A site block is automatically placed on a cardholders profile if the cardholder blows a non-negative result on a site associated Blood Alcohol Concentration Breathalyser device. 

Site blocks can only be removed by an Employer, Project or Site Administrator following the result of a second confirmatory test, and where the second confirmatory test records as negative.  If the second confirmatory test results in a confirmed positive, then a Network Operator block will be placed.