An ultra-potent form of heroin that sells for as little as $10 per bag has been making its way across the border from Mexico, the Associated Press reported May 24.

Improvements in poppy refinement by Mexican dealers have driven purity up and prices down. Heroin imported from Asia and the Middle East in the 1970s was around 5-percent pure; now federal agents report seizing drugs at purity levels of between 50 and 80 percent.

The potent heroin can kill unwary users almost instantly if they are accustomed to using weaker versions.

Independent smugglers are driving the new trade from Mexico. While the major cartels focus on marijuana and cocaine, smaller traffickers pay for access to the big cartels’ smuggling routes.

According to the DEA, heroin seizures along the border quadrupled from 2008 to 2009. According to the AP’s research, heroin deaths in the U.S. rose 20.3 percent between 2006 and 2008.

“We’re seeing [heroin] sometimes 80-percent pure,” said Oregon state medical examiner Karen Gunson. “If you’re using it every day, your chances grow and grow that it’s going to kill you.”