# NIOSH Pocket Guide to Chemical Hazards
Methyl ethyl ketone peroxide | CAS 1338-23-4
C8H16O4 | RTECS EL9450000
Synonyms & Trade Names 2-Butanone peroxide, Ethyl methyl ketone peroxide, MEKP, MEK peroxide, Methyl ethyl ketone hydroperoxide | DOT ID & Guide 2550 147
Exposure Limits | NIOSH REL: C 0.2 ppm (1.5 mg/m3)
OSHA PEL†: none
IDLH N.D. | Conversion 1 ppm = 7.21 mg/m3
Physical Description Colorless liquid with a characteristic odor. [Note: Explosive decomposition occurs at 230°F.]
MW: 176.2 | BP: 244°F (Decomposes) | FRZ: ? | Sol: Soluble
VP: ? | IP: ? |  | Sp.Gr(59°F): 1.12
Fl.P(oc): 125-200°F (60% MEKP) | UEL: ? | LEL: ? |
Combustible Liquid
Incompatibilities & Reactivities Organic materials, heat, flames, sunlight, trace contaminants [Note: A strong oxidizing agent. Pure MEKP is shock sensitive. Commercial product is diluted with 40% dimethyl phthalate, cyclohexane peroxide, or diallyl phthalate to reduce sensitivity to shock.]
Measurement Methods NIOSH 3508; OSHA 77
Personal Protection & Sanitation Skin: Prevent skin contact Eyes: Prevent eye contact Wash skin: When contaminated Remove: When wet or contaminated Change: No recommendation Provide: Eyewash, Quick drench | First Aid (See procedures) Eye: Irrigate immediately Skin: Water wash immediately Breathing: Respiratory support Swallow: Medical attention immediately
Respirator Recommendations To be added later
Exposure Routes inhalation, ingestion, skin and/or eye contact
Symptoms Irritation eyes, skin, nose, throat; cough, dyspnea (breathing difficulty), pulmonary edema; blurred vision; blisters, scars skin; abdominal pain, vomiting, diarrhea; dermatitis; in animals: liver, kidney damage
Target Organs Eyes, skin, respiratory system, liver, kidneys
See also: INTRODUCTION