Yes, there was an independent report ( book length ) by a chemical engineer, who was hired by the courts as an independent investigator. I will try to find a copy online, but this was all before scanners and the Internet, of course.
My post is from my personal knowledge. I was an internal consultant at the corporate level, for Union Carbide, over all automated manufacturing new technologies worldwide. So I worked with similar experts in chemical engineering, nuclear engineering ( UCC ran Oak Ridge National Laboratory ), computer science, industrial engineering, construction ( we built the Alaska pipeline), etc. So we worked together and discussed all sorts of things. And we reported directly to Warren Anderson, president of Union Carbide.
The government of India arrested Mr. Anderson and essentially held him for ransom. They were anxious to cover up any sabotage for political reasons, and also wanted to reach into the deep pockets of Union Carbide, which at the time was about the 10th largest corporation in America. I am quite familiar with what actually happened in other infamous industrial disasters, such as Three Mile Island, Chernobyl, Fukushima, .... and what did not happen, but what the public believes.
My father was product manager for Shell Chemical agricultural pesticides, so I have a smattering of direct knowledge of DDT, 2-4-5T, and many exotic neurotoxins and enzyme deactivators which were non-polluting but frightening to the public and were banned in the 1960s. We used all those things on our large working farm.