Try google search the LC processing time, some law firms may have the data, in my memory. Especially for the fast lane PERM, the LC processing time depends on the category under which you are apply for. Some categories like computer programmer, system administrator, accountant, got LC really fast; while other categories might take long. It also depends on the years, in 2005 or so, it was really fast: my colleagues (faculty in an university) got it in one week, in two weeks, and in six months. (I have three colleagues went through LC PERM in 2005-2006. While before 2005 PERM, the usual LC took 1.5 to 2 years. Nowadays, it could be 0.5 to 1 year.
I don't have any solid evidence for the above sayings though: heard the stories here and there.
In my memory in exact this forum, someone already tried this approach: for the 3rd prong in NIW, said something about LC, and it didn't go through. Search in this forum. There are discussions and suggestions on how to prepare for the 3rd prong in NIW positively.
Reading the 3rd prong you quoted, to me it seems that you need to emphasize your serve and your work is the interest of the country. The damage due to toxic minerals in US is fine as long as it links to your field, but again you might want to emphasize more on how your work can IMPROVE the living in US. I wouldn't say too much about the LC procedure negatively. Similar to the case: you want to show that you are very intelligent , saying all the people in US are stupid offends the officers, the better way, you say that you are better than the others in your fields.
