Firefighters have called for more protection after research found they were being exposed to dangerously high levels of harmful chemicals.
Their plea echoed scientific research that said firefighters were at risk of getting cancer because of contaminated clothing and equipment.
For the first time, the UK's chief fire officer has acknowledged the high rate of cancer among his colleagues.
The Fire Brigades Union has called on the government to protect firefighters.
Union spokesman Chris Moore, a firefighter in South Shields, has himself been receiving treatment for an incurable cancer.
"Up and down the country firefighters are dying of this, due to them saving lives in the line of duty, and their job is killing them," said Mr Moore.
"The government needs to wake up and realise, 'OK there could well be a link here, in the interim term, while we work out what's going on, this is what we're going to put in place'.
"Give us better protective equipment. More of it, so when it gets dirty we put it away and we can put a clean fresh set on.
"At the moment we're having to turn out to fires with kit that's already dirty, because we've got one set in the washing machine and the one we've got is already dirty.
"We're there to protect the community. We need our employers and the government to protect us."
The government said it was vital every possible measure was in place to protect firefighters.
What does the science say?
Fire chemistry and toxicity expert Prof Anna Stec has called on the the government to protect firefighters by providing them with the best preventative medical care, education and support, while investing in guidance and research to ensure best practice was followed.
"In my opinion, there is a direct link between firefighters' occupation and cancer," she said. "Firefighters are twice as likely to die when compared to the general population - and they're dying from not one type of cancer, but they've got multiple types.
"Yet in the UK absolutely nothing is done to address, generally, fire toxicity or firefighters' health."
Prof Stec and her team of researchers at the University of Central Lancashire said firefighters' risk of developing cancer was increased by dangerously high levels of harmful chemicals remaining on their protective gear following exposure to smoke.
According to Prof Stec's research, firefighters' leading cause of exposure to carcinogens was not inhalation but absorption via the skin. That absorption automatically increased in hot environments that led to sweating and dehydration, meaning the firefighters became "a sponge for all the fire toxins".
Firefighting remained an unregulated occupation in the UK in terms of long-term health protection, according to the team at the University of Central Lancashire, and there was currently no national directive or standard to tell firefighters how their kit should be cleaned. Instead it has been left to individual brigades to decide for themselves.
Researchers have said the methods used to clean firefighters' protective clothing and equipment were not effectively implemented, which has caused protective gear to be contaminated for its next use, meaning the length of time that skin is exposed to fire toxins was increased.
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What does the UK's chief fire officer say?
The UK's chief fire officer Chris Davies said: "There is a lot of scientific and medical information out there but all of it, that I'm aware of, states that you can't prove or disprove a link to cancer.
"What I do acknowledge is firefighters are contracting certain types of cancer above the population norm, I accept that and that is a concern.
"What I want to stress is that we're not just sat back waiting, we are developing this all the time. It does sound frustratingly slow, I will acknowledge that, but the assurances that I want to give is there is an incredible amount of work going on in the background to make this happen as quickly as possible.
"But, I do acknowledge that that's not quick enough for some people."
'A macho culture'
Firefighters past and present have described a "macho culture" that once prevailed in the fire brigade.
Having dirty kit was seen as a "seal of approval" and a sign of firefighters having worked harder than their colleagues.
Breathing apparatus was described as heavy and difficult to service and those who wore it were often regarded as "wimps".
Firefighters often worked without the apparatus, earning them the nickname "smoke eaters".
Gerard Hollingworth from Bradford worked as a firefighter and a fire instructor and now has cancer of the blood.
He recalled still wearing dirty kit while having tea and cakes on his break after a training exercise.
"Looking back, it's now shortened my life," said Mr Hollingworth. "We've got firefighters getting cancer on all watches and all stations and things need to be done about it.
"I'm angry after all this time that it's going through Congress in America, yet nothing seems to be happening in the UK."
What next for the UK's firefighters?
In the United States, President Donald Trump has acknowledged a potential link between being a firefighter and contracting cancer, signing the 9/11 Victims Compensation Fund for first responders, meaning firefighters who had become sick from toxic exposure could claim health care compensation.
Research, believed to be the first of its kind in the UK, has started to analyse levels of contamination, with fire services having to opt-in to have their staff tested.
Firefighters in East Sussex, Hampshire, Essex, Kent, West Midlands and Staffordshire have provided samples for the research with results expected to be published at the end of 2020.
The Home Office said it had supported the National Fire Chiefs Council in establishing a health and wellbeing board focusing on prevention and early intervention.
A Home Office spokesperson said: "Our firefighters put themselves in harm's way to keep us safe, and it is vital that every possible measure is in place to mitigate the risks they take."
Inside Out examines rates of cancer in firefighters on BBC One at 19:30 BST on Monday 30 September and can also be seen afterwards on the iPlayer.