Two major Texas law enforcement groups on Tuesday decried pending legislation to loosen marijuana laws as the beginning of a “slippery slope” into full legalization of the drug.

“The blueprint for the proponents of marijuana legalization is clear and has been effectively used in other states,” Grand Prairie Police Chief Scott Dye said. “This is a calculated and systematic approach by a minority of our population who use marijuana and/or stand to gain from marijuana production.”

Dye and other law enforcement officials representing the Texas Police Chiefs Association and the Sheriffs’ Association of Texas said legalization would bring increased crime, entice a dangerous black market and lead to increased use of other, more addictive drugs.

The groups urged the Texas Legislature not to lower criminal penalties for possession of small amounts of marijuana, which is now punishable by up to six months in jail. The groups also oppose expanding the state’s restrictive medical marijuana program until “validated, peer-reviewed medical research shows a proven medical benefit.”

Their comments came just a day after a bill that would decriminalize possession of an ounce or less of marijuana passed out of a House committee, clearing the measure for a possible vote by the full House.

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House Bill 63 would lower the penalty for the crime from a Class B misdemeanor to a civil offense with a fine of up to $250 and no jail time.

Texas Department of Public Safety data shows that in 2017, more than 66,000 people were arrested for possession of marijuana, making up about 49 percent of all drug possession arrests. The data does not break down the arrests by the amount in possession, nor does it show how many of the arrests included other charges.

Some Texas counties, including Bexar, Harris and Travis, have already taken steps to decriminalize low-level marijuana possession, after the Legislature in 2007 passed a cite-and-release law allowing police to issue offenders citations, rather than arrest them.

Sheriffs and police chiefs from those counties were not present at the press conference Tuesday.

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Heather Fazio, director of Texans for Responsible Marijuana Policy, on Tuesday said she does not believe that lighter penalties for possession mean that the state is moving toward legalization.

“That’s where we’re finding the most common ground,” Fazio said. “Our current penalties are harsh, they’re unreasonable and unpopular … The bottom line is Texans don’t want to continue wasting our valuable criminal justice resources arresting people for the possession of marijuana.”

Fazio said a criminal record for a possession charge can hinder an otherwise law-abiding person’s access to education, employment and housing.

A poll of registered voters last summer found 53 percent favored legalizing marijuana, at least in small amounts. The internet poll of 1,200 voters conducted by the University of Texas and the Texas Tribune had a margin of error of 2.8 percentage points.

Last year, the Republican Party of Texas updated its platform to support decriminalizing possession of small amounts of marijuana, and Gov. Greg Abbott said he is open to reducing criminal penalties in those cases.

HB 63 was among more than 50 related to marijuana filed this session, including one bill that would create a state medical marijuana program and another that would legalize industrial hemp production and research.

Kilgore Police Chief Todd Hunter, president of Texas Police Chiefs Association, said the group generally opposes decriminalization, but it may support making low-level possession a Class C misdemeanor, if it required offenders to enter a diversion program.

“The issue we have with failing to prosecute small amounts of marijuana, we’re not even able to put those folks into a diversion program to give them the opportunity for treatment,” Dye said. “We haven’t been putting those small amounts in jail for years, but we know a lot of those folks need treatment.”

House Bill 63 sponsor Rep. Joe Moody, D-El Paso, who has worked to pass similar bills since 2015, has expressed optimism about its chances this session.

“On many, many levels, the current law is not sound policy,” Moody told the Hearst Newspapers earlier this month. “The punishment doesn’t fit the crime and we need a different way of doing things in Texas.”

According to a 2013 American Civil Liberties Union report, black people are nearly four times more likely than white people to be arrested for marijuana, though both groups use the drug at similar rates.

Presented with that statistic Tuesday, Hunter said he had never heard of the report and didn’t “perceive it as accurate.”