Texas politicians thought they were clear: the bill they overwhelmingly passed allowing the growth and sale of hemp had nothing to do with legalising cannabis.

“This is no slippery slope towards marijuana,” Charles Perry, a Republican state senator who sponsored the bill, said in May, according to The Dallas Morning News.

But since Greg Abbott signed the measure into law in June, county prosecutors around Texas have been dropping some marijuana possession charges and declining to file new ones, saying they do not have the time or the laboratory equipment needed to distinguish between legal hemp and illegal marijuana.

Collectively, the prosecutors’ jurisdictions cover more than 9 million people — about a third of Texas’ population — including in Houston, Austin and San Antonio.

The accidental leniency represents one of the unintended consequences states may face as they race to cash in on the popularity of products made with or from hemp.

Where is cannabis legal in the US? Show all 11 1 /11 Where is cannabis legal in the US? Where is cannabis legal in the US? Alaska Recreational cannabis use was made legal in Alaska in 2014 Getty Where is cannabis legal in the US? Washington Washington was among the first states to legalise cannabis in 2012 Getty Where is cannabis legal in the US? Michigan Recreational cannabis use was made legal in Michigan in 2018 Getty Where is cannabis legal in the US? Massachusetts Recreational cannabis use was made legal in Massachusetts in 2016 Getty Where is cannabis legal in the US? Colorado Colorado was among the first states to legalise cannabis in 2012 Getty Where is cannabis legal in the US? Vermont Since January 2018 it has been legal to posses up to one ounce and two cannabis plants in Vermont. Commercial sales are not legal Getty Where is cannabis legal in the US? California Recreational cannabis use was made legal in California in 2018 Getty Where is cannabis legal in the US? Illinois Recreational cannabis use was made legal in Illinois in 2019 Getty Images Where is cannabis legal in the US? Oregon It was made legal in Oregon to possess up to one ounce of cannabis in 2014 Getty Where is cannabis legal in the US? Maine Recreational cannabis use was made legal in Maine in 2016 Getty Where is cannabis legal in the US? Nevada Recreational cannabis use was made legal in Nevada in 2016 Getty

Interest has surged in oils, gummies and other goods infused with CBD, or cannabidiol, which is processed from cannabis plants but does not produce a psychoactive effect.

The police and prosecutors in Florida are facing the same problem as their Texan colleagues after the Sunshine State legalised hemp in July.

“This is not just Texas,” said Peter Stout, president of the Houston Forensic Science Centre, which runs tests for the Houston Police Department and other agencies.

“Everybody is struggling with this.”

In Texas, prosecutors have already dropped scores of possession cases, and they’re not just throwing out misdemeanours.

The Travis County district attorney, Margaret Moore, announced this month that she was dismissing 32 felony possession and delivery of marijuana cases because of the law.

Ms Abbott and other state officials, including the attorney general, pushed back on Thursday, saying prosecutors should not be dropping cases because of the new legislation, known as H.B. 1325.

“Marijuana has not been decriminalised in Texas, and these actions demonstrate a misunderstanding of how H.B. 1325 works,” the officials, all Republicans, wrote in a letter to prosecutors.

Kim Ogg, the Harris County district attorney and a Democrat, shot back by saying that laboratory confirmation “has long been required” to prove someone’s guilt.

Before the legislation went into effect, laboratories had to identify hairs on marijuana flowers and test for the presence of cannabinoids, a process that required just a few minutes and a test strip that turned purple when it was positive.

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Because the new law distinguishes between hemp and illicit marijuana, prosecutors say labs would now be required to determine the concentration of THC in the seized substance.

Mr Stout said he has been able to identify only two labs in the country that can make the fine distinction necessary and that are accredited in Texas. Both of them are private.

Prosecutors would need to pay the labs to run the tests — sometimes hundreds of dollars for each sample — and to testify about the results at trial.

Sending all of the state’s suspected marijuana to a small number of labs would likely overwhelm them, prosecutors have said, and would result in severe backlogs.

Still, many prosecutors agree with the governor and are continuing to charge and prosecute marijuana cases as usual.

The district attorney in El Paso, Jaime Esparza, a Democrat, said this month that the law “will not have an effect on the prosecution of marijuana cases in El Paso” and a spokeswoman confirmed that he had not thrown out any cases because of the law.

The sudden dismissals in other districts have been a welcome surprise for those who had been facing charges.

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Brandon Ball, a lawyer, said one of his clients in Fort Bend County had been distraught about the possession charge she faced until it was unexpectedly dismissed.

She kept thanking him, but it wasn’t her lawyer who beat the case.

“I was trying to explain, it wasn’t me, it was this law,” Mr Ball said, referring to the hemp legislation.

Mr Ball, now an assistant public defender in Harris County, explained that test results are vital for prosecutors trying to prove that someone had an illegal substance.

“The law is constantly changing on what makes something illegal, based on its chemical makeup,” Mr Ball said.

“It’s important that if someone is charged with something, the test matches what they’re charged with.”