Overview#
A material declaration is how one company tells the next one what's inside a part. It is structured so that compliance can be checked rather than guessed.
There are three depths, increasing in detail and effort. A supplier statement answers whether the part complies. A substance-list declaration reports how much of each listed substance is present. A full material declaration covers everything. Pick the shallowest one that answers the question.
Why it exists#
No factory sees its whole supply chain. To prove a product meets RoHS, REACH, POP and the rest, each tier has to pass composition data up to the next. Material declaration is that hand-off. Standardising it (for example with IEC 62474 or IPC-1752A) is what makes the data reusable instead of a thousand bespoke spreadsheets.
The three depths#
| Supplier statement | Substance-list MD | Full Material Declaration | |
|---|---|---|---|
| Answers | "Compliant with rule X?" | "How much of each listed substance?" | "What is everything made of?" |
| Effort | Low | Medium | High |
| Covers new rules? | Re-ask each time | If the substance is on the list | Re-check existing data |
| Know-how exposed | None | Listed substances only | Full recipe (can be partly anonymised) |
How much should you declare?#
The honest answer is the shallowest depth that satisfies the law and your customer. Deeper declarations cost more to produce and reveal more of your recipe, but they age better. A practical pattern is to let each tier declare the layer it actually knows: materials, then components, then assemblies, then the finished product.
A Full Material Declaration is the only depth that survives a future restriction without re-surveying suppliers, because the data is already there. Many teams treat it as the long-term goal even if they start shallower.
Mandatory vs. worth-watching#
Not every substance you'd report is banned. Declarations carry two kinds of flag.
A declarable substance tied to a live rule, such as a REACH SVHC or a RoHS substance. Reporting is required.
A worked example (illustrative)#
Take a generic panel connector: brass pins with a tin coating, in a glass-filled plastic housing. Here is the same part declared three ways.
- Supplier statement. "RoHS-compliant; lead in the brass is covered by an exemption." You learn nothing else.
- Substance-list MD. Lists the lead, plus any other listed substance present, with concentrations. You can check it against several rules.
- FMD. The brass alloy, the tin layer, the polymer, the glass fibre, the flame retardant, the pigment, every substance, every layer. You can answer any future question.
(Illustrative only, not real compliance data.)
Where the data formats fit#
IEC 62474 and IPC-1752A are the standard containers for all three depths. IPC-1754 extends them to whole articles. The reference list of what to declare comes from a substance list. Industry platforms such as BOMcheck collect these declarations from suppliers at scale, so the same data can be reused across many customers.
Which container you are asked for depends on who is asking.
| Format | Asked for by | Carries |
|---|---|---|
| IPC-1752A | Electronics | XML in classes A to D, from a compliance answer up to a full declaration |
| IMDS | Automotive | A Material Data Sheet per part in a shared database, reportable content from GADSL |
| CMRT and EMRT | Any chain touching conflict minerals | Smelters and country of origin for 3TG, extended to cobalt and mica |
| chemSHERPA | Japan | Two formats, AI for articles and CI for chemical products, on the IEC 62474 DSL |
CMRT and EMRT are maintained by the RMI, not by a standards body, and they answer a sourcing question rather than a composition one. They sit next to a material declaration rather than inside it.
Where declarations go wrong#
Most rejected declarations are not dishonest. They are filed against the wrong part, or they are true about a list that has since moved.
| What goes wrong | Why it breaks the declaration |
|---|---|
| Part numbers that do not match | The customer's number, your number and the supplier's number are three strings for one part. A declaration filed against the wrong one is worse than none |
| Percentages that do not close | A full material declaration is meant to account for 100 % of the part's mass. One that does not is not a full declaration, whatever it is labelled |
| Substances identified loosely | A trade name or an alloy grade where a CAS number was expected leaves the receiver guessing which substance was meant |
| Declarations that have aged | The Candidate List moved after the file was written, so the file is accurate about a list that no longer looks that way |
| Schema-valid but wrong | A file can pass the published schema and still contradict the bill of material behind it |
Schema validation and content validation are different checks. The first asks whether the file is shaped correctly, the second whether it says something true about the part. A tool that only does the first will pass a declaration that nobody can use.