Establish the substance identity
MIBK has CAS number 108-10-1 and is also called 4-methyl-2-pentanone. MEK has a different identity and properties. Similar abbreviations do not justify reusing limits, gloves or procedures. Check full names and commercial-mixture composition, including products introduced in small quantities to adjust a formulation or to clean equipment after the main process.
Coatings and extraction
INRS lists uses in adhesives, inks, paints and varnishes, pharmaceutical extraction and metal separation. Extraction assessment should examine transfers, sampling and removal of phases or residues; coatings assessment includes application and drying. An unchanged purchased quantity does not imply unchanged exposure if open surface area or the proximity of workers to emission sources changes.
Record the relevant hazards
The INRS sheet includes eye irritation, harm by inhalation, drowsiness or dizziness and suspected carcinogenicity. The latter should not be omitted when comparing alternatives. Hazard classification does not calculate an individual disease probability. Prevention decisions also need concentration, duration and actual conditions, rather than relying only on the absence of immediate irritation or other noticeable effects.
Airborne exposure and contact
Agree occupational hygiene sampling that identifies MIBK within the mixture and represents relevant tasks. Observe hands, clothing and surfaces too, because repeated contact can damage skin. Results should distinguish enclosed processing from open operations. A general detector or production figure does not replace a description of personal exposure and the conditions under which the measurements were collected.
Compatibility and solvent recovery
MIBK is highly flammable. INRS describes incompatibilities, effects on certain plastics and circumstances in which oxidation can form peroxides. Recovery or concentration operations need specific technical procedures; they should not be improvised with aged solvent or material of unknown composition. Review storage, waste and process safety using supplier information and competent technical advice before such work proceeds.
Compare substitutions without shifting risk
Assess an alternative’s hazards, process behaviour and resulting exposure. Replacing MIBK with another solvent does not itself demonstrate improvement. If the replacement needs a higher temperature or more manual application, assess those conditions. Record why it was chosen, which controls it needs and how performance will be verified after implementation under real working conditions.
Maintain a reviewable record
Keep composition, uses, measurements and the basis for control selection. If a previously enclosed stage becomes manual, review exposure even if the product remains unchanged. Check current values and requirements for the country of work, avoiding presentation of a historical table as a universal criterion. Professional health surveillance complements exposure reduction but cannot replace effective control at the process.
