The chemicals were allegedly sent from China and were meant to go to "clandestine labs" under a drug cartel in Mexico. Officials say there were enough chemicals to make over half-a-billion dollars worth of methamphetamine. Federal officials say a seizure at the Port of Houston marked the greatest bust in U.S. history regarding chemicals used to make methamphetamine. Port of Houston drug bustWhat we know:According to the Department of Justice (DOJ), Homeland Security agents seized over 300,000 kilograms of chemicals that are used to make methamphetamine. It's believed the chemicals were shipped out of China with the intention of going to "clandestine labs" operated by the Sinaloa Drug Cartel in Mexico.