Acetylene tetrabromide

CAS number . . . . . . . . . . . 79-27-6
NIOSH REL. . . . . . . . . . . . The 1989 OSHA PEL may not be protective to
                                 workers.
Current OSHA PEL . . . . . . . . 1 ppm (14 mg/m3) TWA
1989 OSHA PEL. . . . . . . . . . Same as current PEL
1993-1994 ACGIH TLV. . . . . . . 1 ppm (14 mg/m3) TWA
Description of substance . . . . Pale-yellow liquid with a pungent odor
                                 similar to camphor or iodoform.
LEL. . . . . . . . . . . . . . . Noncombustible Liquid
Original (SCP) IDLH. . . . . . . 10 ppm
Basis for original (SCP) IDLH. . Van Haaften [1969] reported that a chemist
                                 who had been exposed to 1 to 2 ppm for 7.5
                                 hours, with only a single 10-minute
                                 exposure at 16 ppm, almost died from liver
                                 damage.  Because the TLV is 1 ppm [ACGIH
                                 1976], it is assumed that exposure to 1 to
                                 2 ppm would be a safe concentration for the
                                 7.5 hours the worker was exposed.  Therefore,
                                 the injury must have been produced by the
                                 10-minute exposure to 16 ppm, and the IDLH
                                 would be expected to fall between 2 ppm and
                                 15 ppm.  For this draft technical standard,
                                 an IDLH of 10 ppm is assumed.  This is an
                                 extremely toxic substance.
Short-term exposure guidelines . None developed

ACUTE TOXICITY DATA

Lethal concentration data:

                                                       Adjusted               
                             LC50    LCLo               0.5-hr         Derived
Species     Reference       (ppm)   (ppm)    Time       LC (CF)         Value
______________________________________________________________________________
Rat     Izmerov et al. 1982    38   -----    4 hr      76 ppm (2.0)    7.6 ppm

Lethal dose data:
                                  

                                                                              
                                      LD50     LDLo                   Derived
Species     Reference         Route  (mg/kg)  (mg/kg)   Adjusted LD    Value
_____________________________________________________________________________
G. pig   Gray 1950            oral     400     -----      195 ppm      20 ppm
Rabbit   Gray 1950            oral     400     -----      195 ppm      20 ppm
Mouse    Izmerov et al.1982   oral     269     -----      131 ppm      13 ppm
Rat      Paustovskaya et al.  oral   1,200     -----      585 ppm      59 ppm
         1967

                                  
Human data . . . . . . . . . . . Severe acute intoxication was reported in a
                                 chemist after exposure to 16 ppm for about 10
                                 minutes and to 1 to 2 ppm for most of the day
                                 [Van Haaften 1969].

Revised IDLH: 8 ppm
Basis for revised IDLH: The revised IDLH for acetylene tetrabromide is 8 ppm based on acute inhalation toxicity data in animals [Izmerov et al. 1982].

REFERENCES:

1. ACGIH [1976]. TLVs, Threshold limit values for chemical substances and physical agents in the workroom environment with intended changes for 1976. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, p. 9.
2. Gray MG [1950]. Effect of exposure to the vapors of tetrabromoethane (acetylene tetrabromide). AMA Arch Ind Hyg Occup Med 2:407-419.
3. Izmerov NF, Sanotsky IV, Sidorov KK [1982]. Toxicometric parameters of industrial toxic chemicals under single exposure. Moscow, Russia: Centre of International Projects, GKNT, p. 107.
4. Paustovskaya VV, et al. [1967]. Effect of tetrabromomethane on the parenchymatous organs in experimental conditions. Med Pr 3:80-83 (in Polish).
5. Van Haaften AB [1969]. Acute tetrabromoethane (acetylene tetrabromide) intoxication in man. Am Ind Hyg Assoc J 30:251-256.