•1970’s -1996 EPA audited
 gases
 •Posted results
 –In 1995, one vendor off by
 -16.3% (CEM would underreport)
 •Strong utility and vendor
 support
 •Auditing strongly
 correlated with improved gas quality
 •Audit discontinued after
 1996 due to budgetary constraints
 •Audit reinitiated in
 2003
 •