Measuring drug seizures at the southern border: How Reuters analyzed the data

By Jackie Botts

MEXICO CITY (Reuters) - Through a Freedom of Information Act (FOIA) request, Reuters obtained and analyzed a dataset of drug seizures by U.S. Customs and Border Protection (CBP) agents at ports of entry along the U.S.-Mexican border from January 1, 2012 through December 31, 2022.

The seizures data analyzed by Reuters reflects changes in trafficking patterns and authorities' sharper focus on fentanyl, experts and officials said.

The data encompasses seizures at southern border ports of entry, where most illicit drugs consumed in the United States, including fentanyl, are currently smuggled.

That said, fentanyl has also been documented being trafficked from Mexico to the United States through international mail, in airplane luggage, concealed in maritime shipping containers, through underground tunnels and in drones – methods not captured in the data.

Via FOIA, Reuters also requested seizures of drugs by Border Patrol agents along the vast stretches of the southern border between ports of entry. CBP did not respond to the request so drug seizures between ports of entry are not included in Reuters' analysis.

Border Patrol seizures represent a minority – between 13% and 19% – of the total weight of seizures at the border for cocaine, fentanyl, heroin and methamphetamine. For marijuana, on the other hand, nearly 70% of the total weight of seizures at the southern border take place between ports of entry in the last several years, according to CBP data available online. For the five principal drugs analyzed by Reuters, including marijuana, the online data show that trends in seizures at ports of entry largely track those of seizures between them.

The dataset originally included 107,353 rows, which describe drug seizure events as well as samples of seized drugs that are sent to U.S. government laboratories for analysis. To remove such samples, Reuters omitted from its analysis drug seizures with no weight or that mentioned within the seizure description the law enforcement agencies that run the sampling labs.

The Reuters analysis focuses on the five most commonly seized drugs - marijuana, methamphetamine, cocaine, heroin, and fentanyl - which comprise 84% of all seizures at southern border ports of entry over the past decade.

Because the focus of Reuters' reporting was large-scale drug smuggling, Reuters omitted seizures of small amounts likely destined for personal use. With the guidance of multiple drug trafficking researchers, Reuters used the following cutoffs: one kilo for marijuana, 100 grams for cocaine, 100 grams for methamphetamine, 20 grams for heroin and 20 grams for fentanyl.

To estimate opioid doses seized at the U.S.-Mexico border, Reuters assumed that heroin seizures at the border are 60% pure, heroin sold to consumers is 40% pure, border seizures of fentanyl powder and fentanyl tablets are 8% pure and 1.25% pure respectively, and fentanyl tablets typically contain 1.5 mg of pure fentanyl. These purity assumptions match those used by the Commission on Combating Synthetic Opioid Trafficking, based on drug purity averages reported by CBP and the Drug Enforcement Agency (DEA).

A recent DEA study noted that fentanyl purity has risen over time and reported higher average purity of fentanyl pills and powder - 14.4% purity in powder and an average of 2.2 mg of pure fentanyl in tablets - in a 2021 sample of over 1,000 fentanyl seizures within the United States. Given that fentanyl purity has changed over time, Reuters decided to use the more conservative purity assumptions used by the Commission for its dosage calculations.

About 10% of fentanyl seizures mentioned words like "powder" or "brick" while about a third included the words "pill" or "tablet." For fentanyl seizure events that did not mention such words, Reuters assumed the fentanyl was 1.25% pure. Hence, the analysis almost certainly undercounts fentanyl doses.

Reuters assumed that a typical dose of pure fentanyl is 1.5 mg – the amount regularly found in tablets – and that a single dose of heroin is 40 mg – given that single doses of heroin are typically sold on the streets in bags that weigh 100 mg at around 40% purity. Thus, Reuters estimated that one kilo of fentanyl tablets would contain around 8,300 doses, one kilo of fentanyl powder contains 53,300 doses, and one kilo of heroin contains 15,000 doses.

Seizures of all drug types increased in 2020 compared to 2019, as well as an overall spike in low-weight seizures and seizures on pedestrians.

Drug trafficking experts consulted by Reuters attributed the increases, in part, to CBP being able to inspect more border-crossers at the start of the pandemic due to decreased traffic across ports of entry. Because drug seizures have largely recovered to prior patterns, Reuters did not focus on these pandemic-era disruptions in its analysis.

Reuters' analysis also shows methamphetamine seizures falling over the past 18 months to 2019 levels, bucking a trend of rapid upward growth in the years prior.

This sudden drop puzzled experts consulted by Reuters. While several posited that the decline could be explained by border authorities prioritizing detection of fentanyl at the expense of catching less deadly meth, others suggested that organized crime groups may be trafficking less meth into the United States due to falling retail prices or because the market of potential users may be saturated.

(Reporting by Jackie Botts; Editing by Janet Roberts and Frank Jack Daniel)