Thank you. I'm happy to respond.
I think the government shares the concern about defining “cumulative effect” in two senses.
One, we don't think it's necessary or appropriate to define it in the act itself, because it is a concept that continues to evolve within the scientific community, and defining it in the act would then lock it in and preclude us from being able to evolve on a policy basis.
Second, we also have concerns about the definition that is proposed, which is at variance with the approach we've included in other parts of the bill, including in proposed section 68, which provides ministers with the power to collect information on various topics, including on whether exposure to a substance in combination with exposure to other substances has the potential to cause cumulative effects.
This kind of information-gathering would not be restricted to substances that have common mechanisms or modes of action. It would go well beyond that and allow us to look at the cumulative effects from multiple completely different substances that may have different kinds of mechanisms or modes of action, or even different effects.
Therefore, this would be unnecessarily restrictive. It's also an example of why, in many cases, when a concept is being introduced that is evolving in science, it's best left to the government to clearly and publicly define it as a matter of policy and put that definition out but then let it evolve as the science evolves.
Just on the issue of “aggregate exposure”, the term doesn't appear anywhere else in the bill, so it's not clear what the legal implication of defining it would be.