It’s not news anymore that heroin use in America has risen sharply in the past few years. Even with the increase in demand, though, the illegal opioid is cheaper than cigarettes in some states.

According to the Washington Post, a bag of heroin is as cheap as $5 in Baltimore. By comparison, a pack of cigarettes costs a steep $7.75 in the state of Maryland. A single dose of heroin is less expensive than 20 smokes.

In some states, like Pennsylvania, a bag of heroin can run you about $8, while a pack of smokes is closer to $6. (Of course, the comparison between a single dose of heroin and an entire pack of cigarettes might not be fair, in which case the legal substance is much cheaper).

But, why is heroin—an illegal substance that is in demand—so inexpensive?

With cigarettes, high cost is a function of state taxes levied on the tobacco product. But the low cost of heroin is more of a mystery. According to DEA special agent Joseph Moses, who spoke to the Washington Post, the price of heroin in the U.S. market is largely determined by Mexican drug traffickers, which have expanded their influence as they’ve increased the supply of heroin in the last few years. Moses says this has been a concerted effort in response to the rising prices of opiate pills, such as Oxycontin, on the street.

So, the Mexican drug trafficking organizations’ push to increase supply of the substance on U.S. streets has ensured that there is plenty of it, which has kept the price down despite increasing demand.

H/T Washington Post