When they were first writing Breaking Bad, creators reached out to the Drug Enforcement Agency because of the very drug-oriented content of their show. The writers reached out to the agency and asked for their input. Speaking to High Times, Bryan Cranston commented on the agencies involvement saying, “We informed them—with all due respect and consideration—that we’re doing this show, and ‘Would you like to be a part of it in a consultancy in order to make sure that we get it right?’”.
Apparently, the DEA was interested in the deal and Cranston continued, “They had the choice to say, ‘We don’t want anything to do with it.’ But they saw that it might be in their best interest to make sure that we do it correctly. So DEA chemists came onboard as consultants and taught Aaron Paul and me how to make crystal meth.”