Just to be clear, I think the Senate initially said that they should be mandatory, and then at the end, by unanimous consent, changed it to discretionary again. I don't want to misspeak, but that's my recollection of what happened.
Just from the perspective of how these instruments are used, there is a range of instruments that are available under CEPA to manage the risks of toxic substances, and pollution prevention planning is one of them. You wouldn't want to require it in every case, because often you're prohibiting the substance. Why would you require a pollution prevention plan if what you're going to do is regulate to prohibit it outright? The amendments that are proposed do explicitly say these can be used to promote alternatives and also include a discretionary requirement to allow the minister to ask for interim progress reports. They will make it easier to track progress and whether the tools are working or not.