Methamphetamine makers are importing raw powdered meth from Mexico, and refining it at “conversion labs” into the crystal form of the drug, The Wall Street Journal reports. In the past, the drug was produced in small U.S. labs, or shipped in its finished form from Mexico.

Drug groups smuggle large amounts of meth powder or liquid, often disguised as antifreeze or other products.

According to law enforcement officials and academic experts in drug trafficking, Mexican drug groups are adapting to changing markets and legal strategies. Like other businesses, drug traffickers have found it is more efficient to do final processing of their product close to their customers, instead of importing finished products, according to John Donnelly, the head of the U.S. Drug Enforcement Administration’s office in Fresno, California. “Anything that any good businessman does, these guys will do,” he noted.

Conversion labs have been found in California, Georgia and Texas in the past two years. The number of conversion lab busts is growing, as is the size of meth seizures. “We never saw those kinds of seizures before,” Erasmo Carrizosa, the head of anti-meth strategy for the California Department of Justice, told the newspaper. “Before, if you popped a guy for five pounds, it was a lot of meth.”