A father turned activist who lost his son to a fentanyl overdose penned a letter to Sen. Cory Booker, D-N.J., urging him to drop his opposition to permanently classifying fentanyl-related substances as a Schedule I controlled substance.

"In response to the deadly impact of fentanyl and the speed with which the cartels develop new analogues, the Drug Enforcement Administration (DEA) issued an emergency scheduling order that classified FRS as schedule I controlled substances," reads a letter from Victims of Illicit Drugs President Jamie Puerta to Booker that was obtained by Fox News Digital. "Congress extended this order six times, during both Republican and Democratic presidential administrations. That is, until you objected."

Puerta, who lost his son Daniel to a fentanyl overdose, took issue with Booker's decision earlier this year to object to extending the DEA's emergency scheduling of fentanyl-related substances, with the senator arguing the class-wide scheduling of fentanyl has been a "failed experiment" while calling for a bipartisan solution to the crisis.

"This was the bipartisan solution," Puerta said. "And you were its sole objector."

CALIFORNIA TEEN CHARGED WITH MURDER FOR PROVIDING FENTANYL TO DRUG OVERDOSE VICTIM

Cory Booke gestures during senate hearing

Sen. Cory Booker, D-N.J. (AP Photo/Alex Brandon)

Booker has long raised concerns over permanently scheduling fentanyl analogues as Schedule I controlled substances, saying in June that a class wide scheduling "may improperly classify FRS that may be harmless, or have a medical use, as Schedule I drugs."

Booker has also argued that Americans could unwittingly end up in legal trouble for trafficking fentanyl-related substances that are non-bioactive, a concern Puerta countered has little evidence of being legitimate.

"To date, every FRS has been found to produce opioid receptor bioacticity – even the single FRS that does not initially present as a mu-opioid receptor stimulator but becomes one with higher doses," Puerta wrote. 

"Instead of presenting scientific evidence, you imagined a defendant who hypothetically distributed pharmacologically ineffective FRS," Puerta continued. "This defendant does not exist. He never will. And for good reason: drug use is driven by the pursuit of a pharmacological effect. Drug dealers do not profit from peddling placebos."

Fentanyl compared to candy

15,000 fentanyl pills seized by law enforcement (Connecticut's U.S. Attorney's Office)

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Fentanyl has become the main driver of the U.S. opioid crisis, with the drug being responsible for nearly 75% of fatal drug overdose deaths last year.

Senators are expected to bring the issue to the floor of the chamber later this week, with a potential bid to pass a scheduling bill by unanimous consent, which would require the support of Booker.

rainbow fentanyl pills

The DEA said rainbow fentanyl can be pills or powder that come in a variety of bright colors, shapes and sizes.  (DEA )

"Unlike your imagined defendant, my son was real," Puerta wrote to book ahead of the potential showdown, adding that "very real children deserve to have their interests placed above your made-up defendant. Please withdraw your objection to FRS scheduling."

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Booker's office did not immediately respond to a Fox News request for comment.