Early in 1982, Smith and Wesson (S and W) sent out an advisory outlining a potential problem with its breathalyzer model 1000, stating that it might prove sensitive to RFI. In September, the company issued a second advisory stating that its models 900 and 900A had shown some sensitivity to RFI. S and W recommended that, as a matter of courtroom preparedness, users should follow a particular procedure detailed in its advisory to determine the RFI sensitivity of individual instruments in their working environments. In the Rhode Island case of Durand v. City of Woonsocket, the court granted a statewide injunction prohibiting the use of the model 900A pending regulations by the State Department of Health concerning methods of testing for RFI and acceptable standards of deviations. The judge further enjoined the introduction of breathalyzer results from any machines that have not been tested for RFI as evidence in any pending civil or criminal case. This study did show a high sensitivity of model 900A to RFI. The Model 900A, however, can be inexpensively sealed to make it impervious to RFI. Another approach would be to retain blood or breath samples from original testing to be analyzed later in laboratory controlled conditions by an independent laboratory. Tabular data from the testing of the models are provided.