Diethyl ether interference with infrared breath analysis

Diethyl ether vapor may substantially interfere with breath alcohol analysis by instruments based on infrared absorption at 9.5 microns. Exposure of two volunteers simultaneously to diethyl ether vapor for one hour followed immediately by breath tests on the Draeger Alcotest 7110, Siemens Alcomat V5.2F, and Seres Ethylometre 679T produced apparent alcohol readings in one subject of 0.4, 0.1, and 0.1 g/100 mL of blood respectively. Positive readings persisted in this subject for more than 3 hours. The second subject produced much lower readings of 0.03, 0.01, and 0.00, respectively. Readings persisted with the Alcotest 7110 for one hour. Gas chromatographic analyses of blood and breath samples confirmed that these readings were caused by diethyl ether and not ethanol. The blood concentration of diethyl ether in Subject A immediately after exposure was 25 mg/L. This level produced no clinically detectable neurological changes in the subject.