Just cuz you hear GW talk these things, you guys fail to acknowledge that he is an accredited scientist who knows there's more than one way to skin a cat. So he has numerous methods that may be employed to get that purged out and he should be warning you if you vape hexane residues what kind of damage will be done to your body when using toxic solvents to obtain these desired compounds of interest.
Here you go! It looks to me like sensory threshold is 130 ppm and the LC-50 is about 25,000 ppm. It tastes and smells like gasoline at about 1/2 of one percent of LC-50, so it should be easy to avoid underpurged oil.
https://www.sciencelab.com/msds.php?msdsId=9927187
Section 11: Toxicological Information
Routes of Entry: Absorbed through skin. Dermal contact. Inhalation. Ingestion.
Toxicity to Animals:
WARNING: THE LC50 VALUES HEREUNDER ARE ESTIMATED ON THE BASIS OF A 4-HOUR EXPOSURE. Acute oral
toxicity (LD50): 25000 mg/kg [Rat]. Acute toxicity of the gas (LC50): 48000 ppm 4 hours [Rat].
Chronic Effects on Humans:
MUTAGENIC EFFECTS: Mutagenic for bacteria and/or yeast. May cause damage to the following organs: peripheral nervous
system, skin, central nervous system (CNS).
Other Toxic Effects on Humans:
Very hazardous in case of ingestion, of inhalation. Hazardous in case of skin contact (permeator). Slightly hazardous in case
of skin contact (irritant).
Special Remarks on Toxicity to Animals: Not available.
Special Remarks on Chronic Effects on Humans:
May cause adverse reproductive effects based on animal data. May be tumorigenic based on animal data. May affect genetic
material. Passes through the placental barrier in animal.
Special Remarks on other Toxic Effects on Humans:
Acute Potential Health Effects: Skin: May cause mild skin irritation. It can be absorbed through the skin in harmful amounts.
Eyes: May cause mild eye irritation. Inhalation: May be harmful if inhaled. Inhalation of vapors may cause respiratory tract
irritation. Overexposure may affect, brain, spinal cord, behavior/central and peripheral nervous systems (lightheadness,
dizziness, hallucinations, paralysis, blurred vision, memory loss, headache, euphoria, general anesthetic, muscle weakness,
numbness of the extremeties, asphyxia, unconciousness and possible death), metabolism, respiration, blood, cardiovascular
system, gastrointestinal system (nausea) Ingestion: May be harmful if swallowed. May cause gastrointestinal tract irritation
with abdominal pain and nausea. May also affect the liver, blood, brain, peripheral and central nervous systems. Symptoms of
over exposure by ingestion are similar to that of overexposure by inhalation.