Clean Water Act
The Water Pollution Control Act (WPCA) is Public Law 92-500. The Oil Pollution Act (OPA) is Public Law 101-380. Both prohibit discharge of oil or related substances on the ground. Both relate to the paving industry, and are the reasons why it is no longer permissible to use diesel fuel to clean equipment with, or as a release agent.
Both Acts define “oil” in the same way:
“oil of any kind or in any form, including, but not limited to, petroleum, fuel oil, sludge, oil refuse, and oil mixed with wastes…”
Literature by the major petrochemical producers indicates that petroleum distillate fractions, even with some modification of the chemical structure, are still considered “oils” under these Acts. Therefore, diesel fuel, being a fuel oil, is considered an oil under these Acts.
This would also cover petroleum-based hydrocarbon solvents, such as are sometimes used to dilute d-limonene or other terpenes touted as “natural” solvents. The presence of petroleum-based solvents in these mixtures means that they are classified as oils, and are therefore forbidden to be used in handling asphalt in the field.
View the WPCA and OPA Impact and Implications for the Paving Industry (PDF 47k)
Michael G. Kinnaird, Ph.D.