As “pill mills” close in Florida due to increased law enforcement, the sale of opioids is booming online, according to the Palm Beach Post.

It is against federal law to possess narcotics without a valid prescription, or to sell narcotics online without a prescription, the article notes. But many websites do sell narcotics to people without a prescription, the newspaper found. Some Web pages require only a quick oral or written exam by a doctor, or sell access to other websites that sell drugs without an in-person consultation with a physician.

Some websites are based abroad, although it is difficult to determine where many of the Web pages originate. The newspaper found some of these shadowy websites accept Mastercard and Visa, and some us the U.S. Postal Service to deliver the drugs.

While Google recently agreed to pay $500 million to settle charges that it advertised online Canadian pharmacies that targeted U.S. consumers, and will not accept advertising by so-called rogue pharmacies, the company’s search engine pulls up lists of online pharmacy websites that will sell Vicodin without a prescription.

Facebook and Twitter offer ads for opioids and other drugs. A spokeswoman for Facebook told the newspaper the company removes the ads when they learn about them.