From the MSDS:
"Aspiration into lungs can produce severe lung damage and is a medical emergency."
"Higher concentrations may cause central nervous system depression and unconsciousness."
"Chronic exposure may cause central nervous system effects."
"For emergencies or instances where the exposure levels are not known, use a full-facepiece positive-pressure, air-supplied respirator. WARNING: Air purifying respirators do not protect workers in oxygen-deficient atmospheres."
And you guys are spraying this stuff through your airbrushes????!!!!!!!
NO NO NO NO.

Many things, correct and incorrect have been stated on this list about MEK. Lets not go by memory (which may be affected by MEK) and instead go to an authoritative source, a Material Safety Data Sheet. There are various sources available on the web, an easy one is:http://www.jtbaker.com/msds/m4628.htm Relevant portions include: DANGER! EXTREMELY FLAMMABLE LIQUID AND VAPOR. VAPOR MAY CAUSE FLASH FIRE. HARMFUL OR FATAL IF SWALLOWED. HARMFUL IF INHALED OR ABSORBED THROUGH SKIN. AFFECTS CENTRAL NERVOUS SYSTEM. CAUSES IRRITATION TO SKIN, EYES AND RESPIRATORY TRACT.
Health Rating: 2 - Moderate
Flammability Rating: 4 - Extreme (Flammable)
Reactivity Rating: 2 - Moderate
Contact Rating: 2 - Moderate
Lab Protective Equip: GOGGLES; LAB COAT; VENT HOOD; PROPER GLOVES; CLASS B EXTINGUISHER
Potential Health Effects
Inhalation: Causes irritation to the nose and throat. Concentrations above the TLV may cause headache, dizziness, nausea, shortness of breath, and vomiting. Higher concentrations may cause central nervous system depression and unconsciousness. Skin Contact: Causes irritation to skin. Symptoms include redness, itching, and pain. May be absorbed through the skin with possible systemic effects. Eye Contact: Vapors are irritating to the eyes. Splashes can produce painful irritation and eye damage. Farther down one will find that MEK is not now recognized nor anticipated to be a carcinogen. However, it has shown reproductive teratogenic effects in laboratory animals so keep an eye on you kids.... Bottom line - avoid if possible, protect yourself if you feel you must use it.

1) Custer's opinion that most teratogens affect only women is completely wrong.
2) Where did he get the statistic that 10 years is the required time to "metabolize anything in the body away"? Does the word mutation mean anything to him?
3) The "eggs" in the ovaries begin as oocytes in the primordial follicles, of which approximately 400,000 are present at birth, i.e, well before puberty. Oocyte maturation is then arrested at the time of birth, until follicular maturation prior to ovulation.
4) The suggestion that males have a protective advantage because they continuously produce sperm is wrong and dangerous. If the latest "crop" of sperm is affected by a teratogen (including alcohol) and that sperm is used to fertilize the egg, the embryo may demonstrate defects related to the damaged sperm. Many defects are due to teratogenic effects on the embryo and fetus and occur after conception, such as those due to thalidomide or radiation. Different teratogens affect the fetus at different stages of development; some that may have devastating effects in the first trimester may have no effect in the third trimester. This is dependent on the particular teratogen, which organ system it affects, how it affects that organ system and when that organ system is undergoing development.
5) What is Custer's definition of small amounts of exposure over time? What does he consider small and how does he measure this? How certain is he that these small amounts of exposure will have no effect and on what evidence does he base this? Fred, If you want detailed accurate information concerning teratogenesis and your own possible risks, get it from a physician who practices reproductive medicine. If you are concerned about possible hereditary conditions, ask the reproductive medicine physician to refer you to a geneticist. This sort of information should be as specific as possible to the individual(s) involved, and detailed exposure, medical and family histories are essential. An opinion from a lay person is dangerous...