Challenging the Intoxilyzer 9000: How to Fight DWI Breath Test in Texas

The rise in DWI cases across Texas has brought increased scrutiny to the state’s primary breath testing instrument, the Intoxilyzer 9000. While prosecutors often present breath test results as ironclad evidence, several critical vulnerabilities exist that create compelling opportunities for challenge. This article explores the most significant issues with Texas’ implementation of the Intoxilyzer 9000 and how these weaknesses can impact DWI cases.

Texas Breath Alcohol Testing Regulations and Oversight

Texas has a long history of regulating breath alcohol testing procedures. Texas initiated breath alcohol testing in the late 1940s, but statewide implementation began in 1968 with the Breathalyzer. The program gained statutory authority through the 1969 Implied Consent Law, which empowered the Department of Public Safety to establish and oversee breath testing protocols. In 1969, the Texas Legislature established the Texas Breath Alcohol Testing Regulations. To administer and enforce these regulations, the Texas Department of Public Safety created the Office of the Scientific Director. This office oversees all evidential breath analyses conducted by state, county, and city law enforcement agencies. The current legal framework defines intoxication in Chapter 49 of the Texas Penal Code using two distinct standards: loss of normal mental or physical faculties, or an alcohol concentration of 0.08 or greater (measured as grams of alcohol per 210 liters of breath).

Currently, these tests are performed in over 370 approved facilities in Texas by approximately 6,000 certified breath test operators, representing around 700 different law enforcement agencies. These operators must follow strict protocols to ensure the reliability of the results.

The Role of the Scientific Director and Technical Supervisors

The Scientific Director approves and certifies all breath alcohol testing instruments used in Texas for evidential purposes. A list of approved instruments is kept, and any new or modified instruments are evaluated by the Scientific Director before being accepted.

Technical Supervisors are qualified forensic scientists certified by the Scientific Director. They serve as the Scientific Director’s representatives in all matters related to breath alcohol testing. Their main duties include providing technical, administrative, and supervisory expertise to protect the scientific integrity of Texas’ breath alcohol testing program. Technical Supervisors, who must possess a baccalaureate degree in chemistry or related science, oversee operations in their assigned areas.

Breath Test Operators are individuals certified by the Scientific Director to conduct evidential breath alcohol analyses for law enforcement. The Office of the Scientific Director has created detailed training standards and curricula for operator certification. Operator certification requires initial training, regular renewal, and maintenance of proficiency through ongoing testing. Notably, operators must complete any combination of five subject or practice tests between certification periods and undergo biennial instruction with written examination.

Approval Criteria for Evidential Instruments

According to the regulations, all evidential breath testing instruments in Texas must meet specific criteria, including:

• Analyzing expired breath specimens accurately.
• Using a reference system with results that agree within ±0.01 g/210L of the stated value (or other limits set by the Scientific Director).
• Ensuring the procedure’s specificity is sufficient to accurately measure alcohol concentration in a law enforcement setting.
• Successfully passing any additional tests deemed necessary by the Scientific Director to ensure correct, reliable results for law enforcement purposes.

Once an instrument meets these requirements, it is placed on the Scientific Director’s approved list. However, approval can be rescinded for cause if the instrument no longer meets the necessary standards. Technical Supervisors are tasked with confirming that a specific instrument’s serial number matches one on the approved list and that it continues to meet the certification criteria. If issues arise, the Scientific Director or a designated representative can remove the instrument from evidential testing.

Intoxilyzer 9000 in Texas

The Intoxilyzer 9000 operates on the principle of infrared spectrometry. This technology measures alcohol concentration by analyzing how ethanol molecules absorb infrared energy at specific wavelengths. The instrument’s use of multiple wavelengths ensures specificity for ethyl alcohol, distinguishing it from other substances that might be present in breath samples. The system includes calibration verification processes, requiring results between 0.070 and 0.090 g/210L for accuracy validation.

Operational Protocols and Critical Requirements

Several critical protocols govern the proper operation of the Intoxilyzer 9000. Perhaps most crucial is the mandatory 15-minute observation period before testing, during which a certified operator must continuously monitor the subject to ensure no substances enter the mouth. This waiting period prevents contamination from residual mouth alcohol, which could skew results.

The testing sequence follows a strict protocol including:

• Operational system checks
• Air blank analyses
• Multiple subject breath samples
• Calibration verifications
• Solution temperature monitoring

Issues that Can Compromise Intoxilyzer 9000 Results

Several issues can compromise test validity or operator certification. These include:

1. Failure to maintain proper observation during the 15-minute waiting period
2. Calibration verification results outside acceptable ranges
3. Reference sample temperatures beyond the 33.8°C – 34.2°C specification
4. Operator certification lapses due to missed renewal deadlines
5. Interference from substances like acetone in diabetic subjects

When protocols are not followed, consequences can be significant. Tests may be invalidated, and operators may face certification suspension for a minimum of 30 days. Critically, the presence of interfering substances requires immediate test termination, and subjects cannot be retested under such circumstances.

The Missing Histogram: A Critical Gap in Scientific Validation

Perhaps the most glaring issue with Texas’ deployment of the Intoxilyzer 9000 is the state’s deliberate decision to forego the histogram function. This isn’t just a minor feature omission—it represents the absence of a crucial scientific safeguard that other states consider essential for validating breath test results.

Why the Histogram Matters

The histogram function provides real-time graphical data of breath samples, offering vital information about breath flow rate, volume patterns, and alcohol concentration throughout the sample. This visual representation serves as a quality control mechanism, allowing technicians to spot irregular breathing patterns, detect mouth alcohol contamination, and verify proper sample collection. Without this feature, Texas law enforcement lacks a key tool for ensuring the accuracy and reliability of breath test results.

In other jurisdictions, such as Florida, courts rejected breath test evidence when Intoxilyzer 8000 machines showed airflow issues leading to incorrect results. Some states even banned breath test evidence until proper verification features were installed. Texas’ choice to operate without this critical verification mechanism raises serious doubts about the scientific reliability of its breath testing program.

Infrared Detection Limitations

The shift to measuring carbon-oxygen (C-O) vibrations in the 9-micron region, rather than carbon-hydrogen (C-H) bonds at 3 microns, introduces new complications in breath analysis. This fundamental change in detection methodology creates several potential problems:

The device can be affected by multiple common substances that share similar molecular structures:

• Dimethyl Sulfoxide (DMSO), commonly used in medical treatments
• Diethyl ether, present in many industrial solvents
• Various esters used in food flavoring
• Industrial chemicals with similar molecular bonds

COVID-19’s Lasting Impact on Reliability

The COVID-19 pandemic added another layer of complexity to breath testing reliability in Texas. Before April 2020, the Department of Public Safety required monthly in-person inspections, regular calibration checks, and physical verification of testing environments. When these requirements were suspended during the pandemic, however, many counties never fully returned to their previous protocols.

Maintenance Gaps Under the Kelly Standard

This deviation from standard maintenance procedures poses major legal vulnerabilities under the Kelly standard, which requires prosecutors to prove the validity of the underlying scientific theory and its proper application. Without consistent in-person maintenance, questions arise about whether breath testing is being applied correctly and in line with scientific principles.

Physical inspections and calibration checks are vital for establishing that a machine is in proper working order—an essential requirement for admitting scientific evidence. When these steps are skipped or done remotely, it opens the door to legal challenges, ranging from basic hearsay objections to confrontation clause issues under Melendez-Diaz v. Massachusetts.

Scientific Reliability and Quality Control

Beyond procedural flaws, the combination of missing features and reduced maintenance raises broader concerns about scientific reliability. Proper scientific practice demands controls, verification steps, and thorough documentation to confirm accurate results. Texas’ Intoxilyzer 9000 program lacks many of these safeguards.

Without the histogram function, technicians cannot confirm proper breath sample collection or detect contaminants like mouth alcohol. Reduced in-person maintenance further increases the risk that errors or malfunctions might go unnoticed for long stretches of time.

Building an Effective Challenge Strategy

Challenging breath test evidence effectively requires addressing both technical and legal weaknesses. Defense attorneys should seek out complete maintenance records, particularly for the periods when maintenance procedures were altered. Comparing pre-COVID and post-COVID protocols can uncover significant differences in quality control.

Cross-examining technical supervisors is also crucial. By asking detailed questions about their knowledge of machine condition, how remote inspections were conducted, and the basis for declaring the machine in good working order, attorneys can expose gaps in the foundation for breath test evidence. These gaps support various legal challenges, from Kelly reliability to constitutional violations.

The Future of Breath Testing in Texas

As DWI cases continue to rise, questions about the Intoxilyzer 9000’s accuracy may push Texas to revisit its breath testing procedures. The interaction between limited verification features and scaled-back maintenance has created risks that courts may no longer be willing to overlook.

This situation also prompts larger questions about balancing law enforcement goals with scientific reliability. While breath testing is important for public safety, the current Texas system seems to favor convenience over accuracy. Omitting key verification features and reducing maintenance threatens the integrity of criminal prosecutions.

Conclusion

These concerns over Texas’ Intoxilyzer 9000 go far beyond small technical details—they challenge the core of scientific reliability and constitutional rights in DWI cases. Missing features like the histogram function and scaled-back maintenance during COVID-19 create powerful reasons to doubt the breath test’s accuracy.

Defense attorneys who understand these issues have a solid opportunity to challenge the admission of breath test results. By highlighting how the Intoxilyzer 9000 falls short of accepted scientific standards and legal requirements, they can protect their clients’ rights and push for needed reforms.

Ultimately, these challenges could prompt Texas to adopt more rigorous verification tools and stricter maintenance protocols for breath testing instruments. Until then, recognizing and leveraging these vulnerabilities remains critical for ensuring justice in DWI cases.

Read More:

The New York Times: These Machines Can Put You in Jail. Don’t Trust Them.

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