I have found some vocab lists regarding chemistry, physics, internet/computer/programming, metals etc… But is there a list for mechanical/process/environmental engineering? Do you have some list recommendations? Or do I simply look for the wrong keywords when searching lists?
If there are no such lists, would anyone be up to assemble such a list with me?
It sounds like quite a specific list. I would say make a custom list and start building up the vocabulary. If you think it has a wider appeal, we could look at publishing it.
I teach several courses in Chinese for engineers and we use various articles and textbooks, some of them from junior or senior high school in China (we use excerpts from a maths textbook, for example). Although you are of course free to approach this however you want, I would recommend that you read about the topics you are interested in and build your own lists, just like Gwil recommends. If you then realise there is a specific set of words you lack, such as the names of elements or whatever, then you can focus on those for a while, but it’s both more interesting and more effective to get your vocabulary from texts you’re actually interested in reading.
If you want textbooks, check this resource I recommended a while back.
Khan Academy has some voice overs in Mandarin, which are also nice.