What is meant by "de minimis concentration"?

The term "de minimis concentration" refers to levels of a substance that are so small that they are considered negligible or insignificant. In the context of underground storage tank regulations, this often means a concentration that does not exceed one inch of a regulated substance or is below a specified reportable quantity. These thresholds suggest that while the regulated substance may be present, its impact or risk is minimal and thus does not warrant regulatory action.

Understanding this concept is crucial for site assessments, as it helps in determining when it is necessary to report findings to authorities. Recognizing what constitutes a de minimis concentration allows for more efficient management of environmental concerns, focusing resources on significant issues rather than those that are trivial.