1,3-Dichloro-5,5-dimethylhydantoin

CAS number: 118–52–5

NIOSH REL: 0.2 mg/m³ TWA, 0.4 mg/m³ STEL

Current OSHA PEL: 0.2 mg/m³ TWA

1989 OSHA PEL: 0.2 mg/m³ TWA, 0.4 mg/m³ STEL

1993-1994 ACGIH TLV: 0.2 mg/m³ TWA, 0.4 mg/m³ STEL

Description of Substance: White powder with a chlorine-like odor.

LEL:. . Unknown

Original (SCP) IDLH*: Unknown [*Note: "Effective" IDLH = 5 mg/m³ -- see discussion below.]

Basis for original (SCP) IDLH: Very little data are available on which to base an IDLH for 1,3-dichloro-5,5-dimethylhydantoin. For this draft technical standard, therefore, the respirators have been selected on the basis of the assigned protection factor afforded by each device up to 25 × the OSHA PEL of 0.2 mg/m³ (i.e., 5 mg/m³); only the "most protective" respirators are permitted for use in concentrations exceeding 5 mg/m³.

Short-term exposure guidelines: None developed

ACUTE TOXICITY DATA

Lethal concentration data:

Species	Reference	LC50	LCLo	Time	Adjusted 0.5-hr LC (CF)	Derived value
Rat	Glyco 1981	-----	20,000 mg/m3	1 hr	25,000 mg/m3 (1.25)	2,500 mg/m3

Lethal dose data:

Species	Reference	Route	LD50 (mg/kg)	LDLo (mg/kg)	Adjusted LD	Derived value
Rat Rabbit G. pig	Kay 1961/1962 Korolev et al. 1982 Korolev et al. 1982	oral oral oral	542 1,520 1,350	----- ----- -----	3,794 mg/m3 10,640 mg/m3 9,450 mg/m3	379 mg/m3 1,064 mg/m3 945 mg/m3

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

Revised IDLH: 5 mg/m3 Basis for revised IDLH: Based on health considerations and acute oral toxicity data in animals [Kay 1961/62; Korolev et al. 1982], a value of about 500 mg/m3 would have been appropriate for 1,3-dichloro-5,5-dimethylhydantoin. However, the revised IDLH for 1,3-dichloro-5,5-dimethylhydantoin is 5 mg/m3 based on being 25 times the NIOSH REL and OSHA PEL of 0.2 mg/m3 (25 is an assigned protection factor for respirators and was used during the Standards Completion Program for deciding when the "most protective" respirators should be used for 1,3-dichloro-5,5-dimethylhydantoin).

REFERENCES:

1. Chrostek WJ, Cromer JW [1975]. Health hazard evaluation report HHE 73-160-206, Glyco Chemicals, Inc., Williamsport, PA. Cincinnati, OH: National Institute for Occupational Safety and Health, Division of Surveillance, Hazard Evaluations, and Field Studies.

2. Glyco Chemicals [1981]. 1,3-Dichloro-5,5-dimethyl-2,4-imidazolidinedione. In: TSCA 8(e) Submission to the U.S. Environmental Protection Agency (8EHQ-0281-0382). Williamsport,PA: Glyco® Chemicals, Inc.

3. Kay JH [1961/1962]. Unpublished technical reports. Northbrook, IL: Industrial Bio-Test Laboratories. (August 28, 1961; May 1, 1962).

4. Korolev AA, Vasilenko VE, et al. [1982]. Hygienic standard of dichloantine and the product of its transforation with dimethylhydantoin in water. Gig Sanit 47(6):76-78 (in Russian).