Ben Siller looked ridiculous on a recent afternoon, standing on a downtown Denver street corner with a giant device clamped to his face sniffing the air for odorous evidence of marijuana.

“What are you doing?” asked Jimmy Smith, owner of Higher Expectations dispensary south of Mississippi Avenue near the South Platte River.

In the dawning age of legal marijuana in Denver, the city is getting more and more complaints about the unmistakable odor wafting through the streets — a skunky, herbal scent that has prompted dozens of calls to the city’s hotline.

That’s when Siller with his Nasal Ranger device jumps into action.

An investigator with the Denver Department of Environmental Health, Siller for 26 years has been looking into odor complaints. They can range from smoke from a kitchen to industrial odors.

Siller will bring his device to the area and sniff the air, determining whether the odor violates the city odor law. Rarely does that happen.

“It has to be a very strong odor,” Siller said.

The pungent odor of marijuana plants or even second-hand pot smoke won’t violate the odor law, which is determined by volume. A violation occurs after the odor exceeds the 7-1 ratio — when one volume of odor is detectable with seven or more volumes of nonodorous air.

The Nasal Ranger — the conelike contraption that Siller attaches to his nose — dials in the strength of the odor. Almost never does the smell surpass the 7-to-1 dilution threshold.

It hasn’t happened since 1994. Odors would have to be pretty strong, an industrial-level aroma, like what would come from an ill-managed rendering plant.

Marijuana smoking or grow facilities won’t reach that level, Siller said. Most grow facilities have ventilation systems and filters to prevent odors from escaping, even when marijuana cultivation is at its stinkiest during the harvest times, said Smith, owner of Higher Expectations.

Siller also advises warehouses to be good neighbors and try to reduce the odors as best they can, even though they are not breaking the law.

The city also may issue citations when five or more residents call in an odor complaint within a 12-hour period. That also rarely happens but is more frequent.

New odor in town



Neighbors in the Washington Park neighborhood last year called in successive complaints about a wood-burning pizza restaurant, which was cited and later put in a system to diffuse the smoke.

Also, neighbors in the River North neighborhood have regularly complained about Kasel Industries, which makes pig-ear dog treats. The city gave Kasel a $500 citation for nuisance odors, and the company turned around and sued the city. The cases were later dropped, Siller said.

As far as marijuana, complaints began coming in a few years ago from people saying they were smelling a new odor in the city, mostly around industrial areas.

“I had an old guy call, complaining about this unusual odor whenever he drove past Mississippi and Santa Fe,” Siller said. “I knew right away what it was, and told him that it was marijuana. His reaction was, ‘What?’ “

From January to September, the city received 85 odor complaints, 11 related to marijuana. Last year, there were 288 odor complaints and 16 were marijuana-related.

The Denver City Council last month presented a list of proposed rules about marijuana possession and consumption that would have prohibited even the smell of marijuana smoke coming from private properties.

“I thought, ‘Uh-oh, we are going to start getting calls,’ ” Siller said.

That rule has been scaled back, and the council meets again on the matter Tuesday.

Council President Mary Beth Susman said the city must evaluate its odor laws. Now, public consumption of marijuana is illegal, but no recourse exists for people affected by the smoke or who are offended by the odors.

“Odor can be subjective,” Susman said. “It’s hard to legislate odor. The strength that is required to register on the Nasal Ranger is something we need to look at. I also wonder if people will get used to the smell and the dislike of it now may change over time.”

Councilman Charlie Brown, who chairs the committee looking into marijuana issues, said he wouldn’t like for his privacy to be violated by marijuana smoke.

“If I was hosting a birthday party for 7-year-olds in my backyard and the neighbors’ marijuana smoke was drifting over the fence, I would be concerned,” he said. “The best way to prevent that is to communicate with your neighbor. The truth is creating an ordinance to prevent it is very difficult, but the council is looking at a variety of options.”

Jeremy P. Meyer: 303-954-1367, jpmeyer@denverpost.com or twitter.com/jpmeyerdpost