Operation Web Tryp
Operation Web Tryp was a United States Drug Enforcement Administration operation that ended on July 21, 2004 with the arrests of 10 persons. Its purpose was to investigate web sites suspected of distribution of unscheduled, unregulated tryptamines and phenethylamines of questionable legality.  This trade in "grey market" drugs, which were not explicitly illegal but potentially prosecutable as drug analogs, became known as the "research chemical" trade; a euphemism for the fact that the chemicals were being sold for human consumption rather than industrial or academic research.
Five websites were involved in Operation Web Tryp:
- www.racresearch.com (RAC Research), including the arrest of April Curtis.
- www.duncanlabproducts.com
- www.pondman.nu
- www.americanchemicalsupply.com, including the arrest of Mike Burton.
- www.omegafinechemicals.com
One of these websites, pondman.nu, was allegedly taking in U.S. $20,000 per week and grossed $700,000 before being shut down. Another, racresearch.com, reportedly grossed $500,000 in 14 months.
The DEA claims that AMT sold by pondman.nu caused the April 2002 death of an 18-year-old man in upstate New York, and that 2C-T-7 and 2C-T-21 sold by americanchemicalsupply.com caused the death of a 22-year-old Louisiana man. Fourteen other non-fatal overdose incidents requiring hospitalization were also cited by the DEA.
In December 2004, using credit card information provided by the DEA, British police arrested and charged over 20 UK residents who had purchased substances through the seized web sites.

# Legality
Although these chemicals were not scheduled, a long shadow was cast on their legality by the 1986 Federal Analog Act. This Act and the United States v. Forbes Colorado federal district court case stipulated that the burden of proof, in regards for the intention for human consumption, was on the government if any prosecution under the Federal Analog Act was to occur. Additionally, legal ambiguities regarding the legality of certain analogs of scheduled substances had been established in the aforementioned court case (In particular, the similarities of AET and DMT were debated).
As the Analog Act requires intent that a drug analog be manufactured or sold "for human consumption" before becoming prosecutable, it's possible that the people arrested in this operation could have escaped had they been more careful in how they promoted and represented their companies.  Many lapses of judgement or legal knowledge on the part of the web site owners and operators contributed to their downfall, such as the marketing of "sampler packs" containing what amounted to individual dosage units of drugs and aggressive promotion of their wares specifically as psychoactive drugs in various forums, such as Usenet.  Usenet readers repeatedly warned at least one site operator that they were going to run afoul of the Analog Law.
Whether another "research chemical" company could be viable in the US today is unclear.   While the legality of a carefully run operation may be defensible, it seems unlikely that many people would be willing to risk arrest and crushing legal costs to test the theory.  Similar businesses set up outside of the US continue to operate and ship "research chemicals" to the US in small amounts.