How Does Drug Purity Impact Criminal Sentencing?

If you were asked to consider what factors play a major role in criminal penalties for non-violent drug offenses, what would come to mind? You may already know that drug possession for personal use is a less serious crime than running an illegal business selling drugs. You may also know that larger quantities of drugs can result in more serious penalties. Finally, you may have some idea of how different types of drugs are placed in different ‘drug schedules’, where unlawful possession of distribution of one type can be a more serious crime than another type. Another factor that plays a significant role in sentencing, but can often be overlooked, is drug purity. In this article we explore what it means for a drug to be considered pure, how that impacts criminal sentencing, and what issues this approach creates. 

What is a 'Pure' Drug?

‘Drug purity’ may sound redundant with drug type, as sometimes a drug gets a new name based on how it is mixed with other substances. While this is often the case for pharmaceuticals that are developed with precision in labs and registered under different names, street drugs are a lot more messy, which is where purity tests come in. These tests work in a variety of different ways, but essentially the purpose of each one is to take a sample of drugs seized and return a resulting percentage, with degree of error or variability, representing how much of that substance is the ‘pure’ form of the drug. 

As drugs are rarely ever 100% pure, the law designates a threshold of purity percentage for different drugs in order for the substance to be labeled ‘pure’, or ‘mixed’ when below threshold. These thresholds vary between different types of drugs. For example, federal sentencing guidelines define a substance as being a ‘mixture of methamphetamine’ if it is less than 80% pure, and ‘pure methamphetamine’ if it is at least 80% pure.

How Does Purity Play a Role in Sentencing?

Under federal law for drug trafficking offenses are assigned a mandatory minimum sentence for their combined type, weight, and sometimes purity. Mandatory minimums are the minimum duration a person can be sentenced to imprisonment when convicted of a certain crime, most commonly used for drugs. Federal drug crimes have two sets of mandatory minimums based on drug type, quantity, and weight: 5 year minimum or 10 year minimum. Under the section of the law detailing both minimums, it first lists the types of drugs punished, followed by required weight thresholds for both a mixed substance and a pure substance. Below is an example of what this looks like:

Except as otherwise provided in section 849, 859, 860, or 861 of this title, any person who violates subsection (a) of this section shall be sentenced as follows:
(1)
 (A) In the case of a violation of subsection (a) of this section involving—
   (iv) 100 grams or more of phencyclidine (PCP) or 1 kilogram or more of a mixture or substance containing a detectable amount of phencyclidine (PCP);
. . . .
such person shall be sentenced to a term of imprisonment which may not be less than 10 years . . .

In the case above, PCP (the type of drug) is punished under a 10 year mandatory minimum when found with at least 100g of the pure substance, or 1 kilogram of mixed PCP. This means that for PCP, its pure form is punished more severely as it carries the same mandatory minimum as a mixture of PCP that is 10 times its weight. Some drugs are treated like PCP where pure substances are treated more severely, but some drugs work the other way around, and others do not account for purity much if at all.

We have listed various drugs and their respective 10 year and 5 year mandatory minimum requirements for pure vs. mixed substances in the table below:

Drug Purity Mandatory Minimums

Drug Type10 Year Min - Pure Weight10 Year Min - Pure Weight5 Year Min - Mixed Weight5 Year Min - Mixed WeightWhich is Worse
Heroin1 kg 1 kg 100 g 100 g same
LSD10 g 10 g 1 g 1 gsame
Marijuana1000 kg 1000 kg 100 kg 100 kg same
Cocaine (powder cocaine vs. crack/impure)5 kg 280 g 500 g 28 g mixed (crack cocaine)
Fentanyl400 g 100 g 40 g 10 g mixed
PCP100 g 1 kg 10 g 100 g pure
Methamphetamine50 g 500 g 5 g 50 g pure

Why are Drugs not all Treated the Same Way Regarding Purity?

The prevailing argument in favor of these mandatory minimums and drug purity disparities is that they are evidence-based, both in terms of chemical differences in drugs and the impact they have on users and communities. While scientific evidence did play some role in how these thresholds were determined, there’s a great deal of politics and misconceptions mixed in as well, not to mention how the law lags behind scientific findings and statistics that have changed since mandatory minimum law’s inception in the 1980’s.

Biomedical Evidence

When looking at this from just a biomedical perspective, it is difficult to say whether one form of a drug is a specific magnitude worse than another as the drug weight and purity penalties reflect. For example, pure methamphetamine is punished 10 times as harshly as a mixture, but mixed methamphetamine can sometimes be even more dangerous than pure methamphetamine. In the case of powder and crack cocaine, crack is considered somewhat more dangerous, but not necessarily an order of magnitude of 18 times worse.

Relationships Between Purity and Other Crimes

Biomedical evidence is not the only kind of evidence lawmakers chose to consider when evaluating drug purity issues. They also looked at this issue in terms of the ways these substances are developed and the criminal activity involved in the process. For example, methamphetamine is a drug that can, and often is, created in at home ‘labs’ using easily obtained over the counter medications and household substances. These at home labs tend to be run by meth abusers themselves or small-scale dealers, and they often produce meth that is impure. When pure meth is found, it has been assumed that the people trafficking it are running a tighter operation, possibly within a broader network of illegal gang activity. This is not necessarily the case in reality, as some large-scale dealers push very impure products, while some people who cook methamphetamine at home are able to make a very pure product.

Politics and Systemic Racism

What many opponents of these drug purity minimums believe is that politics, and especially discriminatory politics and systemic racism, are what largely guided these mandatory minimum drug purity weights. The disparity between crack cocaine and powder cocaine has been the most controversial in terms of a clear racial disparity in sentencing resulting from these laws. While the current federal laws reflect a 18:1 weight ratio for powder to crack cocaine, this was the result of the Fair Sentencing Act of 2010, which congress passed to change the prior 100:1 weight ratio. This was changed because crack cocaine is not very different from powder cocaine in terms of potential harm, but was more commonly circulating working class black communities while cocaine was more commonly distributed in more affluent white communities. Looking back at methamphetamine, it has been argued that the impure kind is punished less severely because it has been stereotyped as a drug created by poor rural white Americans, whereas pure methamphetamine is created by mostly Latin American or Black gangs.

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