Emergency decontamination units used in previous flood defence operations were among those axed in Government cuts, the Press Association has learned.
And union chiefs have ordered a health and safety review over concerns firefighters called out to deal with chemical spills or fires involving hazardous materials could face delays in being decontaminated.
Critics had already warned the decision to remove from service a third of the Incident Response Units (IRUs) equipped to deal with a "dirty bomb" and other major incidents posed a terror risk with "disastrous consequences for human safety".
Now there are fears it has compromised the capacity to deal with the sort of devastating floods which hit parts of the UK over Christmas.
Shadow home secretary Andy Burnham said: "I urged ministers to put these plans on hold last month but they axed a third of these emergency vehicles at the height of the floods.
"Yet again, David Cameron's crude cost-cutting hindered the country's ability to cope with flooding.
"The plans were hatched in secret, without any public information or consultation. Ministers must make a statement to Parliament about the impact of this decision on the country's ability to respond to national emergencies."
Deployments of the scrapped Incident Response Units (IRUs) were revealed by the Department for Communities and Local Government (DCLG) in response to a Freedom of Information Act request by the Press Association.
Logs showed one of the units taken out of service on December 31 - based at Bovey Tracey in Devon - was used for "decontamination of firefighters and other agencies" during the massive floods that affected the Somerset Levels and other parts of the West Country in 2014.
Another was sent twice from the fire station at Godstone, Surrey, "to assist the Environment Agency with erecting dams" as the South East also struggled to cope with burst rivers.
IRUs based in Wimbledon and in East Greenwich, London - among the four of the capital's 10 units being scrapped - were sent to provide shelter using tents designed to house showers for mass decontamination.
Units were also deployed in 14 "hazmat" incidents in the last two years - being called on to decontaminate firefighters in four cases and provide lighting to assist their work in another.
Half of those were in Cambridgeshire, where the axed IRU at St Neots was on "pre-determined attendance".
Fire Brigades Union general secretary Matt Wrack said that raised questions about what cover would be in place in areas that included the units as part of their standard response.
He told the Press Association he would ask FBU health and safety officials to establish what action was being taken to ensure firefighters are not put at risk.
In another eight cases, units were sent out to fires and used once for decontamination of firefighters.
DCLG refused a request to release risk assessments of the cutbacks, carried out in conjunction with the Chief Fire Officers' Association (CFOA), on the grounds of "national security".
It concluded that 43 IRUs were sufficient "in order to meet the scale of event identified within the national resilience planning assumptions".
The 22 deemed surplus to requirements were taken out of service "almost immediately", it explained, because their power respirator protective suits (PRPS) were about to pass their expiry dates.
New suits are being bought for the units that remain in service.
The Government said the move would not compromise safety because it was "better to issue all front-line responders with the training to begin decontamination rather than wait for specialist services to arrive".
Mr Wrack said it appeared however that the cost of replacing the kit was a motivation for the scaling down, despite the UK's terror threat level being at "severe", meaning an attack is considered "highly likely".
In the event of a chemical or biological attack people "are going to waiting longer" to be decontaminated, he said, despite speed being a crucial factor in responding.
While it made "perfect sense" for forces to use the IRUs for non-terror responses, he said the withdrawal would leave forces having to find alternatives - still at taxpayers' expense.
"It's robbing Peter to pay Paul," he said
DCLG did not give details of how much cash the move would save in reduced central government funding to local forces for the operation of the IRUs, which were introduced as a national anti-terror measure in the wake of the 9/11 attacks on the US.
"The calculation will be made and the amounts for 2016/17 published later in the year," it said.
The move - which Labour said was made without consultation - emerged days before the axe fell in a CFOA briefing note leaked to Mr Burnham.
Disposal of the units is under review by the CFOA.
IRUs are equipped to provide mass decontamination facilities at incidents where large numbers of people have been exposed to chemical, biological, radiological or nuclear materials.
Showers, protective clothing and detectors are among the equipment on board the trucks, which are ready at all times to be taken out by specially-trained firefighters from local brigades.
:: The IRUs being axed are those based in: Alfreton, Derbyshire; Broughton, Buckinghamshire; Blandford, Dorset; Bovey Tracey, Devon and Somerset; Burton, Staffordshire; Canley, West Midlands; Cheltenham, Gloucestershire; East Greenwich, London; Godstone, Surrey; Hereford, Hereford and Worcester; Morecambe, Lancashire; Penzance, Cornwall; Plaistow, London; Slade Park, Oxfordshire; Southern, Leicestershire; St Albans, Hertfordshire; St Neots, Cambridgeshire; Stalybridge, Greater Manchester; Stanmore, London; Walsall, West Midlands; Wimbledon, London; Winsford, Cheshire.
A Government spokesman insisted that there was "no extra risk to the public through withdrawing the excess units".
Standard fire engine hoses were used in the vast majority of cases where firefighters' clothing and boots needed to be washed down after being in contact with contaminated flood water, officials pointed out.
The spokesman added: "Public safety is our number one priority.
"We are reducing the number of units which respond to contamination incidents because some of them are surplus to requirements.
"Research and experience shows that speed is of the essence in dealing with major incidents, which is why it is better to give all front line responders the training to begin decontamination straight away.
"Half of the units were not used in 2015 or 2014 and on those rare occasions they were deployed, they were not used in the type of incident for which they were commissioned."