One compound may have several values

A DNEL may relate to workers or the general population, inhalation or dermal contact, short- or long-term exposure, and local or systemic effects. These are different conditions. Before using a value, its meaning and units are checked. Comparing an air concentration with a dermal value without an appropriate exposure model is incorrect.

What distinguishes a DMEL?

A DMEL is used in risk-based approaches to effects without an established no-effect threshold, particularly certain carcinogens. Interpretation requires knowing the associated risk and derivation. The word minimal does not mean zero risk or itself guarantee protection for every exposed person.

Relationship to occupational limits

Occupational exposure limits and REACH-derived values have different contexts and procedures. A DNEL does not automatically displace a mandatory limit or allow a less demanding reference to be chosen for convenience. Assessment must identify applicable requirements and justify use of additional information where necessary.

Derivation quality and traceability

A value may originate from a registrant, and its basis and relevance must be reviewed. RIVM research on selected substances found important differences between derivations and highlighted the need for transparency; those findings should not be extrapolated to every DNEL. The practical lesson is to check the source, not accept or reject every value because of its label.

Incorrect comparison example

In a hypothetical example, a manager copies a short-term DNEL from a sheet and compares it with a full-shift average. Even if units match, the comparison concerns different periods. The technician identifies the relevant value, reviews the exposure scenario and retains both references if they serve different preventive questions.

Incorporating them into an assessment

Substance, population, route, duration, effect, units, date and source are recorded. Where the basis is missing or values conflict, supplier clarification is requested and reviewed with toxicological competence. A favourable result against one reference does not replace examination of other exposure routes, mixtures or measures required for the process.