What measurement indicates that a release has occurred?

The measurement that indicates a release has occurred is TPH (Total Petroleum Hydrocarbons) above 50 ppm in soil samples. This threshold is significant because it aligns with the regulatory framework for environmental safety and monitoring in Oregon. TPH levels in soil exceeding this amount suggest that there has been a significant release of petroleum products, which could pose risks to human health and the environment. Recognizing this level as a threshold helps ensure that appropriate actions are taken to investigate and remediate contamination if necessary. This understanding is critical for supervisors managing heating oil tanks to maintain compliance with environmental regulations and to protect public health.

Determining the level of TPH in both soil and water is essential for assessing contamination; however, the specific threshold of 50 ppm in soil samples has been established as particularly indicative of a release, triggering further investigation and remedial efforts to address any risks presented by the contaminant.