The story so far…LCN first flagged up the emerging longterm problem of the unusually high incidence of cancers in retired firefighters in our June 2018 issue (https:// www.laundryandcleaningnews.com/ features/featureprotection-throughdecontamination- 6241957/), which featured the research at the University of Central Lancashire (UCL). This found that firefighters up to the age of 75 face a risk of death up to three times that of the general population. We described the characteristics of fire wear contamination and the technology for its effective removal.
In our issue of January 2020, we mentioned excellent complementary work in the US by the National Fire Protection Association (NFPA) (https:// www.laundryandcleaningnews.com/ features/featuresuccessful-launderingof- fire-wear-calls-for-professionalprocessing- 11318486/).
BBC News in September 2019 (https://www.bbc.co.uk/news/ukengland- 49811603) broadcast the findings of further research at UCL in the UK on individual cancer risks. We now know, for example, that the risk of testicular cancer had been found to be over double for firefighters, compared with the rest of the male population. In some US states there was now a presumption of liability for fire services faced with claims from firefighters affected by the illnesses listed. Leading fire services and workwear manufacturers in the UK and worldwide are know reacting strongly to this research, and launderers and rental operators need to respond appropriately.
Fire wear design
The leading suppliers of fire wear have made great strides in recent years to magnify the protection it offers to wearers, with particular emphasis on heat transmission and penetrability by smoke and fumes, liquids, micro-particles and tiny fibres (including glass and asbestos). Fires emit a wide range chemicals and other matter, many of which can cause harm, and the garment designer must consider every point of entry to avoid contact with the human skin. The result has been technically complex multi-layer assemblies which use the latest developments in fibre and textile design and in garment construction.
Leading manufacturers have also taken cleansing into account, with some of the best now backing this up with a specialist decontamination service, drawing on the latest low-temperature technology for effective washing and disinfection. As a result, it is now possible to remove well over 90% of the contamination acquired, even in severe industrial fires, provided cleansing is carried out promptly and expertly after each exposure. This month we look again at how to do this.
The main risks
Industrial and commercial fires, and even some domestic ones, expose firefighters to inhalation of a wide range of contaminants released when the fabric of buildings and their contents are burnt at high temperatures. The collapse of buildings frequently releases fibrous matter which might contain both glass and asbestos. It is not realistic to try to analyse which contaminants pose the greatest risk, because there are too many for this to be helpful. Manufacturers have rightly concentrated on producing garments which inhibit passage through the garment of vapours, liquids, micro-particles and fibres.
This protection is enhanced by one or more layers which guard against heat, in the form of flame, radiation or very hot vapour. This is a demanding set of performance criteria, so it is hardly surprising that modern fire wear is far more complex than it used to be. Also, the risk of inhalation of potentially carcinogenic gases formed by high-temperature combustion (and of inhaling hazardous fibres) makes it far more important to use breathing apparatus in an increasing number of fires.
There is also the secondary risk of a firefighter donning a protective garment which has not been effectively cleansed after a previous use. This could well expose the new wearer to the risk of inhaling micro-particles or fibres, especially when putting the garment on, as well as brushing their skin with old oily, greasy or liquid contamination of unknown content or hazard.
Many people might feel there is a risk of over-reaction to the risks described, but the magnitude of the conclusions of the university research, both in the US and the UK, is considerable. Justified claims of a threefold in increase in early death in retirement and up to double the risk of particular cancers should not be ignored. Provision of the correct workwear to every firefighter and decontamination after each wearing will inevitably increase slightly the operating cost of every fire station, but this requires a decision at the highest level (for example, the Home Office in the UK) to meet this cost. It is worth noting that the food industry in the UK faced a recent dilemma with the risk of residual allergen contamination of operatives’ workwear. This led to the development of processes and quality assurance techniques which lowered this risk to a negligible level (achieved by the workwear rental sector and food suppliers working in tandem, without government legislation or intervention).
Equipment required for successful decontamination
Research carried out so far suggests very strongly that the most appropriate machine for decontamination of modern protective fire wear is a fully programmable washer extractor. ‘Fully programmable’ means with the flexibility to vary number of stages, dips, bath temperatures, number and quantity of wash chemicals, speed and direction of rotation (including dwell times) and final extract (speed and time). There are many washer extractor models on the market worldwide which could meet this requirement.
The ability of a domestic washing machine design to decontaminate fire wear effectively would be very limited, because of programme flexibility, cage size and very restricted chemical dosing facilities. A tunnel washer would also be less suitable, because of the difficulty of varying mechanical action or wash chemistry for successive batches. The requirement for a professional washer extractor and process would probably make it impractical for decontamination to be carried out at the fire station.
Drycleaning using conventional solvents such as perc or hydrocarbon would certainly be effective in removing oily, greasy organic contamination but would be less effective for heavy metals (such as mercury, cadmium and cobalt) and their salts. Liquid carbon dioxide has been trialled in the US as an alternative drycleaning solution, with very encouraging results which indicate its cleaning performance is superior to washing in water or drycleaning, but this could change once more research has been carried out.
Chemicals required for effective decontamination
As with all workwear, the wash process must be capable of removing social soiling from blood, sweat and vomit as well as drink and soup spillages containing vegetable dye stains and fatty proteins. Vegetable dyes call for controlled oxidation (peroxide rather than hypochlorite) and fatty proteins require an emulsifier with an HLB (hydrophilic-lipophilic balance) value that encompasses the range of oils and fats anticipated.
The process must also address the wide range of industrial greasy, oily, tarry substances (and their thermal breakdown products) which can be expected. Many of these are known or suspected carcinogens, so removal must be as complete as possible. A wide range emulsifier should handle both these and the fatty proteins previously mentioned, because the HLB value for any particular contaminant will be unknown.
The mechanical action in the wash process should get the particles and fibres off the fabric surface, but these must then be held in suspension by the wash chemistry to prevent the otherwise unavoidable redeposition back onto the clean fabric (where they would be held by strong electro-chemical forces). This calls for enhanced suspension power in the wash chemistry.
The wash process must also achieve disinfection to prevent odours and to inhibit bacterial or viral transmission to the next wearer. It is very unwise to rely on implied thermal disinfection for this, because holding the wash stage at high temperature could well limit the life of the expensive, multi-layer construction required to achieve protective performance. The process needs low-temperature accelerators to get the disinfection chemistry to function at a maximum of around 40C.
Chemical suppliers worldwide will almost certainly recognise all of these requirements and be able to produce formulations to meet them. There should be little or no research needed for this. The critical step here is to convey the urgent need for improvements in fire wear decontamination to be set in train. The Home Office and the fire-worker representative bodies need to know exactly what to do. Specialist manufacturers might also need to gear up to meet the potential demand.
Special precautions when processing fire wear
The hazardous materials removed in a well-designed and executed fire wear decontamination process should not be discharged to drain untreated, because they could well contain asbestos fibres (some species of which are very potent carcinogens) and other undesirable materials. The water industry in the UK is still discharging substantial quantities of untreated sewage into rivers and the sea, so the potentially hazardous contamination is not something that can be dealt with by relying on pre-treatment at the sewage works.
The simplest method for a specialist laundry to deal with solid particles and fibres is to instal a settlement stage prior to final discharge to drain. This should be adequate to allow separation of solids and fibres, which will form a layer of sludge as they settle to the bottom of the tank or settlement pit. In designing this, it is important to do some simple settlement tests to determine the minimum time needed to achieve effective separation. The contaminated sludge may need to be removed as hazardous waste by appropriately equipped contractors.
The key to good separation is to keep any flow through the settlement tank very slow and uniform, so that it creates minimum disturbance with no ‘fasttracking’ (for example, warm liquors must not be allowed to rise towards the top of the tank and flow at a faster rate over the cooler lower layers). If the settlement time is found to be say four hours, then it could be necessary to instal sufficient tankage to retain eight hours production of drains liquor in two tanks. Once the first tank was full, it would be left undisturbed to settle, whilst the second tank took the next four hours production. The first tank would then be emptied to sewer ready to take the next four hours’ production and so on. If any oily matter floated to the surface, this would need to be racked off for separate disposal, like the sludge.
Conclusion
Fire-fighters have a highly responsible task, which is sometimes fraught with immediate danger. The surprising feature of the latest university research addressed here, is the long term hitherto unseen danger of potentially fatal disease in later life, which appears to be peculiar to firefighters. Getting their workwear in an assuredly safe condition for multi-use is one step that the workwear rental sector can take now – it has both the equipment and the chemistry to achieve this. It might not be the only step (increased reliance on breathing equipment might also be needed), but it is the logical next step and should not be dismissed.
