On 8 May, an article from Insight Crime explains that production of fentanyl and methamphetamine requires key ingredients known as precursor chemicals. It says that synthetic drug producers in Mexico have found ways to circumvent regulations to obtain the precursor chemicals, and a sophisticated network of brokers has allowed them to find and buy pre-precursors, less regulated chemicals used at an earlier stage of the production process for methamphetamine and fentanyl. The report from InSight Crime breaks down the different stages of the supply chain for these synthetic drugs. It looks at the chemical companies manufacturing and selling the precursors in China and India, the transnational network of buyers sourcing the precursors, and the chemists and cooks synthesising the drugs in Mexico.
https://insightcrime.org/investigations/chemical-precursors-mexico-synthetic-drug-meth-fentanyl/