Compressor Station Background
Work at this natural gas compressor station was performed in Greene County, Virginia under an Administrative Order on Consent between the client and the U.S. EPA. PCB-impacted paint was discovered at multiple locations throughout the facility. After AGES conducted delineation sampling to further evaluate the extent of PCB-affected components, it was determined that remedial action was required on paint found in three separate buildings at the site. Remediation was needed in several low and high occupancy areas including walls, ceilings, doors, rafters, cabinets and pipes. Response actions began in 2013, with AGES performing oversight of the field work and collecting confirmatory samples, as needed.
Failing Paint Removal: PCBs Below WELs
Grossly peeling paint in some areas contained PCB; but, in concentrations less than the previously determined Worker Exposure Levels (WELs). For these areas, all damaged paint was removed by manual scraping, chemical stripping, shot-blasting or brush-grinding. Paint removal was followed by a double wash and rinse. Then, the designated areas were covered with a single coat of paint, per the client’s specifications.
Failing Paint Removal: PCBs Above WELs
For PCB-impacted paint with contaminant concentration levels exceeding WELs, all damaged paint was removed from surfaces, as needed, using abrasive methods such as manual scraping, shot-blasting, chemical stripping, brush-grinding, or similar methods. The method of paint removal and surface preparation varied according to the client’s specifications and conditions of the component. After damaged paint removal and a double wash/rinse, the designated surfaces were double-coated with two (2) layers of contrasting-colored paint, in general accordance with the continued use authorization under 40 CFR 761.30 (p) (A) (1).
Complete Removal from Metal Surfaces to NACE 2 Standard
Some metal components required complete removal of all PCB-impacted paint, both damaged and intact. In general accordance with 40 CFR 761.79, complete paint removal from metal surfaces was completed to meet the National Association of Corrosion Engineers (NACE) 2 standard for blasting to a near-white finish.
Once the NACE 2 standard was achieved, the area was painted with a single coat of epoxy, per the client’s corporate standards. If paint removal did not meet the NACE 2 standard, then wipe samples were collected to confirm that PCB-impacted paint had been removed. Once results for the designated area reached the action levels, the area was painted with a single coat of epoxy, per the client’s corporate standards.
A plastic containment was constructed around each work area to contain all blasting material. All paint was removed using either a dry-ice freeze blasting unit, sandblasting unit, a needle gun, and/or rotopene connected to a dustless, portable vacuum.
Complete Removal from Concrete
For some concrete components, complete removal of all PCB-impacted paint, both damaged and intact, was performed instead of a double-wash/rinse and single-coating or double-coating. If complete paint removal from concrete that had not been previously characterized was performed, concrete chip samples were collected to confirm that all PCB-impacted paint was removed and to confirm that the underlying concrete was not impacted by PCBs. The area was then re-painted per the client’s corporate standards.