ROSENBERG, Texas -

An unassuming metal warehouse in Rosenberg became a focal point in a nationwide crackdown on so-called "designer" drugs.

More than a dozen agents from the Drug Enforcement Administration's Houston Division raided the warehouse Wednesday, uncovering hundreds of thousands of packets of synthetic marijuana, cocaine and methamphetamine. Agents also discovered a fully operational lab set up to manufacture and package the drugs under names like "Kush," "Mystic" and "Bath Salts."

"It's killing people, the violence associated with this is out of control," said Javier Pena, special agent-in-charge of the DEA's Houston Division. "We need to take this off the streets."

Pena said the raid was one of 10 in the Houston area targeting an organization manufacturing and selling synthetic drugs at smoke shops and convenience stores. The raid in Rosenberg netted 250,000 packets of synthetic drugs ready for distribution. Pena said these packets had a street value of between $4 million and $5 million.

Agents said they also seized thousands of pounds of chemicals and plant materials. Pena said manufacturers used ground up alfalfa and barley to mimic marijuana. Agents also seized $800,000 in cash, eight guns and 11 vehicles.

"Our message is we're going to go after them, we're not going to rest," said Pena.

According to numbers compiled by the State Department of Health, Harris County is the No. 1 spot in Texas when it comes to synthetic drug poisonings.

"It's very dangerous," said Pena. "We've seen the deaths, we've seen the overdoses off this stuff."

The Houston area raids were part of a nationwide effort by the DEA dubbed Operation Log Jam. Agents fanned out in dozens of cities across the United States seizing synthetic drugs and arresting both retailers and manufacturers. Although no one has been arrested yet as a result of the Rosenberg raid, Pena said "arrests will definitely be forthcoming."

These synthetic drugs have been linked to several outbursts of extreme violence in several US cities. Texas passed a law banning these substances last year and this year a federal ban went into effect.