Montgomery County, Texas Sheriff Rand Henderson called fentanyl a "weapon of mass destruction" Tuesday as the lethal drug continues to claim the lives of Americans. 

Henderson said on "Fox & Friends" the open border has facilitated drug cartels and addressed the unaccompanied minors missing from Houston since last year.

"There is no quality control standard. And it is truly a weapon of mass destruction that's killing our population," he said.

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The Texas sheriff said fentanyl is being sent through the "regular cartel route" and is a drug that is unlike anything he has seen in his career.

"I thought I would never see anything worse than methamphetamines, which has been a horrible scourge on our population. But this is taking it to a new level, and it's truly a poison."

Henderson said there are ongoing efforts to reclassify the drug, "in a way that Greg Abbott, is looking to do, is to label this not only as a narcotic but as a poison." 

Such a measure would increase the penalties for distributing the drug in the state, the sheriff explained.

The DEA has already seized brightly-colored fentanyl in 18 states so far this month, a new trend the agency says drug traffickers are capitalizing on to drive young people to the deadly drug. 

"This trend appears to be a new method used by drug cartels to sell highly addictive and potentially deadly fentanyl made to look like candy to children and young people," the DEA said. 

Since last year, there have also been 57 missing unaccompanied minors in Houston. 46 have been reported safe, but there are still 11 unaccounted for.

"We're constantly looking for those that are missing both migrant children and those that have entered into the sex slave trade. So that's a concerted effort between a lot of groups, NGOs, as well as government organizations, to try to locate and return children and young adults safely where they belong."

Fox News' Paul Best contributed to this report