PIERRE, S.D.(KELO)- Just about the time they get one drug under control, a new one comes on the black market.

That’s the frustrating position for law enforcement trying to get ahead of the deadly fentanyl market.

Attorney General Marty Jackley says drug cartels often change the chemistry of their drugs to stay ahead of the law.

He wants Congress to change that.

Jackley is among 23 Attorneys General asking the U-S Senate to pass the HALT Fentanyl Act.

It’s a far-reaching proposal already approved by the House that permanently regulates all forms of fentanyl.

Prosecutors are looking for some help from Washington in the war against fentanyl.

Jackley is joining colleagues from across the country.  They’re asking the U.S. Senate to pass the “HALT Fentanyl Act”.

Jackley says the measure would give prosecutors the tools they need to go after drugs across the country.

He hopes the Senate takes advantage of a window of opportunity.Jackley says it would put prosecutors a step ahead of the drug cartels.

He says Congress missed a similar opportunity recently.

He feels like he’s in a war without many weapons to use.

Drug cartels change the chemistry of fentanyl regularly, to avoid laws that control the drug.

Jackley has a simple message for Washington.

The U.S. House has already passed a bill recommended by by Jackley and other Attorneys General.

He’s hoping to get it through the Senate soon.