DEQ evaluates data submitted by external parties to determine that the data are of sufficient quantity, type, and quality before they are used to make decisions. DEQ’s evaluations are conducted using the following quality assurance project plans and standard operating procedures (deviations due to site-specific circumstances may occur).

UST Closures, Petroleum Site Assessments, and Corrective Action

• How DEQ Evaluates Site Assessment and Corrective Action Data
• Data Review, Verification, and Validation of External Party Petroleum Data Quality Assurance Project Plan and Standard Operating Procedure (July 2025)

Used Oil UST Closures and Release Sampling

• How DEQ Evaluates Sample Collection and Data Analysis for Used Oil UST Closures and Releases
• Used Oil UST Closure and Release Sampling Standard Operating Procedures (May 2017)

Petroleum-Contaminated Soil

• Standard Operating Procedures for Management and Disposal of Petroleum-Contaminated Soil Following a Release from a Non-Underground Storage Tank Petroleum Storage Tanks (February 2014)
• Standard Operating Procedure for Landfarming Petroleum-Contaminated Soils (July 2017)