Methylene bisphenyl isocyanate (MDI)

IDLH Documentation
CAS number: 101­68­8

NIOSH REL: 0.05 mg/m3 (0.005 ppm) TWA,

0.2 mg/m3 (0.020 ppm) 10­minute CEILING

Current OSHA PEL: 0.2 mg/m3 (0.02 ppm) CEILING

1989 OSHA PEL: Same as current PEL

1993­1994 ACGIH TLV: 0.051 mg/m3 (0.005 ppm) TWA

Description of substance: White to light­yellow, odorless flakes.

LEL: . . Unknown

Original (SCP) IDLH: 100 mg/m3

Basis for original (SCP) IDLH: The chosen IDLH is based on an analogy with toluene diisocyanate, which has an IDLH of 10 ppm. [Note: A concentration of 10 ppm methylene bisphenyl isocyanate is equivalent to about 100 mg/m3.]

Short­term exposure guidelines: None developed

ACUTE TOXICITY DATA:

Lethal concentration data:

Species
Reference
LC50
LCLo
Time
Adjusted 0.5-hr LC (CF)
Derived value
RatBunge et al. 1977
369 mg/m3
-----
4 hr
738 mg/m3 (2.0)
74 mg/m3
RatBunge et al. 1977
380 mg/m3
-----
4 hr
760 mg/m3 (2.0)
76 mg/m3
RatWoolrich 1982
178 mg/m3
-----
?
?
?

Lethal dose data:

Species
Reference
Route
LD50 (mg/kg)
LDLo (mg/kg)
Adjusted LD
Derived value
MouseIzmerov et al. 1982
oral
2,200
-----
15,400 mg/m3
1,540 mg/m3
RatWoolrich 1982
oral
-----
31,690
221,830 mg/m3
22,183 mg/m3

Human data: None relevant for use in determining the revised IDLH.


Revised IDLH: 75 mg/m3

Basis for revised IDLH: The revised IDLH for methylene bisphenyl isocyanate is 75 mg/m3 based on acute inhalation toxicity data in animals [Bunge et al. 1977].

REFERENCES:

1. Bunge W, Ehrlicher H, Kimmerle G [1977]. Medical aspects of work with surface coating systems using the spraying technique. Zentralbl Arbeitsmed Arbeitsschutz Prophylaxe 4(spec. ed.):1­46 (in German). [From ACGIH [1991]. Methylene bisphenyl isocyanate. In: Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 978­980.]

2. Izmerov NF, Sanotsky IV, Sidorov KK [1982]. Toxicometric parameters of industrial toxic chemicals under single exposure. Moscow, Russia: Centre of International Projects, GKNT, p. 63.

3. Woolrich PF [1982]. Industrial hygiene and medical control of TDI, MDI and PMPPI. Am Ind Hyg Assoc J 43(2):89­97.
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