Letterle is a veteran-owned, small business, environmental consulting and remediation firm with offices in Allison Park, Pennsylvania (Allegheny County), Franklin, Pennsylvania (Venango County), and Bellefonte, Pennsylvania (Centre County). Letterle is a Pennsylvania limited liability company that is also registered to do business in West Virginia, and holds a contractors license issued by the West Virginia Contractor Licensing Board. Letterle specializes in the investigation and remediation of petroleum releases, particularly former underground storage tank release locations. Key Letterle personnel have extensive experience with Phase I/II ESAs and redevelopment projects throughout the United States. A growing area of Letterle's business is assisting clients with their regulatory compliance in areas such as NPDES permitting, spill plans, waste reports, and response to compliance actions. Currently, Letterle's caseload includes over 100 former underground storage tank release sites located in Pennsylvania, West Virginia and Maryland. At least 80% of those projects are currently funded by the Pennsylvania Underground Storage Tank Indemnification Fund or private insurance. Letterle currently operates over 30 soil and groundwater remediation systems at sites in Pennsylvania and West Virginia. The majority of the remediation systems are either vacuum enhanced groundwater extraction systems or total phase extraction systems.