pressure. <br />However, emergency vents are not present on any of the waste tanks. EarthCon contacted <br />the engineering department at Poly Processing, the tank manufacturer, to discuss <br />emergency venting of the tanks at the Site. The tanks are rated for usage under <br />atmospheric conditions and the manufacturer does not recommend the use of commercially <br />available emergency vents because the activation pressure exceeds the recommended <br />working pressure of the tank. The manufacturer recommends utilizing the current <br />Hazardous Waste Tank Assessment Stockton, CA <br />Auto Parts Group — Pick -N -Pull 7 Project No. 211283 <br />