Alistair Monroe is living above a recently shut-down indoor cannabis factory-farm in Oakland. He got there long before the pot growers: Monroe has called the historic Cannery building home for most of his life. The building is also home to other members of a live-work artists’ collective that Monroe’s late father, Black abstract expressionist painter and elder community activist Arthur Monroe, formed in 1975. The younger Monroe always felt a deep sense of purpose about living—and watching his father paint giant canvasses—in this creative crucible, which is located in a neighborhood known as Melrose, one of the city’s poorest and home to a population that is 87 percent nonwhite.
Today, this 10-mile swath of Oakland is called the Green Zone because it’s where more than 200 industrial cannabis cultivators are located. Between 2020 and 2022, 13 growers and five other cannabis businesses moved into the ground floor of the Cannery building, as well as into a neighboring building known as the Tinnery. In summer 2020, the operators overloaded the power grid and soon began running massive unpermitted generators at both buildings, enabling them to radically expand cultivation to encompass a 5-acre canopy of cannabis plants, an area about the same size as the neighboring Amazon warehouse.
According to my analysis, the generators burned up to 12,000 gallons of toxic diesel fuel per day—enough to power 9,000 homes. The resulting carbon emissions were four times greater than they would have been if the producers had used the local utility’s far cleaner power. Most or all cultivators defied orders to stop their unauthorized use of the generators.
About three years before the arrival of the generators, the operators attempted to remove the tenants, whose subsequent appeal led to a new ordinance prohibiting evictions by cannabis growers throughout the Green Zone. Adding insult to injury, the operators subsequently attempted to exploit an eviction loophole, which the city promptly closed. Despite these hard-won protections, the 32 people originally living above the Cannery’s grow area dwindled to 10 stalwart souls as conditions deteriorated.
These weren’t the only infractions. Building and safety codes were repeatedly violated, and most of the growers in these buildings failed to obtain mandatory cultivation licenses from the state. Use of the generators also ran afoul of the city’s sustainability regulations, and a federal court sided with residents and the Environmental Democracy Project in claiming violations of the Clean Air Act. Only after there was sustained protest by tenants and local environmental equity organizations did regulators shut down the generators in the fall of 2022—two years after they had been powered up.
When I asked Monroe about his experience living near the generators, he recalled the nuisances of tanker trucks offloading fuel for up to six hours every day, generator noise, and cannabis odors wafting through his floorboards. “The poor air quality, continuous eyes burning from constant dust particles and smoke soot, and the coughing haunt[ed] us daily,” he said in a recent press release from the Center for Environmental Health. The neighborhood already had the city’s worst environmental conditions, topping out at a rating of 100 out of 100 on the hazard scale.
The Green Zone fiasco illustrates how the decriminalization of cannabis in the name of social equity can melt into an environmental justice nightmare if not properly managed.
Regulators have learned a lot from the incident. In early 2023, the California Department of Cannabis Control issued statewide compliance advisories about diesel generators. Greg Minor, deputy director of Oakland’s Economic and Workforce Development Department, said in an email that after the diesel generators at the Cannery and Tinnery buildings were shut down, “City inspectors visited all known Oakland cultivation sites and successfully shut down roughly ten additional sites.” Generators are now explicitly banned in the city’s cannabis operator regulations, Minor said. Similarly, Brian Case, assistant counsel at the Bay Area Air Quality Management District, said in an email that regulators are confident in their ability to quickly halt any future attempts to power cannabis cultivation in East Oakland with diesel generators. They’re committed to sharing best practices with regulators and community groups around the state, he added, because they have “significant concerns about other overburdened communities that are at risk from these operations elsewhere in California.”
These concerns are well-founded, and as I’ve discovered after analyzing the environmental impacts of indoor cannabis cultivation for more than a decade, Oakland’s story is not an isolated incident. As cannabis is decriminalized across America, there are several lessons rule-makers in the rest of the country need to keep in mind.
For starters, heavy reliance on the power grid is a problem. Unlike sustainable “sun growers,” indoor factory farms, which now produce about 60 percent of all U.S. cannabis, disproportionately inflict environmental harms on disadvantaged workers and surrounding communities. It’s an inconvenient truth for an industry plagued by lackluster performance, limited transparency, and greenwashing. Thanks to lighting, heating, air conditioning, and other energy-intensive processes, the carbon footprint of even the “cleaner” grid-tied warehouses involved in cannabis production can be 70 times higher than ordinary warehouses, exacerbating the climate change to which poorer populations are particularly vulnerable. On-site combustion from heating the cavernous buildings, idling diesel trucks, and producing carbon dioxide to boost plant growth releases yet more carbon and also compounds local air pollution.
Warehouses of all types displace people, and the associated trucking creates “diesel death zones,” particularly in predominantly Black and Latino areas. Some developers, meanwhile, are planning to construct large, private fossil-fuel power plants to run mega-grows.
Inside grow facilities, disproportionately nonwhite workers receive pay that mostly hovers around minimum wage while being exposed to a nasty stew of agricultural chemicals, gases, mold, noise, high temperatures and humidity, and harsh lighting brighter than the sun. In one study, nearly three-quarters of workers reported respiratory symptoms (including “probable” work-related asthma), eye and nasal irritation, and allergic reactions. Of particular concern is that workers breathe risky volatile organic compounds, VOCs, which are released from the plants and from dangerous extraction processes—and can reach concentrations hundreds to thousands of times higher than levels outside. Crews also inhale artificial carbon dioxide pumped into work areas at levels which researchers say can impair brain function. One investigation found that 20 people died of asphyxiation from unsafe use of combustion devices.
Outside the buildings, skunky VOC-laden exhaust can be a nuisance and perhaps unhealthful, especially for marginalized communities. The diluted outdoor VOC levels around Denver’s 400 or so licensed indoor cannabis grows, for example, have been measured at four to eight times higher than elsewhere in the already polluted air basin, and Denver’s cultivation sites are typically located in nonwhite and low-income neighborhoods.
Then there’s solid waste, which also has inequitable impacts. One large cultivator produces 326 tons of it per year, 30 times the weight of its product.* These waste streams contain toxic brine from irrigation runoff, fouled artificial growing media, plastics, mercury-containing lights, and mountains of nonmarketable plant residues that can readily form climate-warming methane when landfilled. Additional pollutants leave the indoor grows via wastewater.
It needn’t be this way. Environmental, social, and governance standards being adopted across other industries flag their associated risks to investors, workers, and consumers. Yet, according to rating groups, most cannabis companies have opted out or are conspicuously lagging in ESG fundamentals like transparency, inclusive and fair labor practices, and environmental management.
Regulators have a lot of work to do. They may well be underresourced, but state-level cannabis tax revenues in 2021—$1.3 billion in California, $423 million in Colorado, and $317 million in Illinois—also create an appearance of split incentives for enforcers and government, who may find themselves torn between capturing tantalizing tax revenues and reining in the industry that generates them.
In an ideal world, renewable energy and pollution-control technologies could clean up some of the mess. The expansion of solar energy appears promising at first blush, but thanks to their prodigious energy use, covering a cannabis facility’s roof with solar panels would only provide 5 to 10 percent of the energy it needs. Building solar or wind farms elsewhere is heavily constrained by other environmental, economic, and social factors (and its diversion for cannabis cultivation is arguably frivolous given the pent-up need for it in ordinary buildings such as schools, hospitals, and homes). Filtering the grow room’s exhaust can capture some pollutants, but filters are not consistently effective, and they depend on regular maintenance and elevate energy use. The automation of cannabis jobs replaces and may thus “protect” some human workers, but the efficacy is questionable and the practice runs counter to the industry’s rhetoric about equitable job creation.
One obvious answer is to just farm cannabis outside. Indoor growers insist that their methods are essential in order to avoid the weather risks tolerated by other farmers, achieve uniformly attractive products, boost potency, maximize profits, and enhance security. There are strong counterarguments in each case. But unfortunately, many jurisdictions perversely incentivize this polluting indoor cultivation through tax breaks, license-fee structures, subsidies, or outright prohibitions on outdoor farms, and fall short on consumer education about the environmental footprint of competing cultivation methods.
Lifting federal government bans on interstate transport of cannabis would remove significant barriers to productive outdoor cultivation, allowing more cannabis to be grown in sensible climates. While not every locality is suitable for outdoor cultivation, the industry can afford to pick and choose. Only 0.003 percent of all farmland would be needed to produce the 17,000 tons of cannabis Americans consumed in 2020. As I previously argued in Slate, outdoor cultivation virtually eliminates the carbon footprint of cannabis production—which equated to that of 3 million cars back in 2012 and is no doubt far larger today. The voracious energy appetite of indoor cultivation also makes it particularly vulnerable to climate change impacts such as drought and power outages caused by heat waves.
There is ample evidence that irresponsible outdoor cultivation can also be environmentally destructive, leading some to argue that indoor cultivation is better for the environment because it ostensibly uses less land (thanks to higher yields) and less water (thanks to less evaporation). But in reality, if best practices are followed, the opposite is true. Moreover, the vastly lower startup and operating costs for outdoor farms also lessen the steep inequities that nonwhite owners of businesses face in obtaining financing.
Back in Oakland, the Cannery remains Monroe’s heart and soul. He has created an impressive gallery and preserved his father’s archives while redoubling his commitment to restoring and expanding the Oakland Cannery Collective’s vibrant artist residential community and social mission. Although the cultivation below his home is halted, at least for now, the remaining inhabitants still cannot escape the onslaught of this industry. While the original property owner defaulted on $73 million in debt, new cannabis investors are already waiting in the wings. One of the previous growers now occupies a neighboring warehouse. As Monroe and I walked near it on a recent visit, we were hit by a wall of that unmistakable skunky odor, intermingled with fumes from nearby industrial workshops and freeways. It smelled like a warning.
Future Tense is a partnership of Slate, New America, and Arizona State University that examines emerging technologies, public policy, and society.
Correction, April 27, 2023: This article originally misstated that the cannabis industry produces 150 million tons of solid waste annually nationwide.