P. UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460 '44 pqcl 

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OFFICE OF PESTICIDES ANDTOXIC SUBSTANCES
MEMORANDUM SUBJECT : EPCRA Section 313 Delisting Petition : Absorption

Review for Methyl Ethyl Ketone (MEK ) FROM : Leonard C . Keifer, Ph .D ., FAIC

Chemis t Metabolism and Carcinogenesis Section Health Effects Branch Health and Environmental Review Division (7403) TO : Lorraine Randecker

Hazard Integrator Analysis and Information Management Branch Chemical Screening and Ris k Assessment Division (7402) THRU : David Y . Lai, Ph .D .

Acting Section Chief Metabolism and Carcinogenesis Sectio n Health Effects Branch Health and Environmental Review Division (7403)

I . INTRODUCTION A petition was filed for delisting MEK from Section 313 TRI reporting . At the request of the MEK work group a summary of the absorption of MEK from the lung and GI tract and through the skin is provided . The information presented is, for the most part, taken from the ATSDR toxicological profile for MEK (ATSDR, 1992) . II . CONCLUSIONS MEK is well absorbed from the lung, GI tract, and skin . Pulmonary uptake in humans ranged from 41% to 56% . Case reports in humans and/or studies in rats demonstrate that MEK is absorbed from the GI tract and the skin ; however, the available informatir- T-T=C~ nr~t- qllfficient to determine the percent of the dose absorbed
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III . BASES FOR CONCLUSIONS A . Lung : 2-Butanone (MEKI is well absorbed during inhalation exposure . Pulmonary uptake in humans ranged from 41% to 56% of the inspired quantity (Liira et al . 1988a, 1988b, 1990 [all as cited in ATSDR, 1992]) . Exercise increased the pulmonary uptake because of the greater ventilatory rate (Liira et al
. 1988b (as cited in ATSDR, 19921) . B . GI Tract : A woman who had metabolic acidosis after having accidentally ingested 2-butanone [MEKI stored in a rum bottle had a blood concentration of 95 mg/100 mL (13 .2 mM) (Kopelman and Kalfayan 1983 (as cited in ATSDR, 1992]) . Oral administration (gavage) of 1,690 mg 2-butanone [MEKI/kg in rats resulted in a plasma concentration of 94 mg/100 mL at 4 hours (Dietz and Traiger 1979 [as cited in ATSDR, 1992]) . Within 18 hours, the plasma concentration decreased to 6 .2 mg/100 mL (Dietz and Traiger 1979 [as cited in ATSDR, 1992]) . These studies demonstrate that MEK is absorbed from the GI tract ; however, the available information was not sufficient to determine the percent of the dose absorbed
. C . Skin : Measurable (2 .54 to 13 btg/L) quantities of methyl ethyl ketone appeared in expired air of adult humans 3 min following dermal exposure to 100 mL of methyl ethyl ketone [MEKI applied to 91 .5 CM2 Of skin (Wurster ; J Pharm Sci 54 : 554 ; 1965 [as cited in HSDB, 1997]) . Data were not available to determine the percentage of the applied dose that was absorbed .

REFERENCES ATSDR . 1992 . Toxicological Profile for 2-Butanone (MEK] . U .S . Department of Health & Human Services . Public Health Section . Agency for Toxic Substances and Disease Registry, Division of Toxicology, Mail Stop E-29, 1600 Clifton Road, N .E ., Atlanta, GA 30333 . HSDB . 1997 . Hazardous Substances Data Base Record for Methyl Ethyl Ketone .

CC : Fred Metz (7406) Daniel Bushman (7408)

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