A former American football player, coach and cancer survivor has questioned why crumb-rubber infill is not being replaced by other materials in the UK, as is set to happen in the European Union.

“If there is just a simple change,” said Malik Mustapha, “of substituting the material out from the crumb rubber in 3G pitches to something like cork, what’s the big deal? Why aren’t we doing it?”

Six years ago, Mr Mustapha was diagnosed with non-Hodgkin's lymphoma, a cancer of the lymph system. At the time his haematologist, he recalled, put it down to “bad luck”. But he has wondered, since, if there could have been any cause for his getting this cancer so young.

As exclusively revealed in The Herald, a recent report by Professor Andrew Watterson of the University of Stirling, which highlighted health and environmental concerns around the granules of shredded end-of-life tyres used as infill in 3G pitches, made him wonder whether there might be a link between his cancer and the crumb.

The report called for a ban on crumb rubber in Scotland, in line with the European ban on the material as infill from 2031. It drew attention not just to carcinogenic chemicals in the infill, but also the presence of endocrine disruptors that can affect reproductive function.

It said: “Crumb rubber contains a wide range of carcinogens and it should be noted that the control levels set for these are always ‘acceptable’ levels and not ‘safe levels’ – acceptable to regulators with the risks then run by workers, users and the wider public- because there are no safe levels for carcinogens.”

However, official advice often states that 3G pitches are safe.  Sometimes cited in defence of infill is a 2020 pan-European report published in the journal Science of the Total Environment, which found “cancer risks for exposure to polycyclic aromatic hydrocarbons [the chief carcinogens of concern] were below 1:1 million” and that there were “no health concerns for synthetic turfs with ‘end-of-life' tyre-derived infill”.

This, said Professor Watterson, only looked at the impact of polycyclic aromatic hydrocarbons, and did not cover the rest of the almost “200 carcinogens” found in one study to be in crumb.

READ MORE: Ban toxic 3G crumb rubber pitches in Scotland, says report

READ MORE: 3G pitch ban could harm provision of sports facilities

READ MORE: Call for ScotGov to investigate Scotland's 3G pitches

Malik Mustapha was certainly heavily exposed to the crumb. As a defensive lineman in American football, he frequently had his hand down on the ground and in contact with the granules. “You’re tackling people to the ground,” he said, “so you’re sort of rolling in it. By the end of practice, those little crumbs are everywhere. They’re down your trousers, they’re in your shoes, they’re in your hair. They’re everywhere. It’s not like football where you do the occasional slide tackle now and then and you’re running about. We spent a lot of time on the ground.”

After practice, he recalled, he would sometimes have touched his face and his mouth. “You would think nothing of it. You would think it’s a bit of a nuisance. You would get changed at the front door, not in the house – that's the biggest nuisance."

Frequently he would find the granules in his gum shield. “You would do a tackle, you would been down on the ground and they would be in your gumshield. Talk about prolonged exposure in a place where you can absorb it! If you get it in your gumshield it’s rubbing up against your gums. Then when there was break in the play you could spit it all out."

The Herald: Malik Mustapha, American football player and cancer survivor. Photo Gordon Terris.Malik Mustapha, American football player and cancer survivor. Photo Gordon Terris. (Image: Newsquest)

One of the reasons that Mr Mustapha has asked himself whether there might be any cause to his cancer is because the form of non-Hodgkin's lymphoma, (presenting in the testicle) is extraordinarily rare in the young – and he was 25 when diagnosed.

“I had diffuse large B cell non-hodgkin's lymphoma. It initially presented in my testicle and I thought it was testicular cancer. I had to have that surgery to remove that tumour. But then they said it was Non-Hodgkin's lymphoma, and when you look at studies of that, when it presents in that way, there aren’t many cases of it happening in people below 40, the majority are in their seventies, and there I was only 25.”

The two years running up to his diagnosis, he observed, were those during which his regular play and training had shifted from grass to 3G crumb pitches. “I’ve sometimes asked why did it happen then in my life? That’s why that report made me ask questions. That was the first time I had prolonged exposure continuously."

Mr Mustapha played regularly on 3G pitches for two years from 2014, as a player for Stirling Clansmen, and back then regarded it as a privilege compared with grass. Sometimes he would be on 3G surface three or four times a week. 

The Herald: A University of Stirling report highlighted health and environmental concerns around the granules of shredded end-of-life tyres used as infill in 3G pitchesA University of Stirling report highlighted health and environmental concerns around the granules of shredded end-of-life tyres used as infill in 3G pitches (Image: Newsquest)

On diagnosis at 25,  he wondered if the cancer's cause could have been that he was overweight – but his doctor dismissed that theory. After his diagnosis, Mr Mustapha moved down to Cambridge to be with his family for a while. He had six rounds of chemotherapy as well as some in-patient treatment, starting in November, and by the end of December, the cancer was gone.

Mr Mustapha returned to American football, and he has played on multiple 3G pitches since then. “I’ve now got two children,” he said, “which is quite something because when I had one of my testicles removed, and one of the recommended treatments for the lymphoma was to irradiate the remaining testicle that was there to reduce the risk. I opted not to  do that because I wanted to have children at some point and it would ruin the chances of that.”

The question of whether crumb rubber may be behind some cases of cancer has not yet been laid to rest.

As someone who spent a lot of time in contact with the crumb, Mr Mustapha is among a particular subset of players that would be more likely to experience any harmful effects it might have. Also in this group are rugby players and soccer goalkeepers.

The possibility that goalkeepers might be more impacted has been the focus of campaigning by American coach, Amy Griffin for 15 years, since she started to notice what she believed to be a pattern of excess cancer in the group. 

The list she kept of goalies and other players with cancer became the trigger for a Washington State investigation.  That  2017 study concluded that  “exposures from crumb rubber are very low and will not cause cancer among soccer players.” 

However that investigation had its critics, including Richard Clapp, an American epidemiologist and cancer expert, who said the report's "language represents false reassurance based on faulty logic and methodology".

He told the Herald: “I don't think there has yet been a proper epidemiological investigation of the health risks of playing on crumb rubber pitches. There may be some underway in Europe, but those are not yet published to my knowledge. The studies in the US are inadequate or, in some cases, deeply flawed. The best we have to go on are hazard assessments which consider the mix of toxic and carcinogenic substances present in the artificial turf and infill materials.”

“Because there are suitable alternatives to synthetic turf, I think the proper health-protective approach is to pause further installation of turf fields. This is based on hazard assessment. We don't need to go further down the synthetic turf/infill path at this point.”

Some scientists therefore are questioning why, given there are other options, many countries are persisting with crumb. “Crumb rubber and other toxic infill materials... are easily avoidable,” he said. “If we don't have to expose people, especially children, to carcinogens then let's not. Cancer is widespread already, so why add to that burden by allowing even small amounts of carcinogens into the environment unnecessarily?”