Three names are not interchangeable
MEK means methyl ethyl ketone or butanone. MEKP is methyl ethyl ketone peroxide, with different hazards and uses; MIBK is another ketone. Check CAS number 78-93-3 and product information before accepting an abbreviation on a purchasing order or procedure. An identification error can affect storage, compatibility decisions and the arrangements used when an incident occurs.
Tasks where it may appear
INRS lists solvent uses in adhesives, paints, inks and coatings, as well as degreasing and other processes. Exposure may concentrate in preparation, application and manual cleaning even where the main process is enclosed. Include soaked cloths and tools, and workers cleaning equipment after the production shift rather than only operators present during the principal manufacturing stage.
Effects to prevent
The ICSC describes eye and respiratory irritation, nervous-system effects and skin defatting after repeated contact. Dizziness does not measure concentration and should not be accepted as normal work experience. Medical assessment needs information about every relevant mixture constituent and exposure condition, not only the substance recognised by its smell or most prominently named on the product label.
Measure the mixture appropriately
An occupational hygiene measurement should support interpretation of MEK and other solvents present. A general-reading instrument may respond to several substances without distinguishing them. Define whether the question concerns a shift or a short task, and record quantities, temperature, ventilation and opening time. Results from different reference periods should not be treated as equivalent exposure descriptions.
Compatibility and fire
MEK is highly flammable and can affect some plastics and elastomers. INRS records incompatibilities requiring review for the actual process. Do not combine product residues merely because both are labelled solvents. Containers, equipment and waste arrangements require technical selection, and interventions need procedures for the actual composition rather than an ambiguous abbreviated product name used in conversation.
Improve cleaning, not only gloves
An improvement may involve contained dispensing of the required quantity and reduced open surfaces. Verify preparation, application, waste removal and cleaning of the dispenser itself. Glove selection needs permeation information for the mixture and duration. A visually intact glove does not establish that solvent has not passed through it, so appearance alone cannot verify protective performance.
Record useful decisions
Retain identity, composition, measurement method and control reasoning. After a formulation change, review whether the assessment remains representative even if the trade name stays the same. Check current limits and conditions for the country of use. Absence of strong odour or complaints is not sufficient on its own to close an MEK exposure assessment or approve changed operations.
