Ontario Regulation 225/07 filed on June 6, 2007 amended Ontario Regulation 675/98 (Classification and Exemption of Spills). The Regulation amends the definition of a Class X Spill and specifies when notice is required to be given to the Ministry of the Environment, notwithstanding the general exemption from the obligation to give notice. A Class X spill has been redefined as a spill that does not enter and is not likely to enter any waters and immediately before it occurs is described as "non-reportable" in a spill contingency plan that meets the "Emergency Preparedness and Response" (CAN/CSA-Z731-03) standards. Subsection 10(3) of Regulation 675/98 as amended now provides that notice is to be given where the quantity spilled is more than the amount specified in the Spill Contingency Plan established pursuant to Ontario Regulation 224/07, where the spill was caused deliberately, if the spill causes adverse effects, if arrangements for remediation were not made and where the spill enters water or is likely to enter waters.

The Regulation adds Part II, which sets out, in detail, the notification requirements for persons who are required to give notice of a discharge or a spill. The information required to be provided includes not only information about the substance which is the subject of the spill, but also includes any relevant information regarding the cause of the discharge, the circumstances surrounding the discharge, or where the cause is not known, the person's assessment of the most likely cause based on the best information available, and an explanation of steps that have been taken or will be taken to determine the cause. A description of adverse effects that occurred or may occur, and a description of the conditions that may aggravate or mitigate the adverse effects is also required.