Methyl methacrylate

CAS number: 80–62–6

NIOSH REL: 100 ppm (410 mg/m³) TWA

Current OSHA PEL: 100 ppm (410 mg/m³) TWA

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 100 ppm (410 mg/m³) TWA

Description of substance: Colorless liquid with an acrid, fruity odor.

LEL: . . . 1.7% (10% LEL, 1,700 ppm)

Original (SCP) IDLH: 4,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by ACGIH [1971] that 4,400 ppm was fatal to rats and rabbits in 8 hours [Deichmann 1941]. Also, Patty [1963] cited an approximate rat LC₅₀ of 3,750 ppm [Deichmann 1941; Spealman et al. 1945].

Short-term exposure guidelines: None developed

ACUTE TOXICITY DATA:

Lethal concentration data:

Species	Reference	LC50 (ppm)	LCLo (ppm)	Time	Adjusted 0.5-hr LC (CF)	Derived value
Rat	Blagodatin et al. 1976	18,750	-----	4 hr	37,500 ppm (2.0)	3,750 ppm
Mouse	Blagodatin et al. 1976	4,447	-----	2 hr	7,115 ppm (1.6)	712 ppm
Rat	Deichmann 1941	-----	4,400	8 hr	11,000 ppm (2.5)	1,100 ppm
Rabbit	Deichmann 1941	-----	4,400	8 hr	11,000 ppm (2.5)	1,100 ppm
Rabbit	Deichmann 1941	-----	4,207	4.5 hr	8,751 ppm (2.08)	875 ppm
G. pig	Deichmann 1941	-----	4,567	5 hr	9,819 ppm (2.15)	982 ppm
Rat	Deichmann 1941	3,750	-----	?	?	?
Mammal	Gig Sanit 1986	4,808	-----	?	?	?

Human data: Workers have experienced irritation, but tolerated 200 ppm without complaint [Spealman et al. 1945]. It has also been reported that 2,300 ppm was intolerable [Coleman 1963].

Revised IDLH: 1,000 ppm Basis for revised IDLH: The revised IDLH for methyl methacrylate is 1,000 ppm based on acute inhalation toxicity data in humans [Coleman 1963] and animals [Blagodatin et al. 1976; Deichmann 1941].

REFERENCES:

1. ACGIH [1971]. Methyl methacrylate. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, p. 168.

2. Blagodatin VM, Smiznova ES, et al. [1976]. Substantiation of the maximum permissible concentration of methacrylic acid methyl ether in the air of the working zone. Gig Tr Prof Zabol 20(6):5-8 (in Russian).

3. Coleman AL [1963]. Letter to the TLV Committee from State of Connecticut, Labor Department, Occupational Health Section (March 15, 1963).

4. Deichmann W [1941]. Toxicity of methyl, ethyl, and n-butyl methacrylate. J Ind Hyg Toxicol 23:343-351.

5. Gig Sanit [1986]; 51(5):61 (in Russian).

6. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1880.

7. Spealman CR, Main RJ, Haag HB, Larson PS [1945]. Monomeric methyl methacrylate. Am J Ind Med 14(4):292-298.