SQL Server versions of ESdat allow the setting up of multiple "Profiles" for the Chemistry Lookup, such as units and ChemGroups. These settings are specified in the table "zRef_Chemistry_Lookup_Profiles".
Users can manage the profile that is used for their login under Setup - Chemistry - Profiles.
Up to two users can be set as Profile Owners. Only Profile Owners can change the units or chem groups for a profile. DBO users need to nominate themselves as a Profile Owner prior to making changes to a profile.