MASSACHUSETTS LAWMAKERS OPPOSED to legalizing marijuana brought in an array of law enforcement officials as well as a buffet of kid-enticing pot products to try to scare the state straight before a ballot question to regulate the weed makes it before voters in November.

“This entire Commonwealth has been affected by the opioid addiction crisis,” said state Rep. Harold Naughton, House chair of the Joint Committee on Public Safety and Homeland Security. “People may think it’s unfair to start the conversation about marijuana with reference to opioids, but I don’t think it’s unfair. Marijuana is a gateway drug and to ignore that fact is at our own peril and the peril of our children.”

South Shore state Reps. Josh Cutler and James Cantwell organized the packed meeting in the House members’ lounge as the opening salvo of a bid to scuttle the momentum of proponents seeking to have Massachusetts join Colorado, Oregon, Alaska, and Washington in legalizing recreational use of marijuana.

Proponents have already cleared the initial hurdle by submitting well above the required 64,750 signatures in support of placing the question on the ballot. The Legislature has until May 2 to act on the petition from the Campaign to Regulate Marijuana like Alcohol. If lawmakers don’t act or vote down the measure, supporters must gather nearly 11,000 more signatures to place it on the ballot in November.

Even if the Legislature passes the initiative petition, Gov. Charlie Baker has promised to veto it, making a ballot showdown all but certain. The House recently held a hearing on a separate, but similar, bill from 15 members that would legalize the drug, but it’s unlikely to come up for a vote.

Both lawmakers and law enforcement officials said the biggest danger with legalizing the sale of marijuana is the marketing that they claim is geared toward children, with the use of eye-catching packaging as well as edible marijuana products such as gummy bears, lollipops, and salt water taffy. Some legislators pointed to the parallels with the tobacco industry, which has long been charged with aiming advertising at children.

“It’s amazing how intertwined the tobacco and the marijuana industry are,” said state Rep. Carolyn Dykema of Holliston.

Jim Gerhardt, a Thornton, Colorado, police officer who is vice president of the Colorado Drug Investigators Association and who travels the country to urge states not to follow Colorado’s lead, offered a sobering presentation that runs counter to claims that all is well in Centennial State, which became the first in 2012 to legalize personal possession and use of marijuana.

Gerhardt said passage of the referendum there was the result of a “well-organized campaign” that convinced voters marijuana was as benign as alcohol and tobacco, and that legalizing it would relieve law enforcement from chasing petty users as well as reduce the number of alcohol-related crimes.

“We have seen no evidence of that; all of our alcohol problems have remained exactly as they’ve been,” Gerhardt said. “In surveys about marijuana use, Colorado now has the highest use rate in every age category.”

Gerhardt relayed grisly stories of marijuana-intoxicated individuals committing gruesome suicides or even murders, dismissing claims by proponents that users tend to mellow out. Gerhardt ticked off a laundry list of negative impacts since legalization in his state, from an increase in marijuana-related suspensions and expulsions among school-aged children to a reported rise in veterinarians treating dogs for toxicosis caused by pets either inadvertently ingesting the pot or purposely being fed the drug by their owners.

Gerhardt also said the claim that legal marijuana would stuff state coffers with tax revenues is a myth. He said in the last fiscal year, legal recreation marijuana brought in $52.5 million in taxes while medical marijuana accounted for a little more than $10 million. He said that total is less than 1 percent of total tax revenues brought in by the state, hardly a game-changer. Colorado levies a 30 percent tax on recreational marijuana and a much lower burden on medical marijuana. The ballot question in Massachusetts would cap the tax at 12.5 percent for recreational sale while medical marijuana is tax-exempt.

When asked by a House staffer how to justify the fact that alcohol and tobacco are legal despite health concerns while marijuana isn’t, Gerhardt said it was a matter of public acceptance. “Two wrongs don’t make a right,” he said. “We have a 2,000-year-old culture of embracing alcohol and hundreds of years of a culture of embracing tobacco use.”

Matt Gutwill, a Framingham police detective who has worked with the federal Drug Enforcement Administration, said it’s a myth to think law enforcement was spending time rounding up marijuana users and tossing them in jail. “I don’t ever remember putting someone away for simple possession,” he said.

Gutwill, who has been involved in drug enforcement since the turn of the century, says he also has a personal stake in examining the claims of beneficial uses of marijuana.

“I have two kids with cystic fibrosis,” he said. “I’m always reading the studies on drugs and what works. I would never give my kid a drug that hasn’t been brought to a case study.”

Near the end of the forum, two state senators who made a recent fact-finding trip to Colorado, Linda Dorcena Forry of Dorchester and Vinnie deMacedo of Plymouth, offered their takeaways. DeMacedo said with the changes already taking place in the Bay State that have decriminalized possession of small amounts of marijuana and legalized it for medical purposes, there is plenty of time to see how full legalization works out in the other states.

“People are not going to jail and those who need medical marijuana are getting it,” said the first-term Republican. “Why are we jumping quickly into this?”

(Correction: An earlier version of this story inaccurately stated the tax on medical marijuana in Colorado.)