Chemeng Culture – Issue 1007

Chemical engineering on TV: Toxic Relationship

Sam Baker speaks to former process safety engineer Tony Cox, the expert witness portrayed in the hit Netflix series Toxic Town

AFTER beginning his career as a process safety engineer in the mid-1970s, Tony Cox always intended to work well beyond the usual retirement age, becoming self-employed in the 1990s as an expert witness. Now 78 and still working, he experienced an unexpected career twist in February – watching a dramatised version of himself on screen at the London premiere of Netflix’s latest hit series, Toxic Town.

A four-part dramatisation of the Corby toxic waste case, Toxic Town follows a group of mothers who took Corby District Council (CDC) to court, alleging that the council’s haphazard land remediation efforts on the town’s former steelworks site in the 1990s caused birth defects in their unborn children.

Cox doesn’t enter the show until episode four – the nail-biting courtroom finale in which his evidence proves that toxic dust from the steelworks site reached the mothers’ homes, providing the smoking gun to deliver justice for the 18 families.

Before production company Broke & Bones approached Cox in 2023 to interview him for their research, he was given a heads-up by Collins Solicitors – the “heroic law firm” as he calls them – who represented the Corby mothers, that Netflix were planning to dramatise the case. “When I first heard about the idea, I was dead against it”, he says, fearful of doing wrong by the mothers whose four-year legal battle ended in 2009, 24 years after the birth defects are thought to have started.

Cox nonetheless signed the slip of paper saying he was happy to be portrayed in the drama and proceeded to tell the producers everything about his involvement in the case. “My part, as an expert witness, was always going to be the one the dramatists were going to latch onto because it was a nail-biter for the lawyers.”

The tension was provided by evidence that completely countered Cox’s. An expert witness instructed by CDC asserted that the toxic dust could not have travelled as far as the affected families’ homes and therefore could not have caused the birth defects. Their results were presented to the judge in what Cox remembers as a “very solid-looking report”.

Even after thoroughly examining each other’s reports in an out-of-court meeting, the contradictions remained. “We couldn’t reconcile our different positions,” says Cox. “The approach we were each taking was, in principle, identical, but the results we were coming up with were significantly different. It was an absolute toss-up, 50-50, which one of us was right, so as courtroom drama goes, it was the obvious choice.”

Neither Cox nor the mothers’ lawyers ever doubted his expertise. After all, his PhD was in modelling industrial air pollution, and in 1975 he developed one of the first mathematical models for pollution dispersion in air. But Cox remembers feeling nervous that his pencil-and-paper method could have innocuously led to a simple error in his calculation.

It transpired that Cox’s model was flawless, and the error instead lay in the defence expert’s report. Their model relied on equations employed in an old piece of contract research work by the International Energy Agency Coal Research project in 1994, which itself used an equation from an obscure paper from 1992 written in German.

The mothers’ lawyers tracked down the paper within 24 hours, depicted in Toxic Town by frantic phone calls using broken GCSE-level German. Cox realised that an exponent in the “German equation”, as it came to be known, had been lost in translation when used in the coal research report. Hence, the defence expert underestimated the distance the toxic dust could have been dispersed by a factor of three to five.

Cox remembers that the defence expert “performed impeccably” from both a scientific and a legal point of view, and that they immediately accepted their error once he had pointed it out. “The case as a whole was a model of how scientific expert evidence should be handled in a legal context.”

Still with his expert witness hat on, Cox was “pleasantly surprised” with Netflix’s retelling of events. “They portrayed the essence of the story very well,” he says. “The right weight was put on the right issues.”

The quality of the drama did little to dampen how “spooky” it was to see himself played by an actor, however. “I was probably portrayed a little bit more geeky than I actually am,” he says, mirroring the thoughts of countless scientists and engineers who have been portrayed on screen.

From Cambridge to Corby

Prior to working as an expert witness full-time, Cox spent the best part of 15 years working in process safety. After completing his undergraduate degree in mechanical engineering at Cambridge University in 1968, followed by an environmental science PhD at Imperial College London, he worked for engineering consultancies at oil refineries and gas terminals. He then moved to offshore facilities after the Piper Alpha fire in 1988. “Nearly all my early professional work from 1975 to about 1990 was doing process safety assessments of that kind of heavy process plant,” he recalls.

In 1994 he made the decision to “reinvent” himself. “I decided I wanted to work on my own as an independent consultant, and the field that I thought was the best prospect was doing legal expert witness work.”

The first case he worked on involved a British Army cook in the Gulf war, whose legal team had instructed him in a personal injury claim against the Ministry of Defence. His practice then started to pick up work on cases involving major industrial incidents – “things that had a technological element that was beyond the average safety expert”. Over the years he has been instructed in cases surrounding the Piper Alpha disaster, the 1999 Ladbroke Grove rail crash, the 2005 Buncefield explosion, and safety failures at the Elsenham railway level crossing in Essex.

The role of expert witnesses in legal proceedings is heavily debated, largely down to the fact that they are not paid and instructed by the court but instead by either a claimant or defendant’s legal team. In the 1970s, Cox says “it was all too common for judges and lawyers to complain about experts who had stuck rigidly to their incorrect theory”. Cox believes that such “hired-gun experts” are far less influential now, and that the Corby litigation was an exemplary show of “where the law and scientific practice engaged with each other in such an admirable way”.

Cox hasn’t looked back since becoming a full-time expert witness and continues to find the challenge exhilarating. “The discipline of being challenged by a lawyer is really not like the discipline of being challenged by one of your own peers,” he says. “You have to figure out in real-time what the truth actually is to a question you’ve never been asked before” – often posed by a partisan barrister with little technical understanding of science and engineering.

“When it all works as it should,” Cox concludes, “the outcome is definitely better justice, and I do get a buzz out of reflecting on my contributions to past cases, notably Piper Alpha, the Ladbroke Grove rail disaster, and of course the Corby group action.”

Who knows, perhaps Toxic Town won’t be the last time we see Cox – or a geekier version at least – gracing our screens.

Toxic Town is available to watch on Netflix