More than 2 million Americans are addicted to prescription painkillers. Each day 7,000 people are treated in hospitals for misusing these drugs, and 44 people die from overdosing on them.

CDC

What began as genuine treatment for, say, chronic pain has become a burden for those who get addicted. The most common drugs in this category are opioids and benzodiazepines. When the addicts are no longer eligible to get their prescriptions, they start looking elsewhere. That has created a new generation of drug dealers peddling in legal highs.

These dealers will go to great lengths to acquire these highs for their customers, because there is a lot of money to be made. A pill of methadone, which costs less than 20 cents in a pharmacy, is sold for $20 on the street.

In 2010, for instance, thieves stole $80 million worth of drugs from an Eli Lilly warehouse. Following this, pharma companies began adding security at warehouses and in their delivery trucks. So instead, reports Stat, in the last two years, thieves have started targeting smaller pots, such as vans that deliver supplies to a pharmacy.

These last-mile thefts are difficult to prevent. Most of these courier van drivers work for an independent company, have little training, and don’t carry a weapon. That’s why such thefts are on rise. There were 87 such cases in 2015, up from 72 cases in 2014, according to Pharmaceutical Cargo Security Coalition.

Companies are looking to reduce these thefts. But, as one driver who was robbed at gunpoint for prescription painkillers told Stat, “You really can’t stop this. People who are addicted to these painkillers, they will pay for it.”