At least some of this is mentioned in the US court judgement linked to in the article: https://casetext.com/case/chevron-corp-v-donziger-28 (under the heading "Donziger Causes a Change to Less Probative Tests When the LAPs' Experts Find Pollution that Likely Was Not Caused by Texaco" and in subsequent and preceding sections). I think there may have been news coverage that went into further details, can't remember where though.
Thank you for that. I view the case a little more skeptically now. The stakes were high on both sides, and ergo the motivation to distort the process just as high. However, the motivation for Chevron to mitigate environmental impacts in the 70s/80s/90s were negligible, until lawsuits and stories like this provided the PR incentive. So I'm inclined to believe they are responsible for much - but perhaps not all - of the destruction. I think it's a little naive to think otherwise.
As I'm reading it no one is claiming they mitigated damage in the 70s/80s or that they didn't cause damage. They did however pay $40 million to fix some damage in 1995 and were granted indemnity by the Ecuador government in return. Some arguing on how good of a job they did but seems to have been at least somewhat decent. Other environmental damage was found but it likely happened after Chevron was no longer involved in the project. Together that means they're off the hook legally which is all that a lawsuit is about (rather than morals or ethics). Chevron covered its backside legally very well it seems to the point where the other side resorted to less than legal behavior.
The lawsuit was a class action by indigenous peoples against Chevron, and was separate to the agreement between Chevron and the government. There was plenty of financial incentive for both Chevron and the government to look away from the plight of the indigenous people.