Isophorone is a chemical with the formula C₉H₁₄O. It is a clear liquid with a peppermint-like smell. It evaporates faster than water but slower than charcoal starter or paint thinner and does not mix completely with water. Although it is man-made, it can naturally occur in cranberries.
What is Isopherone used for?
Isophorone is primarily used as a solvent in:
Coating systems for metal cans, metal paints, and nitrocellulose finishes.
Printing inks for plastics.
Herbicide and pesticide formulations.
Adhesives for plastics, polyvinyl chloride (PVC), and polystyrene.
It is also an intermediate chemical in making 3,5-xylenol, 3,3,5-trimethylcyclohexanol, and plant growth retardants.
Isophorone is primarily used as a solvent in coating systems for metal cans, metal paints, and nitrocellulose finishes.
In the Environment
Isophorone is released into the air from products like inks and paints.
In the air, it breaks down quickly, with half disappearing in less than five hours.
It can enter water from industrial sources, breaking down over days to about a month by bacteria.
In soil, isophorone may break down, evaporate into the air, or filter into groundwater, but limited data is available.
Isophorone does not accumulate in the food chain.
Sources & Routes of Exposure
Source of Exposure
Air: Major sources include the printing and metal coating industries. Coal-fired power plants may also release isophorone.
Workplace: People working with inks, paints, lacquers, and adhesives are more likely to be exposed.
Water: Isophorone has been found in low concentrations in drinking water.
Routes of Exposure
Breathing air containing isophorone.
Drinking contaminated water.
Eating food with isophorone.
Occupational exposure in industries using isophorone.
Health Effects
Acute Effects
In humans: Skin, eye, nose, and throat irritation; headaches; and dizziness.
In animals: High levels cause inactivity and coma. Tests show moderate toxicity through inhalation or ingestion.
Chronic Effects
Long-term exposure may cause dizziness, fatigue, and depression in humans.
In animals: Central nervous system effects, including narcosis, staggering, depression, ataxia, lethargy, prostration, and coma.
Safe exposure limits:
Reference Dose (RfD): 0.2 mg/kg/day based on studies in dogs.
Provisional Reference Concentration (RfC): 0.012 mg/m³ based on rat studies.
California EPA Reference Exposure Level (REL): 2 mg/m³ for long-term exposure based on developmental effects in rats.
Reproductive/Developmental Effects
No human studies are available.
Limited animal studies suggest potential birth defects and growth retardation during pregnancy with inhalation exposure.
Cancer Risk
No human studies exist.
Animal studies show increased kidney and reproductive gland tumors in male rats. However, these findings may not be relevant to humans.
EPA classifies isophorone as a possible human carcinogen (Group C).
Safety
First Aid Measures
Inhalation: Move to fresh air. If not breathing, provide artificial respiration and consult a doctor.
Skin Contact: Wash thoroughly with soap and water. Consult a doctor.
Eye Contact: Rinse eyes with water for at least 15 minutes. Consult a doctor.
Ingestion: Rinse mouth with water. Do not give anything by mouth to an unconscious person. Consult a doctor.
Inhalation: Move to fresh air. If not breathing, provide artificial respiration and consult a doctor.
Skin Contact: Wash thoroughly with soap and water. Consult a doctor.
Eye Contact: Rinse eyes with water for at least 15 minutes. Consult a doctor.
Ingestion: Rinse mouth with water. Do not give anything by mouth to an unconscious person. Consult a doctor.
Exposure Controls & Personal Protection
Engineering Controls
Practice good hygiene and industrial safety practices. Wash hands during breaks and after work.
Personal Protective Equipment (PPE)
Eye/Face Protection: Use a face shield and safety glasses that meet government standards (NIOSH or EN 166).
Skin Protection: Wear gloves, inspect them before use, and dispose of them safely after use. Wash hands thoroughly. Gloves must meet EU standards EN 374.
Body Protection: Wear a chemical-resistant suit appropriate to the substance concentration and amount.
Respiratory Protection: Use a full-face respirator with multi-purpose cartridges (US NIOSH or EU EN 14387) or a supplied-air respirator if necessary. Ensure respirators meet government standards.
Regulation
United States
OSHA: The Occupational Safety & Health Administration has set the following Permissible Exposure Limits (PEL) for isophorone:
General Industry: 29 CFR 1910.1000 Table Z-1 - 25 ppm, 140 mg/m3 TWA
Construction Industry: 29 CFR 1926.55 Appendix A - 25 ppm, 140 mg/m3 TWA
ACGIH: The American Conference of Governmental Industrial Hygienists has set a Threshold Limit Value (TLV) for isophorone of 5 ppm, 28 mg/m3 Ceiling; Appendix A3 - Confirmed Animal Carcinogen with Unknown Relevance to Humans
NIOSH: The National Institute for Occupational Safety and Health has set a Recommended Exposure Limit (REL) for isophorone of 4 ppm, 23 mg/m3 TWA
Australia
Safe Work Australia: Safe Work Australia has set a time weighted average concentration of 5 ppm, 28 mg/m3 Ceiling for isophorone for a 40-hour work week. It also has an advisory carcinogen category of carc.2 which is a suspected human carcinogen.
As scientists who evolve with technology we treat innovation as a way of life, a life we dedicate to improvement and advancement of Safety, Health and Environment.
