I would affirm the district court’s dismissal of Veazey’s complaint. I have no quarrel with this court’s thorough analysis of the shortcomings of polygraphs and their fallibility when used as evidence of truthfulness. But Veazey’s assertion that a tape recorder qualifies as a lie detector has no foundation under the terms of the Employee Polygraph Protection Act, 29 U.S.C. § 2002(3), and simply using a tape recorder to compare voice samples does not violate the Act.
EPPA restricts certain employers from administering lie detector tests to their employees. 29 U.S.C. § 2002(3).1 The statute defines the term “lie detector” as including “a polygraph, deceptograph, voice stress analyzer, psychological stress evaluator, or other similar device (whether mechanical or electrical) that is used, or *862the results of which are used, for the purpose of rendering a diagnostic opinion regarding the honesty or dishonesty of an individual.” 29 U.S.C. § 2001(3). Thus, the EPPA prohibits the use of devices which are designed to determine whether particular assertions or answers to questions are true or false, and nothing more. Accordingly, LaSalle could not have used a voice stress analyzer on a tape recording of a statement by Veazey to determine whether the contents of the recorded statement were true or false. But the Act does not prohibit employers from using other investigative techniques to identify employees who may have violated criminal laws or company regulations. Therefore, the district court correctly held that the EPPA does not prevent employers from seeking voice samples from an employee suspected of leaving harassing messages on another employee’s voicemail, in order that the employer might compare the voices. Since Veazey has not claimed that any recording would have been subjected to a stress analyzer, his complaint cannot survive a 12(b)(6) dismissal.
Veazey does assert that the term “lie detector” includes a tape recorder, and that EPPA therefore prohibits LaSalle from firing him for failing to submit a recorded voice sample. See Complaint ¶ 17. Notably, Veazey provided neither statutory nor case law support for this assertion. “When construing a statute, we must first look to the language used by Congress, giving the words their ordinary meaning. ‘[Ajbsent a clearly expressed legislative intention to the contrary, that language must ordinarily be regarded as conclusive.’ ” United States v. Wilson, 159 F.3d 280, 291-92 (7th Cir.1998) (quoting American Tobacco Co. v. Patterson, 456 U.S. 63, 68, 102 S.Ct. 1534, 71 L.Ed.2d 748 (1982)). Veazey’s interpretation is clearly at odds with the statute’s definition of the term “lie detector,” as a tape recorder is not one of the devices which the statute specifically proscribes. Furthermore, merely recording a voice or comparing recorded voices does not result in a “diagnostic opinion” regarding the honesty or dishonesty of the individual as the term is defined by the statute. Unless subjected to the statutorily forbidden “voice stress analyzer,” the tape recording of his voice is permissible. A plain reading of the statute thus does not support Veazey’s interpretation.
Because the term “lie detector” means devices such as polygraphs, decepto-graphs, and voice stress analyzers, and a tape recorder is not similar to these devices (it records sounds; it does not analyze the sounds), a tape recorder cannot be a lie detector as the term is defined by the statute.2 Therefore, an employer may terminate an employee for refusing to provide a voice sample for purposes of comparative analysis without violating the EPPA, much like an employer may terminate an employee for failing to provide a urine sample for a drug test. Gonzalez v. Ingersoll Milling Mach. Co., 133 F.3d 1025, 1034 (7th Cir.1998) (under the employment at-will doctrine an employee may be fired for any reason that does not violate law or public policy); see Slane v. Mariah Boats, Inc., 164 F.3d 1065, 1066 (7th Cir.1999) (employer claimed that it fired employee for failing to provide a urine sample).3 As with a urine sample, a tape-recorded voice sample will require further analysis. If a *863person claims he is drug-free, a positive urine test will prove he is lying. Similarly, if a person claims a recorded threat is not his voice, but a comparative voice graph shows the threatening voice was his, he is lying. But the mechanical devices used to analyze -the data in the urinalysis or voice analysis are not “similar devices” to the polygraph, the voice stress analyzer, or the other examples of lie detectors set out in the statute. Accordingly, employers may legitimately use tape recorders in ferreting out sexual harassment or other violations of law or company policy. They merely must refrain from subjecting those recordings to lie detector tests, such as a voice stress test.4 Because Veazey’s complaint does not allege that LaSalle was attempting to do anything other than a comparative analysis, the district court correctly found that he failed to state a claim under EPPA.
. Despite believing that polygraphs were unreliable, Congress exempted from the EPPA federal, state, and local governments, private security services, drug manufacturers, and other employers. See 29 U.S.C. § 2006.
. This interpretation is also consistent with the canon of statutory construction ejusdem generis. " 'Under the principle of ejusdem generis, when a general term follows a specific one, the general term should be understood as a reference, to subject akin to the one with specific enumeration.” " Newsom v. Friedman, 76 F.3d 813, 820 (7th Cir.1996) (quoting Norfolk & Western Ry. Co. v. American Train Dispatchers' Ass'n, 499 U.S. 117, 129, 111 S.Ct. 1156, 113 L.Ed.2d 95 (1991)). Thus, in the present case, the statute's general term "any other similar device” must be read in conjunction with the explicit list of devices. Needless to say, a tape recorder is hardly similar to a polygraph or voice stress analyzer.
. To prevent any argument on the matter, the regulations interpreting the EPPA specifically state that the Act does not preclude medical tests to determine the presence of alcohol or controlled substances in blood or urine. 29 C.F.R. § 801.2(d).
. Generally, in voice stress analysis, a person is asked a series of questions by an examiner. Because stress causes microtremors in the muscles around the larynx, the stress purportedly induced by lying may be discernable in the examinee's voice. The examiner records the responses on an audio stress analysis instrument which computes and displays a chart of the level of the examinee's stress. The chart is then analyzed to determine if and when the subject lied. .
In this case, however, Veazey was asked to read a transcript, and not to answer questions. It is doubtful, then, whether LaSalle could have conducted a voice stress analysis on Veazey’s voice sample, which contained no assertions that could be measured for truth.