Marijuana is no longer a budding industry in Colorado. It has blossomed into a $1 billion industry for the state. While it has received praise for helping to build the state's economy, the marijuana industry still remains under scrutiny when it comes to travel and hospitality.

"It's remarkable that less than seven years ago, all of that money was being spent in the underground market," said Mason Tvert, the Marijuana Policy Project's communications director. "Clearly, there's a large demand for marijuana, and we're now seeing that demand being met by legitimate businesses that are answering to authorities instead of criminals who answer to nobody."

In 2014 — the inauguration year for legal sales of pot it was a $699 million industry. As more businesses, cities and towns became more open and involved in the green leaf industry, the number of sales grew to $996 million in 2015. Taxes and license fees also grew from $76 million in 2014 to $135 million in 2015.

While the economy sees the positives of legal marijuana; one industry in particular travel remains skeptical. But recent data suggest some visitors are influenced to legally use weed for recreational purposes while on vacation.

In a survey conducted by the Colorado Tourism Office (CTO), approximately 49 percent of visitors who traveled to Colorado during the summer were influenced to visit the state because of legal marijuana usage.

"I think it is rearing its head as a significant travel and tourism amenity for visitors coming to Colorado," Al White, retired boss of the CTO, told The Denver Post.

Despite the high percentage of visitors contributing their visit to weed, the state stands firm on its stance not to promote the legal substance. The state instead contributes its growth to the ongoing tourism marketing campaign.

A recent study found the CTO's marketing campaign "Come to Life" generated 2.1 million trips and $2.6 billion in traveler spending from April to August 2015.

"I believe one of the ways we've found success in this state is by not focusing just on places to go and things to do," CTO Director Cathy Ritter told the Denver Business Journal. "We're explaining to people how their life will change by visiting Colorado ... We will continue building on this campaign because it's resounding with people."

The research firm who conducted the survey, Strategic Marketing and Research, did ask whether the legalization of marijuana influenced participants' visits to the state. Eight percent of people visited a marijuana dispensary while visiting, 85 percent of that group listed marijuana as a Top 3 activity they did while in Colorado. That means about 6.8 percent of Colorado's visitors were heavily influenced to visit the state because of marijuana.

"The information that we do have ... is that the legalization of marijuana is actually attracting only a very small segment of traveler," Ritter said. "But for the large majority of travelers, it's a ho-hum issue."

However, tourism businesses such as 420 Tours and Bud & Breakfast are seeing the successes of the pot tourism business in the state. My420Tours hosts about 120 to 200 visitors per week and is looking to expand the business in other pot-tourism-friendly states such as Oregon.

"The state of Colorado has had an amazing opportunity to embrace this industry," he said. "It a complete advantage for Colorado to become the Napa Valley and Sonoma County of cannabis."

While those in the industry ride high on the number of visitors influenced to visit the state because of marijuana, another aspect of the industry in the state is also making waves the number of ER visits by out-of-state visitors due to pot-related incidents, which grew 109 percent from 78 per 10,000 ER visits in 2012 to 163 per 10,000 visits in 2014.

"The interpretation is that emergency room visits possibly related to cannabis use are increasing in both Colorado and out-of-state residents, but the rate is increasing more dramatically among out-of-state visitors," said lead investigator Dr. Howard Kim, a postdoctoral fellow in emergency medicine at Northwestern University's Feinberg School of Medicine and an emergency medicine physician at Northwestern Medicine.

"Our hypothesis is that out-of-state visitors weren't as aware of the potential side effects of marijuana use."

While the study did not differentiate whether ER patients smoked marijuana or ingested edible pot products, Kim believes that inexperienced users are unaware of the delayed effect of the edibles.

"Frequently, inexperienced users will eat a pot brownie, not feel any effects and think it isn't working and so they eat another pot brownie. So when the effect finally kicks in two or three hours later, they now have had multiple marijuana products," Kim said.

With the increase in numbers, people are questioning how businesses can prevent visitors from getting ill while trying while trying to indulge in the drug. The Marijuana Policy Project did create a campaign aiming to educate travelers on responsible consumption and wanted to post those ads at Denver airports, but that idea was declined.

"There's no doubt education is effective at preventing overconsumption," Tvert said. "If the state's efforts and those by organizations and businesses are resulting in more informed consumers locally, the state should look into ways of getting that information to tourists."