Modifier out of Place?

Not infrequently, when you write, you need to modify something twice, and this can lead to confusion. What does that second modifier refer to—does it refer to that original thing or to something in the first modifier?

For example:

These frequently criticized single-use bags, which have made something of a comeback in the COVID-19 era, are the byproduct of natural gas extraction, effectively reusing ethane gas that would be otherwise wasted by turning it into plastic.

What does “by turning it into plastic” refer to? The bag, or ethane? Does it mean “wasted by turning it into plastic,” or does it mean “reusing ethane gas by turning it into plastic”?

The context of this essay makes it pretty easy to figure out what the sentence means, but the sentence jumped out at me because “by turning it into plastic” has to jump over the closest candidate, “wasted” to get to its referrent.

You can’t always do it, but when you use a modifier, try to make the modifier refer to the closest candidate.