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Description of key information

There are several reviews and data summaries but limited primary data on the acute toxicity of furan. No primary data on acute oral or acute dermal toxicity were identified. 
Two published primary sources, that have been entered into IUCLID, report one-hour inhalation exposures to measured concentrations of furan vapour in mice and rats (Egle & Gochberg, 1979; Terrill et al., 1989). Neither is reported in sufficient detail to merit a reliability score or 1 or 2, or to qualify as a key study. The study in mice (Egle & Gochberg, 1979) is compromised by small experimental groups. The one-hour LC50 values reported for these studies are 0.12 mg/l in the mouse (Egle & Gochberg, 1979) and 3464 ppm (approx. 9.6 mg/l) in male and female rats, with a lower value of 3398 ppm (approx. 9.5 mg/l) for male rats (Terrill et al., 1989).

Key value for chemical safety assessment

Additional information

INHALATION

Animal studies

Neither of the studies entered into IUCLID has a reliability score of 1 or 2; neither is suitable as a key study (Egle & Gochberg, 1979; Terrill et al., 1989). After appropriate conversion to take account of the 1-hour exposure duration (Regulation (EC) 1272/2008, Table 3.1.1., note b), the LC50 values of these studies suggest 4-hour exposure equivalent values of 4.8 mg vapour/l (rat) and, with less reliability, 0.06 mg vapour/l (mouse).

 

A datasheet (RTECS, 2011) cites LC50 values in the rat and mouse of 2.8 mg/l/2-hour (Anon, 1968) and 3 mg/l/unspecified exposure (Anon, 1967a), respectively. The same datasheet cites lowest published inhalation lethal dose (LCLo) values in the rat: 1.5 mg/l/4-hour and mouse: 2 mg/l/2-hour (Anon, 1971; Anon, 1967b).

 

A standard text notes that furan is “highly toxic by inhalation in animals” and that ”dogs and rabbits collapsed and died after two inhalations from saturated cotton wool” (Browning, 1965). Effects reported include increased respiration rate, reduced blood pressure, convulsive movements, anaesthesia, death from asphyxiation and effects to the central nervous system.

 

Human toxicity

A published review describing potential human toxicity effects (Pohanish, 2008), notes that inhalation of the vapour can cause depression of the central nervous system, headache, dizziness, shortness of breath, unconsciousness and suffocation. “Higher” exposures can cause pulmonary oedema, sometimes delayed for several hours, that can be lethal. Such acute inhalation exposure may cause both reversible and irreversible changes.

 

An abstract notes that occupational exposure to “furan resin sand” (no further details on composition) was associated with “acute restrictiveness” identified in lung function tests following a work shift (39 exposed moulders and core makers and 27 unexposed local controls were examined). It is of course probable that those exposed during this shift had prior repeated exposure, but no further relevant details are given in the abstract (Ahmanet al.1991).

 

ORAL

Animal studies

A datasheet (RTECS, 2011) cites a rather old lowest published oral lethal dose (LDLo) of 234 mg/kg bw in the dog and the rabbit (Anon, 1926). The brief description of the toxic effects, including changes to salivary glands, nausea or vomiting, and haemorrhage (not further described), suggest the presence of local effects. Local effects are also described following oral administration to an unspecified laboratory species with corrosion of the oral mucosa, bloody saliva and watery discharge from the nose (Browning, 1965).

 

Human toxicity

A review describing potential human toxicity notes that ingestion is “associated with high toxicity” (Pohanish, 2008). No further details are given.

 

DERMAL

Human toxicity

This same review also notes that human dermal absorption is “associated with high toxicity”; no further details are given (Pohanish, 2008).

REFERENCES

Ahman M; Alexandersson R; Ekholm U; Bergström B; Dalqvist M; Ulfvarson U. (1991). Impeded lung function in moulders and coremakers handling furan resin sand. Int Arch Occup Environ Health 63, 175-180 (as cited in HSDB, 2011).

 

Anon (1926). Journal of Pharmacology and Experimental Therapeutics 26, 281 (as cited in RTECS, 2011).

 

Anon (1967a). Toksikologiya Novykh Promyshlennykh Khimicheskikh Veshchestv [Toxicology of New Industrial Chemical Substances] 9, 3 (as cited in RTECS, 2011).

 

Anon (1967b). Toksikologiya Novykh Promyshlennykh Khimicheskikh Veshchestv [Toxicology of New Industrial Chemical Substances] 9, 106 (as cited in RTECS, 2011).

 

Anon (1968). Toksikologiya Novykh Promyshlennykh Khimicheskikh Veshchestv [Toxicology of New Industrial Chemical Substances] 10, 35 (as cited in RTECS, 2011).

 

Anon (1971). Toksikologiya Novykh Promyshlennykh Khimicheskikh Veshchestv [Toxicology of New Industrial Chemical Substances] 12, 44 (as cited in RTECS, 2011).

 

Browning (1965). Toxicity and Metabolism of Industrial Solvents.: American Elsevier, p699 (as cited in HSDB, 2011).

 

Egle JL; Gochberg BJ (1979).Respiratory retention and acute toxicity of furan. American Industrial Hygiene Association Journal. 40 (4), 310-314.

 

HSDB (2011). Hazardous Substances Data Bank. Databank Number 89, last revised 16 June 2011.http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~lMMQU6:1

 

Pohanish, R.P (ed) (2008). Sittig’s Handbook of Toxic and Hazardous Chemical Carcinogens, 4th Edition Volume 1: A-H; p1194-1196.

 

RTECS (2011). Registry of Toxic Effects of Chemical Substances. Canadian Centre for Occupational Health and Safety. Datasheet LT8524000, last updated October 2011.

 

Terrill JB; Van Horn WE; Robinson D; Thomas DL (1989). Acute inhalation toxicity of furan, 2-methyl furan, furfuryl alcohol, and furfuryl in the rat. American Industrial Hygiene Association Journal 50, A359-A361.

Justification for classification or non-classification

Furan is officially classified Acute Tox 4, H332 & H302: harmful if inhaled; harmful if swallowed (Regulation (EC) 1272/2008).

 

The more reliable of the two inhalation studies cited above (Terrill et al., 1989) gives a 4-hour equivalent LC50 value in the in rat of 4.8 mg vapour/l; this value would suggest the classification for vapour inhalation Category 3.

 

It is unclear from the data reported here how the current classification for acute oral and inhalation toxicity might have been derived. However, had the result of Terrill et al. been considered as ppm gas or as ppm vapour near to the gaseous phase (Regulation (EC) 1272/2008, Table 3.1.1., note c), and without adjustment for exposure duration (ibid.note b), then Category 4 would be indicated.