There is a school of thought that says that newer employees are leaving now because they do not have a pension plan that ties them to this company. However pension plan for new employees has been done away with in 2010, more than 11 years ago, and hence it begs the questions " Why this alarming attrition now". Here are some thoughts :-
1) zero to little career growth / development scope for technical employees. Unless someone is in management, promotions are very difficult ( esp. after a certain level). Also unless someone is a "diversity" technical candidate, one is stuck in their current position, pretty much forever.
2) Promotions for technical folks were always difficult ( going back at least 20 years), but now the bar has been raised so high, that it is almost impossible after a certain level. We had 3 layoffs in the last 3 years, with no end in sight, and whatever job security / stability was there is now gone. Thus limited career options coupled with job insecurity makes leaving this place easier if someone is a newer employee.
3) Looks like some people are leaving with part time / lower paying jobs. Perhaps it means that the current job is not technically challenging enough for such employees.
4) Rise of tech companies in the west coast who are now hiring lot of chemists, chemical engineers since they are heavily investing in hardware. They pay way better than MInnesota MIning.