Project Profile: United Pacific Gas Station & Mechanic Shop Demolition

San Mateo, California

An in-depth “tree protection plan” and a last-minute change of plans for a site post-work presented the CGRS California Refined Fuels team with new challenges and extended delays to removing a longstanding gas station and mechanic shop in San Mateo, California.

APRO, LLC, a division of United Pacific, contracted with CGRS to remove the fuel system above and below ground and an 800-square-foot building, then restore the site to an undeveloped lot. A gas station and mechanic shop – most recently Tad’s 76 and AT Auto Care – had occupied the location for 40-plus years. The business closed October 1, 2021.

The job entailed:

  • Emptying, inerting (purging vapors), removing and disposing of two approximately 12,000-gallon underground storage tanks (USTs) that held unleaded gas and diesel and a 500-gallon waste-oil UST, all of which were double-wall steel tanks
  • Removing and disposing of five dispensers, 450 feet of piping and all associated equipment
  • Demolishing the convenience store and mechanic shop
  • Sampling soil and groundwater in the tank basin to test for presence of petroleum hydrocarbons, none of which was detected; the tanks showed no signs of rust, pitting or other indications that fuel may have leaked
  • Installing a 3-foot-tall decorative fence and creating a 5-foot-wide buffer with landscape on three sides of the property, per City requirements

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Another unique aspect of the project was the City requirement that a licensed arborist prepare a “tree protection plan” for the site before demolition began. To adhere to the plan, the CGRS team:

  • Installed temporary chain-link fences around seven trees on and around the lot to establish a “no-disturbance zone” of the soil around them and identify them as off limits to equipment and materials storage or cleaning
  • Pruned two trees’ branches to prevent entanglement with heavy equipment
  • Wrapped four trees’ stems with trunk buffers and 10 trees with root buffers
  • Hand trenched for foundation or utilities under the trees’ branches or “drip zones”

Upon inspecting the site throughout the project and its completion, the arborist found the trees were in as good of shape as they were prior to the work.

While demolition of the approximately 12,000-square-foot site began in mid-February, the work of obtaining permits from the City of San Mateo, the California Certified United Program Agency (CUPA), the San Mateo Consolidated Fire Department and the Bay Area Air Quality Management District (BAAQMD) to proceed began eight months earlier. The extensive tree protection plan, with requested revisions, resubmittals, site visits and final approval, made up about four months of that time.

Near the end of the job, after CGRS had removed the fuel system and building, the customer requested the remainder of the lot’s ground cover stay and the team place asphalt over the excavated store pad, tank pad, and pipe trench. The job required 7,000 square feet of asphalt, but the change in plans have resulted in a several weeks’ delay of the site’s final inspection.

The site work went according to plan, with CGRS completing it according to the customer’s and regulatory agencies’ specifications March 11, and the lot is currently serving as a temporary parking area for workers at a nearby construction project. The site received its final inspection and approval April 25, 2022.