GADSL, RoHS, and REACH

If you build, buy, or certify automotive parts, the Global Automotive Declarable Substance List (GADSL) is the foundation of chemical transparency across the supply chain. It tells you which substances must be declared (D) and which are prohibited (P) in vehicle components at the time of sale. GADSL is also the bridge to broader chemical regimes such as RoHS, REACH, ELV, and emerging reporting frameworks. This guide shows you—step by step—how to make GADSL work in real life: how to collect supplier data, how to use IMDS effectively, how to manage engineering changes, how to design safer parts, and how to use compliance as a competitive advantage.

Why GADSL Still Matters (Even If You Already “Do” RoHS and REACH)

Automotive supply chains aren’t just complex—they’re dynamic. Materials shift, suppliers change resins and coatings, engineering tweaks happen weekly, and customer-specific requirements pile up. GADSL is the shared language that lets OEMs and suppliers flag high-concern substances consistently. Even if you already comply with RoHS (Restrictions of Hazardous Substances in electrical/electronic equipment) and REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals in the EU), GADSL gives a targeted view of what must be declared or eliminated in automotive context. It’s the industry’s early-warning system to prevent last-minute redesigns, line stops, or blocked shipments.

In short:

GADSL = list of Declarable (D) and Prohibited (P) substances relevant to automotive parts at point of sale.

RoHS = limits certain heavy metals and flame retardants in EEE; crucial for automotive electronics.

REACH = manages SVHC notifications and restrictions; impacts automotive articles, materials, and supply-chain reporting.

ELV = automotive-focused substance restrictions and recycling requirements.

IMDS = the International Material Data System where you declare part-by-part composition; it operationalizes GADSL.

The Scope Rule That Trips People Up

GADSL applies to substances expected to remain in the final part at the time of vehicle sale. If a solvent evaporates during processing and doesn’t remain in the article, GADSL generally doesn’t require it to be declared. Conversely, residuals, impurities, coatings, platings, plasticizers, and flame retardants that remain in the component and exceed thresholds do matter. This nuance is why you must pay attention to homogeneous materials (just like RoHS) and to coatings/finishes that may carry restricted substances forward.

GADSL 101: Declarable vs. Prohibited, Thresholds, and Notes

Declarable (D): You must report the presence of the substance if it meets scope and exceeds the threshold. Declaration doesn’t necessarily mean you can’t use it—it means customers must know it’s there.

Prohibited (P): The substance must not be used in the specified application or material scope. Some prohibitions include exemptions or time-bound allowances; always read list notes carefully.

Thresholds: Measured typically at homogeneous material level (as you would for RoHS). Know the unit (ppm, mg/kg, weight %) and the scope notes (e.g., specific polymer types, vehicle sub-systems, or functional use).

Notes: Clarify time frames, use contexts, or exceptions. Notes are as important as the classification—don’t skip them.

How GADSL and IMDS Work Together

GADSL is the list; IMDS is the database. In IMDS, you submit material trees that break your part into materials and basic substances. IMDS checks your entry against rules—including GADSL flags. Customer-specific expectations (e.g., special lists, acceptance criteria) are layered on top.

Practical tips for IMDS:

Map your BOM to materials, not just part numbers. Each plastic, metal, adhesive, and coating should have a distinct entry.

Use correct basic substances (CAS or system entries) that reflect real composition. Avoid “dumping” everything under generic entries.

Align EBOM to MBOM: engineering and manufacturing BOMs should reconcile so declarations actually reflect the built configuration.

Version control your IMDS entries when ECNs/ECOs change a resin, pigment, plating, or adhesive.

Validate against GADSL flags before submission. Fix issues upstream instead of relying on customer rejections to catch problems.

GADSL vs. RoHS vs. REACH vs. ELV: Getting the Interplay Right

RoHS and GADSL: If you make automotive electronics, RoHS limits lead, mercury, cadmium, hexavalent chromium, and certain brominated flame retardants and phthalates in homogeneous materials. GADSL may also flag legacy leaded plating, BFRs in resins, or specific plasticizers in cables, gaskets, or housings.

REACH and GADSL: Under REACH, SVHCs above 0.1% w/w in articles may trigger communication and, in some cases, notification duties. GADSL highlights many of the same substances but in a way aligned with automotive reporting.

ELV and GADSL: The End-of-Life Vehicles directive focuses on recyclability and limits specific heavy metals and materials. GADSL helps operationalize those restrictions in part declarations.

Other frameworks: SCIP (Waste Framework Directive database), TSCA (US chemical management), and country-specific PFAS moves may intersect with your customers’ expectations. Even if not directly dictated by GADSL, your customer’s CSR, ESG, or brand policy can elevate voluntary restrictions.

Building a Lean—but Powerful—Controlled Substance Management System (CMS)

You don’t need a huge team; you need clarity and cadence.

Core components:

Policy & scope: Define which lists you follow (GADSL, RoHS, REACH, ELV, customer lists).

Roles & ownership: Name a single accountable owner, with engineering, purchasing, quality, EHS, and legal supporting.

Supplier onboarding: Bake compliance into RFQ, quality agreements, and PO terms—not as an afterthought.

Data model: One source of truth for part–material–substance mapping; include supplier evidence and revision history.

Change control: Tie compliance checks to ECN/ECO so formulation or supplier changes don’t slip through.

Risk rating: Score materials and suppliers (e.g., elastomers with phthalates, epoxies with halogens, plating with Cr(VI)).

Audit rhythm: Internal checks and supplier refresh cycles (e.g., annually).

Training: Short modules for engineers and buyers focusing on what they control.

Dashboards & KPIs: Track first-pass IMDS acceptance, supplier responsiveness, open corrective actions, RoHS/REACH incident rates.

Escalation & remediation: Clear path when a prohibited substance appears or a declarable crosses thresholds.

The 12-Step GADSL Compliance Workflow

Step 1: Inventory the universe

List your sellable parts and the materials within them: polymers, metals, coatings, adhesives, solders, cables, elastomers, batteries, labels, inks. Tie each to a supplier and spec.

Step 2: Tag the high-risk items

Elastomers with plasticizers, halogenated flame-retardant resins, pigmented plastics, platings/coatings with legacy heavy metals, soldered electronics—these deserve deeper scrutiny.

Step 3: Request data with specificity

Use supplier declarations aligned with GADSL and REACH SVHC logic. Ask for composition ranges, CAS identifiers, and intended use (e.g., pigment vs. additive). Include RoHS statements for electronic content.

Step 4: Validate evidence

Cross-check supplier declarations against material grades, TDS/SDS, and historical experience. For critical applications, request a Certificate of Analysis or third-party test report.

Step 5: Build accurate IMDS entries

Create the material tree with correct basic substances. Don’t approximate away the risk—if a brominated FR is used, list it. Let IMDS flag GADSL hits now, not after a customer reject.

Step 6: Run a GADSL/REACH/RoHS triage

For each flagged substance, verify scope (does it belong in the finished article?), threshold, and application notes. Separate Prohibited from Declarable items to drive decisions.

Step 7: Decide the path: permit, declare, or replace

If Prohibited in scope → redesign/substitute.

If Declarable → confirm above/below threshold; prepare disclosure.

If out of scope or under threshold → document rationale.

Step 8: Engineer the substitution (if needed)

Evaluate performance trade-offs: mechanical strength, dielectric properties, heat deflection, corrosion resistance, adhesion, UV stability. Avoid regrettable substitutions by checking all impacted requirements (safety, EMC, thermal).

Step 9: Pilot and validate

Run trials, dimension checks, reliability tests, and functional validation. Update prints, specs, control plans, and approved supplier lists.

Step 10: Lock in change control

Issue ECN/ECO, update IMDS, archive old versions, and communicate the cut-in point (serial number, date code, lot).

Step 11: Train the front line

Give engineers and buyers a one-page quick reference: what to avoid, what to declare, how to spot risk in datasheets.

Step 12: Monitor & improve

Schedule list updates, supplier refreshes, and internal audits. Track KPIs and drive corrective actions.

The Electronics Deep Dive: Where RoHS, REACH, and GADSL Collide

Electronics in vehicles bring the toughest overlaps:

Solders & platings: Watch for lead in old specs, and hexavalent chromium in passivation.

Brominated FRs in PCBs: Certain brominated flame retardants are common in laminates; confirm actual FR system and whether it triggers GADSL declaration or RoHS issues.

Phthalates in cables: Some phthalates are banned by RoHS and can also be flagged by GADSL or REACH.

Adhesives & potting compounds: Epoxies, silicones, and polyurethanes can carry restricted catalysts or plasticizers.

Platings on fasteners and connectors: Cr(VI) concerns persist in legacy drawings; verify actual process (Cr(III) vs Cr(VI)).

Marking inks & labels: Pigments may contain metals or other listed substances—small mass, but at homogeneous level they can matter.

Checklist for electronics:

Confirm laminate (FR system), solder alloy, conformal coating, connector plating, cable jacket, adhesive.

Validate RoHS compliance at homogeneous level.

Run IMDS with realistic basic substances.

Ensure REACH SVHC assessment for housings, gaskets, adhesives, and cable assemblies.

Keep a substitution playbook for FRs and plasticizers.

Polymers, Elastomers, and Coatings: The Usual Suspects

Plasticizers (phthalates and non-phthalates): Seen in PVC cables, flexible elastomers, and soft overmolds.

Flame retardants: Brominated or phosphorus-based systems—know which you use.

Pigments: Some inorganic pigments contain metals subject to declaration.

Coatings: Anti-corrosion systems and primers can be hotspots if specs are outdated.

Practical move: Create a material whitelist for common families (PC/ABS, PA66, PBT, TPU, EPDM, NBR) with pre-vetted grades that meet GADSL/RoHS/REACH expectations.

Metals and Surface Treatment: Hidden Risk in the Finish

Chromate conversion coatings: Verify whether they are trivalent or hexavalent.

Alloying elements: Residuals can matter if they migrate into a coating or are present in a homogeneous layer.

Plating baths: Only in-scope if residuals remain on the finished article; still, they’re a strong indicator to ask more questions.

Frequently Asked Questions (Short Answers You Can Paste)

Q: If a declarable substance is present below threshold, do I still declare it?

A: No—but keep records that show how you determined it’s below threshold.

Q: Our supplier claims the additive is proprietary; what now?

A: Request a confidential declaration or third-party verification. Many suppliers can reveal CAS-level data under NDA or via a third party while protecting IP.

Q: How often should we refresh declarations?

A: At least annually for high-risk materials and whenever an ECN/ECO or supplier change occurs.

Q: Does RoHS apply to non-electronic parts?

A: RoHS specifically targets electrical and electronic equipment; however, mixed assemblies often blend electronic and non-electronic items. If your part is part of an electrical/electronic assembly, assume RoHS may apply to its homogeneous materials.

Q: How do REACH SVHCs interact with GADSL?

A: Many SVHCs appear in GADSL because customers need visibility. If an SVHC is present above 0.1% w/w in an article, communication obligations may apply, independent of GADSL.

Bottom Line

GADSL is not bureaucracy—it’s your operational shield. When you pair it with RoHS and REACH know-how, you prevent late surprises, accelerate customer approvals, and design parts that stay compliant as rules evolve. Build a lightweight CMS, keep your IMDS honest, and make change control the heartbeat of your program. The result is more than compliance: it’s resilient engineering, smarter sourcing, and a reputation your customers trust.