Intoxilyzer 5000 in need of maintenance. 100 alcohol standard at 34 C. Exposure to mixture of room temperature 50 alcohol standard and GOJO containing limonene bubbled into breath tube during air blanks plus GOJO on hands near flask air entry. After initial AMBIENT FAIL ACACA cal. checks now reading as low as 62 mg/100mls or even lower if INTERFERENT flag at 24 mgs/100mls. 0 has been raised by ethanol and limonene during air blanks far above 20 mg/100 mls threshold. In the process GOJO/limonene has either contaminated sample chamber, tubing, simulator or 100 alcohol standard or instrument's interferent add/subtract circuitry has been affected ultimately result in in 145 cal. check and 144 cal. check when room air used as ambient. Quaere: does contamination of an instrument and accesory equipment by an ambient interferent necessitate a change to the alcohol standard? Is it therefore necessary that the police log and the Crown disclose every "INTERFERENT" error (cards and COBRA/ADAMS) since the last solution change and prior to the subject test so that the defence will have full notice that the alcohol standard may have been unreliable? Intoxilyzer® is a registered trademark of CMI, Inc. The Intoxilyzer® 5000C is an "approved instrument" in Canada.