I searched for “benzene” posts on this forum and took note of the dates referenced in them.
8/2021 “Benzene in Butane”
9/2021 “Benzene in Kush Supply / Kush Co / Greenlane / Gas Innovations / Diversified”
2/2022 “Benzene Contamination Lawsuit” (page 4 of the suit references delivery of contaminated gas in August, 2021)
9/2022 “Benzene in my Badder”
3/2024 “It’s back and worse than ever” (author writes of contaminated gas from 3 different Cali vendors over the last 6 months, with the problem starting in September of the prior year.)
Add to that list: 3/2024 Though not referenced on this forum, a Michigan testing lab sent letters to clients warning of benzene contaminated butane in March 2024.
The timing of these problems is not random. The problems always start in August / September. That is the timeframe of the start of “winter gasoline” season.
Summer blend gasoline is produced from mid-April through mid August, with availability at gas stations from May 1 trough September 15. The permissible vapor pressure of summer blend gasoline is low to decrease the amount of gasoline that escapes/vents off during vehicle fueling. Summer blend gasoline is typically 2% butane.
Depending on which source cited, winter blend gasoline varies from 5 - 10% butane content. It’s produced from mid-August through the end of April. Regardless of 5% or 10% butane, when winter blend gasoline is in season, the requirement for butane in fuel increases significantly and refineries no longer have the luxury of being able to reflux their industrial butane to higher purities.
Nobody cares what impurities and contaminates are in the industrial grade butane that goes into gasoline. Professional extracting facilities must get their end-product tested for BTEX and other contaminates and need to be keenly aware of the chemical footprint in the solvents they use.
Who knows for sure if contaminated butane will hit the market in 2025. It did in 2021, 2022, 2023 & 2024.