By Nelson Harvey

Far more land is available for pot shops in Denver’s low-income, minority areas than in wealthier, whiter parts of the city under current zoning rules, according to a new study by two planning professors at the University of Colorado Denver. And with state rules limiting new entrants to the pot trade set to expire this fall, some researchers worry that the city’s rules could lead to an influx of pot shops in neighborhoods where people are more likely to abuse the drug.

At the same time, research suggests that drug use and abuse may increase in neighborhoods where marijuana dispensaries are located, raising the possibility that decisions about where to site marijuana outlets could have significant implications for public health.

“Regardless of what we do, under current rules, we will locate these businesses disproportionately in poor areas,” said Jeremy Nemeth, the chair of the Department of Planning and Design at CU Denver, who co-authored the study with CU Denver lecturer and mapping specialist Eric Ross. Nemeth noted that although he and Ross looked only at the rules for medical marijuana dispensaries, the same zoning and buffer requirements apply to Denver’s recreational pot shops.

In the study, slated for publication in the winter 2015 edition of the Journal of the American Planning Association, Nemeth and Ross defined Denver’s “socially and economically disadvantaged” (SED) census tracts as those where household income, home values, home ownership, educational achievement and white collar employment were lower than city-wide averages, while rates of poverty and unemployment were higher. In such areas, the researchers found that 46.1 percent of the land was available for marijuana dispensaries, while just 28.9 percent of land in other tracts was available.

In so-called “majority minority” areas where less than 50 percent of the population identifies as white, 34.7 percent of the land was available for dispensaries, compared to 29.3 percent in other neighborhoods.

The results suggest that economic class plays a larger role than race and ethnicity in predicting which neighborhoods will have the most land available for pot shops.

The researchers say their conclusions could be explained by the fact that low-income and minority Denver residents live disproportionately in the commercial and industrial zones where marijuana stores are allowed, while Denver’s wealthiest and whitest neighborhoods are more likely to be in strictly residential zones where such shops are prohibited. The fact that Denver’s pot shops are banned from locating within 1,000 feet of schools, child care centers and drug rehabilitation centers could also play a role in the trend, according to the authors, since there are fewer such establishments in Denver’s poor and minority neighborhoods.

Whether the disparity that Nemeth and Ross identified has already resulted in environmental racism depends on whether dispensaries pose public health threats to the areas around them and whether they’ve already begun flocking to poor, minority neighborhoods. Data on both questions are mixed, but a forthcoming study by researchers at UCLA and the University of Pittsburg may constitute the strongest evidence yet of a link between dispensary density and harms to public health.

Gauging public health impacts

In the study, funded by the National Institute on Drug Abuse and soon to be submitted for publication, researchers tracked the number of people discharged from California hospitals between 2001 and 2011 who had been diagnosed with marijuana abuse or dependency during their stay. They then compared those numbers to the density of marijuana dispensaries in Zip codes across the state, and found that every additional dispensary per square mile corresponded with a 6.2 percent increase in the number of marijuana abuse or dependency diagnoses.

Zip codes with larger minority populations, higher unemployment rates, lower household incomes, lower population densities and a higher concentration of retail stores all had more marijuana abuse and dependency diagnoses, while Zip codes with more college graduates had fewer.

Across California, the researchers found that diagnoses of marijuana abuse and dependency grew from just over 17,000 in 2001 to nearly 57,000 in 2011. Californians legalized medical marijuana in 1999, but the researchers couldn’t say whether the rise in abuse was linked to the proliferation of dispensaries, since state officials only recently began tracking dispensary openings, closings and locations. The research team could only obtain dispensary density data from a single year, 2011, by assembling it from online pot shop databases. Without data on how and where dispensaries had multiplied over time, researchers said, they couldn’t establish a definitive causal link between dispensary density and marijuana abuse.

“The positive correlation doesn’t guarantee a causal link,” wrote Rosalie Pacula, co-director of the Drug Policy Research Center at the Rand Corp., in an email. Pacula is an expert on the effects of marijuana legalization, but was not affiliated with the study. “It is possible that dispensaries (especially in California) emerged in local areas that generally had more positive views/attitudes about use,” she said, “… in which case dispensary outlets are not the cause of the higher use/hospitalizations but the result of areas that are more lenient about use.”

Christina Mair, a professor at the University of Pittsburgh and the lead researcher behind the study, also acknowledged the possibility that California’s dispensaries could have located disproportionately in poor, minority neighborhoods, where previous research has shown that residents are more likely to abuse marijuana, alcohol and other drugs.

“Maybe if we had gone in and looked earlier when there were no dispensaries in California, we would have found that these dispensaries just end up going into more disadvantaged areas,” Mair said.

Yet in measuring diagnoses of marijuana abuse and dependency, Mair and her colleagues controlled for demographics like race, income, age and employment status, and none of these fully explained the increase in marijuana abuse over time that researchers observed.

“I do think that there’s an independent effect of dispensary density [on abuse],” she said.

Measuring the situation on the ground

If there’s a connection between the density of pot shops in a neighborhood and rates of pot abuse there, it adds considerable urgency to the question of whether Denver’s dispensaries are already gravitating toward poor and minority neighborhoods, and what could be done to distribute them more evenly across the city. For now, those remain complicated questions to answer.

One study, published earlier this year in the peer-reviewed journal Urban Geography and co-authored by five researchers including former CU Denver Professor Paul Stretesky (now at Northumbria University in the United Kingdom), found little evidence of pot shops flocking to poor neighborhoods, at least between the years 2000 and 2010. The study concluded that that although Denver neighborhoods that hosted marijuana dispensaries during that time had higher Hispanic populations and higher poverty rates than average, those factors didn’t predict the location of dispensaries once other demographic factors were taken into account.

Yet interpreting the available data another way could yield less rosy conclusions: When Nemeth and Ross analyzed the density of all marijuana businesses (including medical and recreational shops, edible product manufacturers and grow operations) across Denver census tracts in early July of 2014, they did find that the businesses were more densely packed into poor and minority tracts than other areas of the city.

Regardless of how Denver’s pot businesses are distributed, though, observers of the industry point out that it’s hard to say whether zoning rules played a large role in their location decisions, and whether those rules could push them into poor and minority areas in the future. That’s because most of the city’s pot shops opened during the so-called “green rush” of the late 2000s, before the city’s medical marijuana zoning rules and other regulations took effect in 2010.

Jonathan Salfeld, who opened the dispensary Local Product of Colorado in the Civic Center neighborhood in 2009 and has since begun to sell recreational pot as well, said he primarily chose his location to gain good access to his customer base, and that he wasn’t limited by zoning or buffer restrictions.

“Back then, [shop owners] wanted to be in heavily populated areas, commercial areas or even those very small commercial areas within residential areas so that people from the neighborhood could come to their dispensaries,” said Salfeld. “Having off-street parking was also huge.”

Even for dispensary owners who opened their shops after 2010 and had to comply with the new zoning laws, zoning was just one consideration among many in choosing where to do business.

“We opened [this location] in 2013, and zoning was obviously a factor,” said Brett Ahroon, who manages the Starbuds medical and recreational marijuana dispensary in the SED neighborhood of Elyria Swansea just off Interstate 70. “But the main draw for us was customer access, being close to the junction of Colorado’s two major highways.

With hundreds of dispensaries and recreational shops already open in Denver, shop owners do say that finding space for new ventures is getting harder by the day, and much of the remaining land that’s properly zoned may be in poorer neighborhoods.

“I’ve looked at the map a million times to try to figure out where I could start a new one, and it’s almost impossible except in an industrial neighborhood,” Salfeld said.

This fall, state rules will allow entrepreneurs who weren’t previously in the medical marijuana trade to open new recreational marijuana businesses for the first time, which could prompt a flood of new store openings in Denver. Yet partly because of the tight zoning laws and the fact that so much prime real estate is already taken, Salfeld isn’t sure that another green rush is coming.

“Even in the heavy industrial areas, eight out of 10 times it’s impossible [to find space for a store], because people have already done it,” he said.

Responding amid uncertainty

With so many unsettled questions about the distribution of dispensaries and their impact on public health, researchers say they’re eager to keep gathering data on the budding industry that can be used to craft wiser zoning policies.

Since California is now tracking the number and location of dispensaries in the state over time, Mair and her team hope to shed more light in future studies on whether increasing the number of dispensaries in a given neighborhood could also drive up rates of pot abuse there. And Nemeth and Ross say they’ll keep interviewing dispensary owners in Denver to tease out how much zoning rules drive their location decisions.

In the meantime, even if the evidence linking dispensaries to health harms remains ambiguous, a significant number of people don’t want dispensaries near their homes. According to a survey conducted by the Pew Research Center in February 2014, about 43 percent of respondents said they would be bothered if a store selling marijuana opened in their neighborhood.

“We don’t really care if they’re bad, people don’t want them,” said Nemeth. “So is it right to be zoning for them in these poor neighborhoods?”