A Classification Unit is a grouping defined by WorkSafeBC. It groups employers in similar industries with similar injury risk levels together to facilitate fair and equitable assessment rates. For example, the Classification Unit 766011 groups together long term care facilities, homes for the physically challenged, and multilevel care facilities together (among others). A full description of the 766011 unit can be found through WorkSafeBC here.
As an employer, your WorkSafeBC-provided documentation will identify what Classification Unit you belong to.