PRODUCTS OF COMBUSTION

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1 Health Prtectin Agency Chemical Hazards and Pisns Divisin (Lndn) Lndn WC1V 7PP 24 Hr Tel: Incident Summary PRODUCTS OF COMBUSTION DRAFT SUMMARY INFORMATION Key Pints Health risks assciated with expsure t smke and txic substances released in fires is evident, but precise details are uncertain as smke frequently cntains a ccktail f substances, which changes with the temperature f the fire and thrugh interactin with ther pllutants 1 Prducts f cmbustin are likely t act as respiratry irritants and may cause cughing, chking, hypxia and pulmnary edema Cntact with prducts f cmbustin may cause skin and eye irritatin Prtective clthing and breathing apparatus shuld be wrn. In the event f a large fire, stay up wind and ut f lw areas. Stay indrs until plume has passed, ventilate clsed spaces This handut is prduced in cnjunctin with specific CIRS chemical infrmatin sheets, fr instance carbn mnxide (CO) and hydrgen cyanide (HCN) First Aid Terminate expsure and supprt vital functins The casualties shuld be mved t an uncntaminated area Rescuers shuld, ideally, be trained persnnel and must be careful nt t put themselves at risk and s wear apprpriate prtective clthing and, if available, respiratry prtectin If the casualty is uncnscius a clear airway shuld be established and maintained; give 100% xygen if available HPA Disclaimer: This guidance has been prvided by the Chemical Hazards and Pisns Divisin f the UK Health Prtectin Agency (HPA). It is general guidance based n current knwledge and understanding. The HPA des nt warrant that the infrmatin and guidance is cmplete and crrect fr use in all circumstances. The HPA shall nt be liable fr any damages that might be incurred as a result f the use f the guidance r infrmatin. Page 1 f 9

2 Inhalatin expsure: If the patient stps breathing then expired air resuscitatin shuld be started immediately using a pcket mask with a ne-way valve, if available. It is imprtant in cases where the face is cntaminated r where the expsure was by inhalatin that expired air resuscitatin is NOT attempted unless an airway with rescuer prtectin is used Intubate immediately if burns t face r neck r airway bstructin Give brnchdilatrs if brnchspasm ccurs Dermal expsure: If skin irritatin has ccurred, seek medical attentin and flush the area with water. In rder t prevent further tissue damage remving clthing Eye expsure: If eye irritatin ccurs seek medical advice as sn as pssible and irrigate thrughly with water r saline fr 15 minutes Detailed infrmatin 1,4 Smke cnsists f a mixture f gases, liquid drplets and slid particles representing the decmpsitin and cmbustin prducts frm fires. See Appendix 1 fr types f fires Txic prducts frm fires can be cnsidered in three catries (see Table 1 at the end f the dcument): Asphyxiants: A majr hazard inside buildings: simple asphyxiant gases ( methane, nitrgen) displace xygen causing hypxia, chemical asphyxiants interfere with xygen delivery and include hydrgen cyanide (HCN) and carbn mnxide (CO) which may be rapidly fatal Irritants: inrganic acid gases and rganic irritants. Smke irritants are imprtant as ptential causes f adverse health effects nt nly inside buildings but als in smke dispersed int wide pen areas Inrganic acid gases include hydrgen chlride (HCl), hydrgen brmide (HBr), hydrgen fluride (HF), nitrgen xides (NO x ), sulphur dixide (SO 2 ) and phsphrus pentxide (P 2 O 5 ) Organic irritants include frmaldehyde, acrlein and crtnaldehyde Irritants cause immediate sensry irritatin f the respiratry tract The severity f effect depends n the cncentratin expsed t and the slubility f the irritant in the smke. Thse with high water slubility tend t cause predminantly upper airway irritatin (e.g. hydrchlric acid), whereas thse with lwer water slubility may reach further dwn the respiratry tract and can lead t pulmnary edema which may be delayed (e.g. phsgene) Other symptms range frm mild eye and thrat irritatin, t severe pain and death frm respiratry arrest r laryngeal spasm at very high cncentratins. Unusual rganic prducts: Any chemical present in bulk r which is txic at lw cncentratins culd be released in the fire plume and may have imprtant shrt and lng term health implicatins (e.g particulates) As txic prducts may differ at varying distances frm a fire, it is simpler t cnsider the hazards in relatin t difference znes f prximity t the fire: Page 2 f 9

3 Zne 1 Clse prximity t the fire (i.e. within building). The majr risks are frm heat, txic smke and asphyxiant gases which may be rapidly lethal. Znes 2 immediately utside the fire zne (area depending n size f fire and chemical nature f hazard). The majr hazards are txic smke, irritant gases and particulates and any release frm bulk chemicals if present. Zne 3 the surrunding lcality. Hazards as fr Zne 2 but less prnunced. Summary f Human Txicity Fr specific txiclgical infrmatin n individual chemicals refer t relevant CIRS fact sheet Fr Risk Assessment f Expsure see Appendix 2 The mrtality rate fllwing smke inhalatin is between 45-78% [2] with mst deaths ccurring befre the patient reaches hspital usually as a result f carbn mnxide and/r cyanide pisning Smke and heat inhalatin can damage bth the airways and the lung parenchyma 3 Smke cnstituents can cause atelectasis by destructin f lung surfactant, and a cnsequent risk f pneumnia Smke can als damage the pulmnary capillary endthelium directly causing pulmnary edema and impaired gas exchange ften leading t pulmnary insufficiency 3 Acute Clinical Effects Irritatin f the eyes, nse and thrat may be fllwed by cughing and wheezing, dyspnea, sputum prductin and chest pain Brnchspasm, atelectasis, pneumnitis and pulmnary edema may ccur in severe cases Laryngeal edema, muscsal edema and slughing may ccur Management Inhalatin Management Maintain a clear airway, give humidified xygen and ventilate if necessary If respiratry irritatin ccurs assess respiratry functin, mnitr xygen saturatin and/r bld gases and if necessary perfrm chest X-ray Brnchdilatrs shuld be given if brnchspasm ccurs Fr carbn mnxide and cyanide pisning, see specific Carbn Mnxide and Cyanide infrmatin sheets Where methaemglbinaemia ccurs, give methylene blue if level is between 15-20% (avid in G6PD deficiency); discuss further management with a Pisns Infrmatin Service r a Chemical Incident Prvider Unit Symptmatic and supprtive care Investigatins 4 Carbn Mnxide level (see separate Carbn Mnxide infrmatin sheet) Arterial bld gases fr PO 2, A-a gradient and ph Page 3 f 9

4 Chest X-ray (relatively insensitive fr presence f smke inhalatin and pulmnary cmplicatins) Cyanide level (see separate Cyanide infrmatin sheet). There is n rapid assay available but suspect cyanide pisning clinically if the patient is slw t respnd t treatment r has a persistent acidsis Als cnsider: methaemglbin levels ECG if >40yrs Spirmetry r Peak Flw (requires full cperatin but useful as baseline if symptms develp later) Laryng/brnchscpy t evaluate the upper airway fr st depsitin Admissin Criteria fr Inhalatin Expsure Discharge hme: Asymptmatic patients, but they shuld be advised t return if symptms develp within hurs Patients with mild effects (what is mild) may be discharged, but if symptms recur r develp ver the fllwing hurs they shuld be advised t return Admissin fr 24 hurs and then reassessed: All patients shwing immediate, mderate r severe effects Asymptmatic individuals with high risk f expsure t txic smke (enclsed space, plastics fire r steam explsin) Asymptmatic with pre-existing lung disease, asthma r heart disease r elderly Evidence f burns, neurlgical signs, abnrmal bld gases, high CO levels, CXR r spirmetry Further Inhalatin Management The airway shuld be assessed rularly and bld gases/chest X-rays taken if indicated by the clinical cnditin f the patient. Give humidified xygen with rular suctin If delayed pulmnary edema develps, ventilate with high frequency ventilatin and PEEP 4 All patients wh have develped mderate r severe clinical effects, even if pulmnary edema did nt ccur, shuld be reviewed after discharge fr lung functin tests Dermal Management Remve any remaining cntaminated clthing, place in duble, sealed, clear bags, label and stre in a secure area away frm patients and staff Irrigate with cpius amunts f water Treat burns symptmatically, including the use f silver sulphadiazine cream (Flamazine ), if indicated Eye Management Irrigate thrughly with running water r saline fr 15 minutes Stain with flurescein and refer t an phthalmlgist if there is any uptake f the stain Page 4 f 9

5 Written by: Henrietta Harrisn and Desiree Elkabir Last updated: May 2002 References 1. Dubber ML (ed). Draft Smke Txins, Science & Txiclgy. Natinal Fcus fr Chemical Incidents and Department f Health, Heimbach DM, Waeckerle JF. Inhalatin injuries. Ann Emerg Med 1988; 17(12): Hathaway GJ, Prctr NH & Hughes JP. Prctr and Hughes Chemical Hazards f the Wrkplace, 4th ed. Van Nstrand Reinhld, New Yrk, Lee-Ching, TL. Smke Inhalatin Injury. When t suspect and hw t treat. Pstgraduate Medicine 1999; 105(2): Page 5 f 9

6 APPENDIX 1 Types f fires 1 Smuldering/nn-flaming fires: Slw thermal decmpsitin results in xidatin in nn-flaming cnditins; the prducts are rich in rganic cmpunds, and usually highly irritant t the respiratry tract. Other prducts include inrganic acids (further irritants) and CO. These fires are rarely a public health risk beynd the building, althugh they may have a strng smell and represent an envirnmental nuisance t surrunding areas Well ventilated fires: Occur when there is plenty f air, therefre cmbustin is mst efficient (e.g. the early stages f mst fires). Initially the smke and txic prducts are lw but as the fire develps carbn mnxide and carbn dixide prductin can be significant, and many inrganic materials may be released as acid gases. Ventilatin limited? cntrlled flaming fires: Occur when the air supply is restricted cmpared t the fuel available fr cmbustin. This type f fire is f mst interest in the cntext f large fires threatening the wider envirnment beynd the building f rigin, as well as the ccupants within large buildings. High cncentratins f carbn mnxide, carbn dixide, hydrgen cyanide, rganic prducts, smke and inrganic acid gases ccur Page 6 f 9

7 APPENDIX 2 Risk assessment This is difficult in the light f the current infrmatin, hwever, the fllwing may be useful in assessing ptential hazard and therefre pssible risk in cnjunctin with data n casualty and expsure lcatin: expsed within the plume ( zne 1): This is the zne f greatest risk fr txic expsure. An unknwn number f fire fficers are attending the fire: all shuld be wearing apprpriate breathing apparatus and prtective clthing as required expsed frm plume fall ut (zne2): the wind and weather dilutin factrs fr the plume will reduce the ptential txicity. Therefre a small risk f adverse health effects exists fr thse wh may be expsed frm plume fall ut. Thse with preexisting respiratry diseases such as asthma may be mre at risk cncerned abut ptential txicity (zne3): thse wh are ptentially at risk but wh have nt in fact been expsed may becme anxius and develp exacerbatin f cncurrent disease. Where there is n evidence f direct expsure, they shuld be bserved and treated fr the cncurrent disease and reassured Page 7 f 9

8 Table 1: Relatinship between fire type and hazard develpment 1 Fire type Risk Assessment Zne CO HCN HCl P 2 O 5 Iscyana te -NCO Irritants Acrlei n HF HBr & PAHs Benzene NO 2 SO 2 NH 3 Particl es Extics dixins Rubber, Emissins / / Tyres, Zne 2 Risk ± ± + ++/+ ± ± +++/ Belting Zne 3 Risk Petrl Emissins strage Zne 2 Risk + ± ++ Petrl statin Zne 3 Risk + + Plastics Emissins Factry/ Zne 2 Risk ± ± ± ± + + ± Warehuse Zne 3 Risk ± + ++ Resins Emissins and Zne 2 Risk ± ± ± ± + ± ++ + Adhesives Zne 3 Risk Paints Emissins and Zne 2 Risk ± ± + + Slvents Zne 3 Risk + + Uphlstery- Emissins Plyurethan Zne 2 Risk ± ± ± ± + + ± e Zne 3 Risk Vetatin - Emissins O 3 HARZARD LEGEND: +++ HIGH ++ MEDIUM + LOW ± POSSIBLE UNLIKELY Page 8 f 9

9 Fire type Risk Assessment Zne CO HCN HCl P 2 O 5 Iscyana te -NCO Irritants Acrlei n HF HBr & PAHs Benzene NO 2 SO 2 NH 3 Particl es Frests Zne 2 Risk + ± ± ± + Zne 3 Risk + Extics dixins O 3 Oil Emissins Refineries Zne 2 Risk ++ ± Strage Tanks Zne 3 Risk Waste Emissins Tips Zne 2 Risk ± ± ± + + ± + ++ Zne 3 Risk ++ Pesticide Emissins and especially Zne 2 Risk ± ± + ++ OP stres Zne 3 Risk Phsphrus Emissins fires Zne 2 Risk ± ± + ++ Zne 3 Risk Nte: Chlrine Nt applicable as chlrine is the main risk HAZARD LEGEND: +++ HIGH ++ MEDIUM + LOW ± POSSIBLE UNLIKELY Page 9 f 9