I am applying to grad school for a Masters in Environmental Science. (My BS is in Biology). I interned throughout high school and college for NIH. I did the basic lab tech type of work, but there were 2 papers that were published which I helped work on. Obviously, I am not an author on either of those papers, however I think they show the kind of work of which I have been a part. I can't find any format for listing this type of thing, so perhaps I should exclude the reference completely? However, I went to a CV writing workshop and was advised that any papers I contributed to in any way should be listed. I would appreciate any advice on this subject. Thank you.
However, I went to a CV writing workshop and was advised that any papers I contributed to in any way should be listed.
That's bad advice for an academic CV. You only list papers on which you are an author. I haven't ever seen exceptions to this rule - if you list them it will at best be confusing, and at worst seen as fraudulent.
You can certainly list your job as research experience, and in any graduate application, you can and should explain in more detail what you did and how it contributed to published research. You should also ask your supervisor or PI to write a letter of recommendation which explains your contributions and their importance, and how it shows your preparation for graduate study.