Archive for March, 2011

When Is Alcohol Not Alcohol?

Friday, March 18th, 2011

Breathalyzers don’t actually measure alcohol.

That’s right.  What these machines actually detect and measure is any chemical compund that contains the methyl group in its molecular structure. There are thousands of such compounds — including quite a few which can be found on the human breath. And this machine that determines a person’s guilt or innocence will “see” all of those chemicals as alcohol — and report a falsely high “blood-alcohol” concentration (BAC).

Most breath machines used by law enforcement in DUI cases today employ a technology called infrared spectroscopy. The DUI suspect breathes through a tube connected to the machine and a breath sample is captured in a small sample chamber inside the machine. Then beams of infrared light are shot through the captured breath sample. If there are any compounds containing the methyl group, they will absorb some of this light; the more of the chemical compound in the breath sample, the more light is absorbed. The more light that is absorbed, the less that reaches sensors at the other end of the sample chamber. And the less light that is detected by the sensors, the higher the supposed “blood-alcohol” reading.

Problem: the machines are, scientifically speaking, fairly unsophisticated. They are, as scientists say, non-specific — that is, they are not capable of detecting and measuring a specific compound (such as ethyl alcohol).  

More important for government work, they are relatively cheap.  Rather than use more expensive filters and/or multiple filters, for example, most breathalyzers use a lesser number of less-costly filters.  Result:  these machines can only detect and measure a broad range of compounds containing the methyl group — and they then simply assume that the unknown compound within this group is ethyl alcohol.

If a person has any of these other compounds on his breath, called interferents by the scientists, he will get a falsely high breath alcohol test result. And if there are two or three such compounds on his breath, the machine will read and report a cumulative result: it will add them up and falsely report the total as the level of alcohol in the breath.

So what kinds of compounds may be on a person’s breath that can cause false BAC readings in a DUI case? In one study of eight men, 69 different compounds containing the methyl group were discovered.  “Trace Composition of Human Respiratory Gas”, 30 Archives of Environmental Health 290.  In another study invoviing 28 subjects, researchers found that the “combined expired air comprises at least 102 various organic compounds of endogenous and exogenous origin”.  “Characterization of Human Expired Air”, 15 Journal of Chromatographic Sciences 240.  And Canadian scientists have discovered over 200 such compounds.  “The Diagnostic Potential of Breath Analysis”, 21(1) Clinical Chemistry 5.

What are these compounds?  Are there any on my breath?  Well, for starters, diabetics with low blood sugar can have high levels of acetone — which is “seen” as alcohol by breathalyzers. And scientific studies have found that people on diets can have reduced blood-sugar levels, causing acetone hundreds of times higher than found in normal individuals. Frank and Flores, “The Likelihood of Acetone Interference in Breath Alcohol Measurements”, 3 Alcohol, Drugs and Driving 1. And there are many other so-called “interferents”. See, for example, “Excretion of Low-Molecular Weight Volatile Substances in Human Breath: Focus on Endogenous Ethanol”, 9 Journal of Analytical Toxicology 246.

If you are a smoker, your breathalyzer result is likely to be higher than expected. The compound acetaldehyde — reported by the breathalyzer as “alcohol” — is produced in the human body as a by-product in metabolizing consumed alcohol, and eventually passes into the lungs and breath. Researchers have discovered that levels of acetaldehyde in the lungs can be 30 times higher in smokers than in non-smokers. Result: higher BAC readings on the machine.

And then there are the industrial compounds: paint, glue, gasoline, thinners, and other compounds contain the methyl group. No, you don’t have to drink the stuff: simply absorbing it through your skin or inhaling the fumes can result in significant levels of the chemical in your body for hours or even days, depending upon the half-life of the compound. So if you’ve painted a room or been around gasoline in the last day or two, don’t breath into a breathalyzer.

Some law enforcement officials say that this is not a problem, claiming that levels of the compound would have to be at toxic levels to raise a breath test result to .08% or higher. These officials are displaying their ignorance of the science involved — specifically, of the partition ratio. This is the ratio of the compound found in the breath to that found in the blood. With ethyl alcohol, the ratio is 2100-to-1, which means that, on average, there will be 2100 units of alcohol in the blood for every unit found in the breath. These officials are using this ratio for all compounds, but every compound has its own ratio. Toluene (found in paint, glue, thinners, cleaning solvents. etc.), for example, has a partition ratio of only 7-to-1; a far greater amount of toluene in the blood will pass into the breath, and so a much smaller amount in the body will have a far greater impact on the breath machine.
Oh well, close enough for government work, right?


What Happens If the Cops Refuse to Give You a Blood Test?

Tuesday, March 15th, 2011

When the police administer a breathalyzer, the suspect’s breath sample is analyzed — and then destroyed by purging it into the air. Although it is easy and inexpensive to save the sample so that it could later be independently analyzed by the defense, the U.S. Supreme Court in California v. Trombetta ruled that there is no right to this. (See "Why Do Police Destroy the Evidence in DUI Cases?".)

Recognizing that an accused should have some minimal rights even in a DUI case, many states have enacted laws requiring the police to advise the suspect that he has the right to have an independent blood sample drawn so that it may be later analyzed and compared to the breath test results. California’s Vehicle Code Section 23614 is an example:

(a) ….a person who chooses to submit to a breath test shall be advised before or after the test that the breath testing equipment does not retain any sample of the breath and that no breath sample will be available after the test which could be analyzed later…

(b) The person shall also be advised that, because no breath sample is retained, the person will be given an opportunity to provide a blood or urine sample that will be retained at no cost to the person so that there will be something retained that may be subsequently analyzed for the alcohol content of the person’s blood. If the person completes a breath test and wishes to provide a blood or urine sample to be retained, the sample shall be collected and retained in the same manner as if the person had chosen a blood or urine test initially. [italics added]

Sounds fair. Except officers don’t like handling a suspect’s urine or spending an hour or so finding a blood technician to draw a sample. Result: this law is commonly ignored by the police. (Some DUI report forms contain a place for the officer to indicate that he advised the suspect of the right to an independent test, and it is commonly checked off — and ignored.)

So what can a defendant do if this legal right is violated? Well, the statute clearly says "shall" advise and collect: it is mandatory, not optional. It would seem to follow that there would be some legal sanction for a willful refusal to follow this law — the only meaningful one being suppression of the breath test.

Wrong. Remember: this is a DUI case we’re dealing with. If you look closely, another little provision at the end of California’s statute adds the following:

(d) No failure or omission to advise pursuant to this section shall affect the admissibility of any evidence of the alcohol content of the blood of the person arrested.

Cute, no? The law gives you a "right", and then makes it unenforceable. It is, as we lawyers say, "a right without a remedy". And, of course, since there are no consequences for ignoring this advisement of the right to an independent test, most officers continue to ignore the law. Practically speaking, then, officers do not have to follow the law and advise the suspect of his right to an independent test.

There are some court decisions, however, which seem to say that interfering with attempts by the arrested person to have blood drawn may be grounds for suppression of the breath test. See, e.g., In re Martin, 58 Cal.2d 509. And many states will suppress breath test results if the police refuse to permit the suspect to obtain a blood sample. In State v. George, 754 P.2d 460, for example, the Kansas court ruled that breath results should have been suppressed where the arresting officer refused a suspect’s request for an independent test because of the time required to transport him to a hospital and find a physician.

Bottom line:  yes, you have an absolute legal right to a blood sample…except, well, you don’t. 


High Blood-Alcohol?….or Zinc Deficiency?

Friday, March 4th, 2011

So you only had two beers, but the breathlyzer read .11%. What happened? Well, for starters, breath machines are generally inaccurate and unreliable. Then again, maybe you had a dietary deficiency. Scientific research appears to indicate that a high blood-alcohol level may not reflect high alcohol consumption, but rather a deficiency of zinc in the blood.

In a study conducted at the University of North Dakota, researchers discovered that the metabolism of alcohol was dramatically affected by zinc intake. For example, they found that for those subjects on a low zinc diet, blood-alcohol levels increased rapidly within 15 minutes of consumption of measured amounts of alcohol: roughly twice as much alcohol was present in their blood as was present in those subjects on normal zinc diets. Further, greater amounts of alcohol remained in the blood for longer periods of time when there was a zinc deficiency. 46 American Journal of Clinical Nutrition 688.

Interestingly, it has been discovered that individuals who regularly consume large amounts of alcohol develop zinc deficiencies. This deficiency will, of course, cause the higher alcohol concentration and slower elimination. In other words, it is the problem drinker who is most likely to have abnormal absorption and elimination of alcohol — and abnormally high blood-alcohol test results.