The reason they sued Monsanto was that Roundup was the Chemical used, not another brand. Monsanto also developed the chemical in the first place and held the patent for a number of years. Once the patent expired then more companies produced their own brands using the same active ingredient.
That you for many years used the chemical without any known ill effects does not prove the safety of it. That would be like saying “I smoked Tobacco all my life and I didn’t get sick” and then using that experience to say it doesn’t cause cancer when for others it has/did.
The scale is based on the known evidence. When you studied the scale the evidence pointed to the safety level you quote. The case involving Roundup is going to be appealed and perhaps more evidence will be made available during that process. Certainly the Cancer Council CEO has made clear that there may be information held by Monsanto that has not been released, and this could be like the Tobacco and Asbestos Industries concealment of the dangers of their products. Only in time this may be clear if this has been the case.
As to your detail on Creosote, there have been studies of Swedish, & Norwegian workers who dealt with Creosote thar showed “found a standardized incidence ratio (SIR) of 250 for lip cancers and an SIR of 237 for non-melanoma skin cancer”. That study is cited as “Karlehagen S, Andersen A, Ohlson C, ‘Cancer incidence among creosote-exposed workers’, Scandinavian Journal of Work, Environment and Health, vol 18, pp 26–29, 1992.”. There is also a Finnish study of similar exposed to Creosote workers that found “elevated risks for lip cancer, SIR = 306, and non-melanoma skin cancer, SIR = 464, were found for round-timber workers” that is cited as “Pukkala E, Cancer Risk by Social Class and Occupation: A Survey of 109,000 Cancer Cases among Finns of Working Age, Karger, Basel, 1995”. Historically it has also been found that Chimney Sweeps had increased incidence of cancer of the scrotum, the reason this is linked is that Soot contains the same chemicals that are in Creosote and as they worked they came into contact with the residues in the soot…
From Safework Australia (The Federal Workplace Health and Safety organisation) is this quote:
"Single epidemiological studies suggested a possible risk for bladder cancer, multiple
myeloma, and lung cancer due to exposure to creosote. Two case-control studies suggested
an increased risk of brain tumours and neuroblastoma among offspring of male workers
with possible creosote exposure.
All of the epidemiological studies were based on qualitative estimations of exposure rather
than on measurements. There is consistent evidence from human studies that creosote
causes skin cancer, but the studies do not allow dose-response analysis"
Creosote is known to increase the way the skin becomes more Photosensitive (ie the way that the skin becomes more sensitive to the effects of Ultra Violet Radiation) and this effect then creates a higher risk of development of skin cancers.
So it has been labelled as Category 1B (May cause cancer) and the IARC report that the Wikipedia article/entry somehow couldn’t find a citation for is easily located and is “International Agency for Research on Cancer, IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Volume 92: Some Non-heterocyclic Polycyclic Aromatic Hydrocarbons and Some Related Exposures, International Agency for Research on Cancer, Lyon, 2010”.
Creosote is dangerous and workers who use it must be monitored to ensure their safety and reduce the risks of getting cancers and a number of other well known effects including poisoning (fatal dose for a child is 1 to 2 grams and in Adults about 5 to 7 grams).
Some cancers are now able to be treated with a large degree of success and others are still difficult to deal with but the results for many have indeed improved. The mechanisms that cause cancer in some cases have been well established but the cures can still be hard to produce. Even Melanomas can now be treated with a much larger degree of success with new drugs that have only become available in the last few years with more still in trials and so not yet released for public treatment.