The California State Board of Equalization is auditing California medical marijuana dispensaries and ordering many to pay sales tax on sales of marijuana products that the businesses did not collect from patients or pay to the state.   The Berkeley Patients Group did not start collecting and paying sales tax until 2007 and now the “State Board of Equalization  is ordering the Berkeley facility to pay $6.4 million in back taxes and interest on $51 million in pot sales between 2004 and 2007.”