Paint Waste Area Unexploded Ordnance Site 13 Record of Decision/Final Remedial Action Plan

The California Department of Toxic Substances Control (DTSC) approved the Record of Decision (ROD)/Final Remedial Action Plan (Final RAP) for the Paint Waste Area (PWA), also identified as Unexploded Ordnance (UXO) Site 13, located at the Former Mare Island Naval Shipyard (MINS) in Vallejo, California. Within the PWA, the remaining paint waste debris and associated soil contamination, and the potential for incidental munitions and explosives of concern (MEC) hazards beneath the detection depth limits of available technology will be addressed by the remedial action described in the ROD/Final RAP. The actions consist of the following: •Soil excavation and offsite disposal for the PWA Target Treatment Zone (TTZ) A and Institutional Controls (ICs) for incidental MEC for both TTZ A and TTZ B to restrict certain sensitive uses of the property and prohibit ground-penetration. The remaining paint waste debris and lead contamination within TTZ A will be excavated, mechanically screened to remove MEC, and transported to a permitted offsite waste disposal facility. •Soil will be excavated to an estimated depth up to 4.5 feet below ground surface (bgs). The impacted soil is estimated at 818 bank cubic yards (cy) from TTZ A with an additional estimated 182 cy of overburden or extra soil from benching the excavations. After excavation is completed and no visual deposits of paint waste remain, lead confirmation samples will be collected at the extent of the excavations. •The excavations will be backfilled with clean imported soil (approximately 1,000 bank cy), compacted, and restored to match pre-excavation conditions. •Excavated areas will be hydroseeded with native grasses to prevent erosion and revegetated with wetland plant species, such as pickleweed cuttings and salt grass, to promote appropriate nontidal wetland habitat and monitored to confirm that agreed upon wetland revegetation criteria are met.