To help ensure a smooth transition to ultra low sulfur diesel (ULSD), the Environmental Protection Agency (EPA) is temporarily adjusting the sulfur testing tolerance with a slightly wider range of variability in sulfur level test results. The tolerance will rise from 2 parts per million (ppm) to 3 ppm through October 14, 2008.
EPA said April 20 that the minor change is necessary until more sensitive, more precise tests are in use throughout the fuel distribution system to reliably measure sulfur at very low levels.
The change will help ensure that fuel actually meeting the 15 ppm sulfur cap is not falsely rejected and will not impact the sulfur cap taking effect June 1, 2006.
The adjustment provides labs with more time to improve their measurement techniques, while strengthening the reproducibility of fuel sulfur tests based on current testing variability for some test methods.
The final rule also amends the designate-and-track provisions to account for non-petroleum diesel fuels, such as biodiesel, and makes other minor clarifications.
For more EPA information on the subject, click here