North Carolina’s DWI enforcement relies heavily on evidentiary breath tests to determine whether a driver’s blood alcohol concentration (BAC) exceeds the legal limit. While officers may perform
This article explains the significance of evidentiary breath tests, how the Intoximeter EC/IR II functions, and why an attorney might challenge its results in certain circumstances. If you have questions about your DWI case or want help reviewing a breath test procedure, call or text the Powers Law Firm at 704-342-4357, or email Bill Powers at Bill@CarolinaAttorneys.com.
Understanding Breath Testing: Table of Contents
- Why Evidentiary Breath Tests Matter
- Introduction to the Intoximeter EC/IR II
- The Mandatory Observation Period
- Chemical Analysis Rights in North Carolina
- Calibration and Maintenance Records
- Refusal vs. Cooperation
- Defense Challenges to Breath Test Results
- Protecting Your Rights: Next Steps for a DWI Defense
1. Why Evidentiary Breath Tests Matter
In North Carolina, a conviction for Driving While Impaired (DWI) can stem from multiple forms of evidence: officer observations, field sobriety tests, blood draws, or admissions by the person accused of impaired driving. Among these, the evidentiary breath test holds a special place because it provides a numeric measurement of a driver’s BAC. Under N.C. General Statute § 20-138.1, driving with a BAC of 0.08 or higher is unlawful for standard license holders (stricter levels apply for commercial drivers and motorists under the age of 21).
The reason these official breath tests matter is that prosecutors often anchor their case to the reading, arguing that it establishes “per se” impairment. If the machine shows 0.08 or higher, the state can argue the driver violated the “per se” DWI provision. Even if the reading is below 0.08, the prosecution can still attempt to prove impairment through other means (like poor driving or failing SFSTs), but a reading at or above the legal limit simplifies their burden significantly.
Further, the North Carolina implied-consent law (G.S. 20-16.2) sets forth that once you’ve been arrested for an implied-consent offense, you are presumed to consent to a chemical test. The official breath test stands as the primary method in many jurisdictions, especially when no complicating factors (like hospital transport or suspected drug impairment) may involve a blood draw. It’s important to note that law enforcement can choose the method of testing. They are not limited to breath tests. As such, in their discretion and consistent with N.C.G.S. 20-16.2, they may request blood, breath, or urine tests.
2. Introduction to the Intoximeter EC/IR II
The Intoximeter EC/IR II is North Carolina’s preferred device for evidentiary breath testing. (*Other devices are approved but rarely, if ever, used to determine BAC in North Carolina DUI cases). The EC/IR II relies on a combination of infrared (IR) and electrochemical (fuel cell) sensors to measure ethanol content in a driver’s alveolar (deep-lung) breath. It is typically stationed in a secure room at a law enforcement facility or intake center, where the environment is controlled to reduce contamination or interference.
Key Features of the Intoximeter EC/IR II:
- Infrared Beam: As a driver exhales, IR sensors detect how much ethanol absorbs the beam, correlating to BAC.
- Fuel Cell: A chemical reaction in the fuel cell sensor also measures ethanol, offering a secondary reading. This dual-sensor approach is thought to improve accuracy.
- Printer & Display: After a test, the machine prints a ticket showing the BAC and other test details, which become part of the DWI case file.
- Internal Self-Checks: The device runs diagnostics and may prompt error messages if it detects anomalies (e.g., calibration errors, residual mouth alcohol, ambient alcohol, inconsistent numerical readings).
Officers operating the machine undergo Intoximeter training, learning to set up the test, observe the subject, and record results. They are referred to as a Licensed Chemical Analyst. Defense lawyers may review the machine’s maintenance logs, to see if everything was done right.
3. The Mandatory Observation Period
Before administering the test, North Carolina law requires a 15-minute observation period, intended to minimize the risk of mouth alcohol or foreign substances that could inflate the BAC reading. For instance, if a driver belches, vomits, or has gum in their mouth, residual alcohol might skew the result.
Officer Responsibilities during observation may include:
- Ensuring the driver does not place anything in their mouth (food, gum, tobacco).
- Watching for regurgitation or spitting.
- Keeping the subject in view to confirm no substances are introduced.
If the officer fails to properly monitor the suspect or restarts the observation period after a potential mouth-alcohol event, the test’s validity could be problematic. A Motion to Suppress might involve an LCA – Licensed Chemical Analyst who failed to comply with the statutory and operational requirements of the device and/or left the subject unattended, possibly calling into question the admissibility of test results. Each case is different. If you have questions about the specifics of your legal matter, consult legal counsel.
4. Chemical Analysis Rights in North Carolina
Once an officer has probable cause to arrest for DWI, the subject is taken to a location where the Intoximeter EC/IR II is available. At that point, implied-consent rules require the officer to inform the driver of specific rights, often called “chemical analysis rights.”
N.C. Gen. Stat. § 20-16.2(a) requires the officer to explain:
- You’re entitled to consult with an attorney and have a witness present during the test (though the process cannot be unreasonably delayed).
- Possible consequences of refusing to blow (or provide another type of sample, such as blood, to determine BAC and/or appreciable impairment) include a 12-month civil revocation of your license.
- If the test shows a BAC of 0.08 or higher, you may face immediate license restrictions under 20-16.5.
You generally have up to 30 minutes after being informed of these rights to contact a lawyer or witness. If a friend or attorney is en route, the officer may be required to wait unless that extends beyond the thirty-minute period. Defense lawyers sometimes attack BAC test results depending on the unique facts and circumstances of the case. It’s a notoriously complicated and technical aspect of DUI defense. That might include the failure to properly provide the implied consent rights or cutting short the 30-minute window prematurely, contrary to statutory requirements.
5. Calibration and Maintenance Records
The Intoximeter EC/IR II, like any breath-testing device, must be calibrated and maintained regularly. North Carolina Administrative Code policies outline how often the simulator solutions or gas cylinders must be changed, how logs are updated, and what steps the operator must take if the machine fails to operate properly.
Why These Logs Matter:
- Accuracy Over Time: If the machine drifts out of calibration, readings may become unreliable. Defense attorneys sometimes review calibration logs to see if checks were done on schedule.
- Standard Operating Procedures (SOP): Officers should follow each step before running a subject’s breath sample. Skipping steps can reduce confidence in the result.
- Error Messages: Sometimes the machine displays codes indicating issues.
6. Refusal vs. Cooperation
Under N.C. Gen. Stat. § 20-16.2, refusing the evidentiary breath test triggers a Willful Refusal and related license revocation. You have a right to refuse, but it comes with significant consequences:
- Immediate “Refusal” Notation: The officer indicates you declined the test after implied-consent warnings.
- DWI Charge Still Possible: An arrest can proceed based on other evidence (like driving behavior, odor of alcohol, or field sobriety tests).
- Negative Inference: Prosecutors may argue your refusal suggests you feared a high BAC reading.
However, cooperating is no guarantee you’ll avoid a charge. If the reading is at or above the 0.08 limit, the state now has a strong piece of evidence. Drivers sometimes hope a low reading (below 0.08) will prevent charges, but officers may still charge DWI if they believe the subject is appreciably impaired.
7. Defense Challenges to Breath Test Results
Defense attorneys sometimes review the different steps of a breath test procedure to see if any technical or procedural issues may have influenced the reported BAC. Possible areas of inquiry include:
- Observation Period: If the officer left the driver alone or did not confirm whether substances (like gum or regurgitated material) might affect the reading, that could, in appropriate circumstances, raise questions about mouth alcohol.
- Operator Training: Records or credentials may be examined to see if the person administering the test was adequately trained or had the appropriate certifications for the Intoximeter EC/IR II.
- Calibration Logs & Simulator Solutions: If the machine was not serviced as recommended, that could affect reliability.
- Health Conditions or Medications: Certain conditions or substances might interact with breath-testing technology, potentially influencing the reading.
- Machine Issues: Although rare, malfunctions or error messages might suggest the need for additional scrutiny.
Whether any of these concerns affect a specific case depends on the circumstances. Legal challenges can vary in their impact, and no single factor necessarily invalidates a result on its own.
8. Protecting Your Rights: Next Steps for a DWI Defense
Intoximeter EC/IR II breath test results are clearly an important consideration in any DWI case in North Carolina. At the same time, preparing a defense strategy involves more than focusing solely on the BAC. Each set of facts may warrant examining how the stop was initiated, whether procedures were followed, whether reasonable suspicion and probable cause existed, and if any mechanical or health-related issues affected the reported BAC. Reviewing maintenance records, verifying that the observation period, and confirming that chemical analysis rights were explained are just a few ways a DUI defense attorney might evaluate the evidence. If you want to learn more about the breath testing process or discuss your specific circumstances, please call or text the Powers Law Firm at 704-342-4357, or email Bill Powers at Bill@CarolinaAttorneys.com.