Posted by Samsaranda on 17/02/2022 10:28:09:
I seem to remember that Trichloroethane, which we used copious amounts of for degreasing in the Air Force, was found to be absorbed through the skin and could cause nerve damage. Remember working with it in a very confined space and ending up a bit high from it. Dave W
'Trike' is Trichloroethylene rather than Trichloroethane, though I can imagine chaps told to clean degrease metal didn't know they were dealing with two different chemicals. Both are dangerous.
Though Trichloroethane was used as a degreaser, and isn't particularly poisonous, it damages the Ozone Layer indirectly causing skin cancer especially in sunny countries. Also widely used as a solvent in glues etc. In high-concentrations it's a euphoric narcotic and has bumped off many glue sniffers because high concentrations cause arrhythmia and cardiac arrest.
Trichloroethylene was very extensively used as a degreaser. It's one of those chemicals that seemed safe at first, but large-scale use revealed problems. In high concentrations it causes narcosis and anaesthesia. As an anaesthetics safer than Chloroform, but phased out because modern alternatives are less likely to harm the patient. In ordinary concentrations: workers have become addicted to it; headache; drowsiness; plus eventual liver damage and increased risk of cancer in later life. Severe exposure causes death due to heart failure.
Always worrying in 'Dangerous Properties of Industrial Materials' is when a LD₅₀ (Human) figure is given. It means a large number of fatal accidents allowed the data to be collected. LD₅₀ (Human) for Trike is 857mg/kg body weight but 110 parts per million in air causes irritant effects after 8 hours. Interestingly people are more sensitive to 'Trike' than the rats, mice and dogs killed to determine LD₅₀ in lab experiments.
LD₅₀ is a measure of toxicity. It's the Lethal Dose that kills 50% of an exposed population. People aren't equally sensitive to poisons, which means anecdotal evidence about them is carp. Just because one thicko lived to tell the tale after a lifetime splashing in Trike doesn't mean everyone else is safe! For the truth to emerge from statistics at least a 1000 samples are needed.
Smoking whilst using Chlorinated Hydrocarbons is extra dangerous because some of the fumes are converted into Carbonyl Chloride, better known as the Chemical Weapon Phosgene. LD₅₀ (Human) is 3200mg per cubic metre of air.
Occasional small quantities of Trike used in a well-ventilated no-smoking workshop wouldn't worry me at all. Regular exposure to large quantities in a confined space is likely to cause health problems, some of which like cancer take years to develop. There's a possible link to Dementia. Pregnant ladies should always avoid it.
Dave