These are GCMS lab test results from DEA Licensed lab, sometimes they come from international labs like and as well.
A capsule of)" sent in from Houston, TX, sourced from China, that tested as. While is notorious for ODs, apparently it was temporarily placed in the US Schedule I by emergency scheduling in 1985 due to concerns about its potential for abuse as a designer drug. This placement was allowed to expire and benzylfentanyl was formally removed from controlled substance listing in 2010, after the DEA's testing determined it to be "essentially inactive" as an opioid.
Benzylfentanyl binds to the mu opioid receptor around 200x less strongly than fentanyl itself. It has about half the potency of orally administered morphine. Based off this comparison, the minimum lethal dose would be around 400 mg, but in case of hypersensitivity, 120 mg could bring sudden death.
You can purchase test kits from DanceSafe.org