Evaluation of hazardous substances concentrations during fire service operations

Guideline 10/01 was updated taking into account the international Acute Exposure Guideline Levels AEGL). This guideline is available in German and English.

The current edition of guideline 10/01 was published in autumn 2005. Under http://www.epa.gov/oppt/aegl/pubs/chemlist.htmcurrent AEGL values are available for download (in English). Also available are explanatory statements for the individual substances. In appendix 1 the latest ETW-4 values were inserted in autumn of 2014. Because of actual discussion about different levels for shorter incidents we added additional values for response-times up to 1h (ETW-1).

From the list of leading flue gases, formaldehyde, which was also included in the underlying research project, has been deleted, because it "only" arises as a reaction product. This leaves the following leading flue gas substances (see also vfdb guideline 10/03): CO carbon monoxide, HCN hydrogen cyanide (“hydrocyanic acid“) and HCl hydrogen chloride ("hydrochloric acid").

To evaluate the hazards from inhaling toxic gases and vapours, so-called mission tolerance values (ETW) tailored to the requirements of the fire brigades were determined. The ETW have been defined toxicologically to take care that these values do not impair the health and operability of mission teams without respiratory during an approximate four hour mission and during the time afterwards.

Since the end of 1998 work on similarly defined values has been carried out internationally under the leadership of the USA. These AEGL values (Acute Exposure Guideline Levels) will replace the ERPG (Emergency Response Planning Guidelines) values in the years to come. Since the AEGL-2 values for 4 hours correspond to the ETW in their definition, the ETW will be replaced by the AEGL-2 values as soon as these are available. This vfdb guideline has therefore been revised taking into account the currently published AEGL-2 values. During the first step AEGL-2 4h values were accepted for substances relevant to fire brigades irrespective of whether they had been finalised or not. Since 2007 changes in AEGL-2, 4h values are only accepted as ETW if they have a final status. Further changes can be expected in the future, because currently some additional substances from the ETW list do not yet have a final AEGL status.

During 2008 several newly published finalised AEGL-2 (4h) values were reviewed for acceptance by ETW criteria. In accordance with the ETW criteria the ETW of hydrogen chloride was then changed from 5.4 to 11 ppm (new final AEGL-2 (4h) value).

For 3 further substances new final AEGL-2 (4h) values were published during 2010. These were agreed by department 10 during the autumn meeting 2010 for acceptance as new ETW: Fluorine from 2 to 2.3 ppm, carbon disulphide from 10 to 100 ppm and sulphur dioxide from 1 to 0.75 ppm. In 2013 changes for a total of 5 substances were introduced during the spring meeting and in the summer: Chlorobenzene from 100 to 150 ppm, chloroform from 44 to 40 ppm, vinyl chloride from 100 to 820 ppm, hexane from 200 to 2900 ppm and nitric acid from 3 to 6 ppm. In particular the rise for hexane was discussed intensively. For all substances the limited deployment period for fire brigades (as opposed to e.g. threshold limit values for 8h daily, for an entire working life) and the kind of potential damage are examined scientifically. The reason for these - and the other values - are stated in the original AEGL document (see above for link). Department 10 therefore retains the acceptance of the established AEGL values as basis for the ETW list. For 2 substances from the list faulty CAS numbers were corrected. Many thanks for pointing them out.

Beside 4 new ETW in autumn 2014 (Acrylonitrile 20->0,48 ppm, Carbon tetrachloride 39 -> 7.6 ppm, Epichlorohydrin 16 ->14 ppm and Toluene 94 -> 310 ppm) we added because of current discussions additional guidance values for fire brigade or other hazmat deployment with a planned maximum exposure up to 1h. Guideline 10/01 will be updated till spring 2015 and published afterwards. Detailed reasons for the addition of 1h guidance values are given in the GFPA-paper (vfdb-Zeitschrift) 1/2014 (german only).

The user of the guideline is responsible for checking whether the document is applicable for his specific case and that he has the most recent version. Any liability of vfdb and all those involved in the preparation of the document is excluded.

ETW were defined for substances inasmuch as these are relevant as gases or vapours during missions and can be immediately detected by simple means.