Shared Services is based on four interrelated tiers: online self-service tools, the HRSC in Charleston, the nine HR Service Providers (based in bureaus throughout the Department) and the HR Bureau in Washington (corporate HR).
Diacetyl has been found in numerous different e-cigarette liquids. Popcorn lung is an irreversible condition and although the electronic cigarette industry is largely aware of this challenge, it cannot be verified whether or not every different manufacturer of e-cigarette liquid has taken the appropriate precautions to remove it from their products.
At the bottom of this page there is a FAQ about Diacetyl by Liberty flights but more importantly there is a list of the flavourings they sell which contain Diacetyl and the amount they contain. A cached mirror of that page is here and I will reproduce the list below. This list does not appear to found on their US site. Apple pie 0.4; Beer 0.001; Butter 1.5