How to declare a substance that belongs to two different substance groups in IEC 62474

A material declaration that conforms to IEC 62474 requires that a declared substance must be assigned to it’s respective substance group (if the substance group is declared in the material declaration). In most material declarations this is straightforward. However, there is a corner case emerging when a substance has two or more possible declarable substance groups that are reportable. For example, the REACH SVHC substance “Lead sulfochromate yellow” creates such a situation. The declarable substance groups “Lead/Lead Compounds” and “Chromium (VI) Compounds” are both relevant. Howevever, it’s not possible to have “Lead sulfochromate yellow” declaration assigned to both substance groups simultaneously in the XML file. This situation potentially creates a small amount of double reporting for users that roll-up the total content of specific substances/elements. The IEC 62474 standard is vague on how to deal with this.

Let’s look at this situation in more detail….

Subclause 4.2.3(a) states “… Such substances shall be assigned to the substance group (if the substance group has a mandatory reporting requirement) or otherwise to the product part (if 4.2.2 applies) or otherwise to the product.”. Subclause 4.3.4(a) is similar. The key phrase is “assigned to the substance group”; however, there is no information or guidance in the IEC 62474 standard as to what is “ the substance group” for Lead sulfochromate yellow. You can’t necessarily jump to the conclusion that it is all declarable substance groups that have Lead sulfochromate yellow as a member.

Several possibilities for assigning the substance group arise; for example, the cation substance group could always be used (if applicable) or the anion substance group could be used. The substance group field in the declarable substance entry in the database could also be used to specify the substance group that should be used for the declarable substance; however, the substance group isn’t specified for most declarable substances in the DSL. Given that this situation was hypothetical at the time of writing the standard, there was reluctance to explicitly address this in the standard. The general intention, if this situation were to ever arise (which it has) was to let the responder (supplier filling out the material declaration) use their discretion to select the assignment of a declarable substance to a substance group.

So where’s the double reporting… the double reporting comes in because both declarable substance groups “lead/lead compounds” and “chromium (VI) compounds” must be declared. The Lead sulfochromate yellow substance declaration can only be assigned to one of these. If it’s assigned to lead/lead compounds, there is duplication in chromate mass because the current xml schema has no way to link the Lead sulfochromate yellow with the chromate substance group entry.