Archive for November, 2004

“Close Enough for Government Work”

Tuesday, November 30th, 2004

With more than a little federal coercion, all states have now passed laws making it a criminal offense to drive with .08% alcohol in your blood. And most people suspected of violating that law are given breath tests to determine their blood-alcohol concentration (BAC). The breathalyzer will take a small sample of the suspect’s breath and estimate how much alcohol is in it — and, then, estimate how much may be in the blood.

And what that machine says is pretty much the end of it. There will be no second tests. There will be no cross-examination of the machine. Are these machines so reliable and accurate that we have permitted them to become judge and jury?

Scientists universally recognize an inherent error in breath analysis, generally of plus or minus .01%. That means that if everything is working perfectly (an unlikely scenario), a .13% breathalyzer test result can be anywhere from .12% to .14%.This has been acknowledged by courts across the country (see, for example, People v. Campos, 138 Cal.Rptr. 366 (California); Haynes v. Department of Public Safety, 865 P.2d 753 (Alaska); State v. Boehmer, 613 P.2d 916 (Hawaii), recognizing an even larger .0165% inherent error).

What does that tell us about the accuracy of these breathalyzers? Well, let’s take a test result of .10%. Taking inherent error into consideration — and assuming the machine was working perfectly, the officer administers the test correctly, and the suspect’s physiology is normal and perfectly average — the true BAC could be anywhere from .09% to .11%. In other words, the true BAC can be 10% in either direction — or, put another way, anywhere within a 20% margin of error.

These machines have a 20% margin of error?

That’s right. A person accused of driving with over .08% BAC can be convicted by a machine which, if everything else is perfect, has a built-in 20% margin of error. Would you be comfortable with an airline pilot who worked with a 20% range of error? A brain surgeon? A bank teller? How about the sole evidence in a criminal case where guilt must be proven beyond a reasonable doubt?

Close enough for government work.

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How to Fool the Breathalyzer

Saturday, November 27th, 2004

Want to trick that breath machine into a false reading? Not that difficult: just vary your breathing pattern.

As I’ve indicated in earlier posts, these breath machines which determine guilt or innocence in DUI cases are not exactly the reliable devices that law enforcement would have us believe.Yet another example of that unreliability is the fact that the results will vary depending upon the breathing pattern of the person being tested.

This has been confirmed in a number of scientific studies. In one, for example, a group of men drank moderate doses of alcohol and their blood-alcohol levels were then measured by gas chromatographic analysis of their breath. The breathing techniques were then varied.The results indicated that holding your breath for 30 seconds before exhaling increased the blood-alcohol concentration (BAC) by 15.7%. Hyperventilating for 20 seconds immediately before the analyses of breath, on the other hand, decreased the blood-alcohol level by 10.6%. Keeping the mouth closed for five minutes and using shallow nasal breathing resulted in increasing the BAC by 7.3%, and testing after a slow, 20-second exhalation increased levels by 2%. "How Breathing Techniques Can Influence the Results of Breath-Alcohol Analyses", 22(4) Medical Science and the Law 275.For another study with similar findings, see "Accurate Measurement of Blood Alcohol Concentration with Isothermal Breathing", 51(1) Journal of Studies on Alcohol 6.

Dr. Michael Hlastala, Professor of Physiology, Biophysics and Medicine at the University of Washington has gone farther and concluded:

"By far, the most overlooked error in breath testing for alcohol is the pattern of breathing….The concentration of alcohol changes considerably during the breath…The first part of the breath, after discarding the dead space, has an alcohol concentration much lower than the equivalent BAC. Whereas, the last part of the breath has an alcohol concentration that is much higher than the equivalent BAC. The last part of the breath can be over 50% above the alcohol level….Thus, a breath tester reading of 0.14% taken from the last part of the breath may indicate that the blood level is only 0.09%." 9(6) The Champion 16 (1985).

Many police officers know this. They also know that if the machine contradicts their judgement that the person they arrested is intoxicated, they won’t look good. So when they tell the arrestee to blow into the machine’s mouthpiece, they’ll yell at him, "Keep breathing! Breathe harder! Harder!" As Professor Hlastala has found, this ensures that the breath captured by the machine will be from the bottom of the lungs, near the alveolar sacs, which will be richest in alcohol. With the higher alcohol concentration, the machine will give a higher — but inaccurate — reading.

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Alcoholics, DUI and Catch-22

Friday, November 26th, 2004

It may not surprise you to find out that alcoholics arrested for DUI will generally have higher blood-alcohol readings. It may surprise you, however, to learn that alcoholics will generally have higher blood-alcohol readings BECAUSE they are alcoholics….. That’s right. It’s because the physiology of alcoholics is different in some important respects.

One of those is that their bodies produce more acetaldehyde — far more. Acetaldehyde? That’s a compound produced in the liver in small amounts as a by-product in the metabolism of alcohol. Unfortunately, alcohol in the lungs has been found to metabolize there as well as in the liver — and to produce acetaldehyde there.

The amount of acetaldehyde produced in the lungs (to then be breathed into the breathalyzer) varies from person to person. "Origin of Breath Acetaldehyde During Ethanol Oxidation: Effect of Long-Term Cigarette Smoking", 100 Journal of Laboratory Clinical Medicine 908. But in a study focusing on alcoholics, researchers discovered that the amount of acetaldehyde in the breath and blood of alcoholics was 5 to 55 times higher than that in nonalcoholics. "Elevated Blood Acetaldehyde in Alcoholics and Accelerated Ethanol Elimination", 13 (Supp 1) Pharmacology, Biochemistry and Behavior 119.

End result: since breathalyzers can’t tell the difference between alcohol and acetaldehyde (see earlier post, "Why Breathalyzers Don’t Measure Alcohol"), alcoholics will usually have higher blood-alcohol readings.

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Driving a New Car? Don’t take a Breath Test!

Wednesday, November 24th, 2004

Remember that "new car smell"? The great scent inside of that new car you bought a couple of years ago? It could get you charged with DUI…. Consider an excerpt from the Reuters news agency (Sydney, December 9, 2001):

"Australian scientists have warned that the reassuring smell of a new car actually contains high levels of toxic air emissions which can make drivers ill. A study by Australia’s main scientific body, the Commonwealth Scientific and Industrial Research Organization (CSIRO), found high levels of toxic emissions in cars for up to six months and longer after they leave the showroom… The toxic emissions include benzene, a cancer-causing toxin; acetone, a mucosal irritant; ethylbenzene, a systemic toxic agent; and xylene isomers, a foetal development toxic agent…."

So what has this got to do with breath tests? Well, one of the compounds you were actually smelling was acetone. As has been discussed in earlier posts ("Why Breathlyzers Don’t Measure Alcohol"), acetone is one of many chemical compounds which Breathalyzers will mistakenly report as alcohol. See the reasearch reported in such scientific articles as "The Likelihood of Acetone Interference in Breath Alcohol Measurements", 3 Alcohol, Drugs and Driving 1, and "Excretion of Low-Molecular Weight Volatile Substances in Human Breath: Focus on Endogenous Ethanol", 9 Journal of Analytical Toxicology 246.

And no, you don’t have to drink the stuff. Simply absorbing it through your skin or inhaling it can result in measurable levels of the compound in your body for hours or even days, which will be continually expelled in the breath….. and possibly into a judge-and-jury breathalyzer.

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Driving Under the Influence of…Gasoline?

Tuesday, November 23rd, 2004

Folks who have read my recent post, "Why Breathalyzers Don’t Measure Alcohol", seem quite surprised to find out these DUI machines are not as reliable as MADD and law enforcement agencies would have us believe. In fact, the manufacturers of these things refuse to even warrant them to do what they’re supposed to: accurately measure blood-alcohol levels (see my earlier post, "Breathalyzers: Why Aren’t They Warranted to Measure Alcohol?")

So how reliable are these "breathalyzers" that determine a person’s guilt or innocence in DUI cases? And just what DO they measure?

Well, thousands of different chemical compounds, according to scientists. Gasoline for one. Consider an article appearing on the front page of the Spokane Spokesman-Review (August 24, 1988), in which a person sitting in jail awaiting trial for DUI claimed that he had nothing to drink. He said he had run out of gas and had been siphoning gasoline from a container into his tank before being stopped by the officer and arrested. In siphoning, he had sucked on the hose to get it started and accidentally swallowed a small amount of the gasoline. He claimed that this must have caused the later high breathalyzer reading. The individual finally talked the sheriff into a demonstration to prove his story.

Taken from his cell after one week of incarceration, he swallowed a cup of unleaded gasoline and then blew into the breath machine — in this case, an "Intoximeter 3000". The results? After 5 minutes, the reading was .00%…..after 10 minutes, .04%……after 20 minutes, the Intoximeter registered .31%…..and after one hour, the reading was .28%. Even after three hours, the person still blew a .24% on the machine — three times the legal limit! (A quick call from the sheriff to a local gasoline distributor confirmed that gasoline contains no alcohol.)

This was not a freak occurrence. The results have been scientifically verified in a study conducted by CMI, Inc., the manufacturer of a competing breath machine, the "Intoxilyzer 5000", and reported in 8(3) Drinking/Driving Law Letter 6. The CMI technicians mixed a simulator solution of 800 micrograms of gasoline with 500 milliliters of distilled water, then introduced it into their machine. The solution produced readings of .619%, .631% and .635% — or about eight times the legal limit for "alcohol" levels.

You don’t have to drink gasoline to get a reading on the breathalyzer. Breathing the fumes will do it. Like at a gasoline pump.

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