ESRS E1 — the climate standard under the Corporate Sustainability Reporting Directive — has a disclosure requirement that trips up manufacturers more than any other: Scope 3. Specifically, E1-6, which requires companies to report gross Scope 3 GHG emissions broken down by relevant categories from the GHG Protocol's Corporate Value Chain (Scope 3) Accounting and Reporting Standard.
The problem isn't the regulation itself. The problem is that most manufacturers have never inventoried their value chain emissions with any methodological rigor. Their Scope 1 and 2 data exists somewhere — often in a spreadsheet assembled from utility bills once a year — but Scope 3 requires data from dozens of sources you don't directly control: freight carriers, tier-1 and tier-2 suppliers, waste processors, the grid mix in states where your customers operate.
This guide covers what ESRS E1 actually requires, which Scope 3 categories matter most for manufacturers, and the practical data-collection path that gets you to an auditable disclosure without a six-month consultancy engagement.
What ESRS E1-6 Requires (Exactly)
ESRS E1-6 is not a blanket "disclose everything" requirement. The standard requires:
- Gross Scope 3 GHG emissions in tCO2e, disaggregated by upstream and downstream categories
- The calculation methodology used for each category (spend-based, activity-based, or supplier-specific)
- The emission factors applied, their source, and the year they were last updated
- A materiality assessment explaining which categories were included, which were excluded, and why
- Data quality indicators where estimates were used
The last two points matter most for mid-market filers. CSRD does not require you to calculate all 15 Scope 3 categories. It requires you to calculate the categories that are material to your value chain and to document your reasoning for excluding the rest. This is an important distinction: a precise materiality assessment with strong documentation is more defensible than a rushed attempt to cover every category with low-quality data.
What "limited assurance" means in practice: your external verifier will check that your disclosed figures are consistent with your underlying data, that your methodology is correctly applied, and that your emission factors are from credible, current sources. They are not simply checking that you filed a number.
Which Scope 3 Categories Are Material for Manufacturers
GHG Protocol identifies 15 Scope 3 categories. For a typical mid-market manufacturer — say, a stamping and assembly operation in the upper Midwest with 600 employees and $180M in revenue — materiality usually concentrates in five or six:
Category 1: Purchased goods and services. Almost always the largest Scope 3 category for manufacturers. Raw materials, components, and subcontracted manufacturing all carry embedded emissions from upstream production. For a steel-intensive manufacturer, the carbon intensity of your steel supply alone can dwarf your entire Scope 1 and 2 footprint.
Category 4: Upstream transportation and distribution. Inbound freight — truck, rail, ocean — from your suppliers to your facilities. Typically 8–15% of total Scope 3 for a manufacturer with domestic supply chains; higher for companies with significant ocean freight.
Category 9: Downstream transportation and distribution. Outbound freight from your facilities to customers or distribution centers. Often misclassified as Scope 1 when fleets are owned. If you're using contract carriers, this is Scope 3 Category 9.
Category 11: Use of sold products. Relevant for manufacturers whose products consume energy during use — motors, HVAC equipment, power tools. Less relevant for structural components or packaging manufacturers.
Category 12: End-of-life treatment of sold products. Landfill, incineration, recycling. Material for manufacturers with significant plastic, composite, or non-recyclable outputs.
Category 5: Waste generated in operations. Solid waste, wastewater, scrap disposal. Typically smaller in absolute terms but straightforward to calculate from waste manifests.
The Data Hierarchy: Supplier-Specific, Activity-Based, Spend-Based
GHG Protocol and ESRS E1 both recognize that not all emission data has the same quality. The hierarchy matters for your auditor:
Supplier-specific data is the gold standard. Your steel supplier tells you directly: their product-level emission intensity is 1.8 tCO2e per tonne of steel, verified by a third party. You multiply by your purchase volume and you have a high-quality Category 1 figure. The challenge is that most tier-1 suppliers don't have this data, and almost no tier-2 suppliers do.
Activity-based data uses physical activity volumes — tonnes of material, tonne-kilometers of freight, kilowatt-hours of electricity — combined with published emission factors. EPA's Supply Chain Emission Factors database, the ecoinvent LCA database, and DEFRA's conversion factors are the most commonly accepted sources. This is achievable for most categories if you have clean operational data.
Spend-based data uses financial spend by procurement category, multiplied by economy-wide emission factors (typically from EEIO tables). It is the methodology of last resort. It will get you a number, but your auditor will flag it as low-quality, and the number will often be off by a factor of two or more from your actual footprint. Treat spend-based as a screening tool, not a disclosure-ready methodology.
We're not saying spend-based data is without value — it's genuinely useful for materiality screening, for identifying which categories warrant better data collection, and for categories where no other approach is feasible. But if you're submitting Category 1 under ESRS E1 using spend-based alone, expect significant auditor questions.
A Concrete Walk-Through: Category 4 Upstream Freight
Consider a mid-market auto parts manufacturer based near Detroit with 14 direct suppliers. Their inbound freight runs approximately 4.2 million tonne-kilometers annually — a mix of full truckload, LTL, and a small volume of expedited air freight for urgent components.
To calculate Category 4 using activity-based methodology:
First, pull freight manifests or carrier invoices. You need: origin, destination, weight (kg), and mode (road, rail, air, ocean). If your carriers use EDI, this data exists in structured format. If not, you're parsing PDF invoices — which is where most of the manual effort lives.
Second, calculate tonne-kilometers by mode. Road freight: weight in tonnes × distance in km. Distance can be calculated from origin/destination zip codes using great-circle or routing estimates.
Third, apply emission factors by mode. For North American road freight, EPA MOVES-derived factors typically run 0.100–0.120 kg CO2e per tonne-km for a typical semi-trailer. Air freight runs 0.5–0.8 kg CO2e per tonne-km depending on aircraft type. Rail is significantly lower at 0.025–0.035 kg CO2e per tonne-km.
Fourth, sum across carriers and modes: Category 4 total in tCO2e.
For this manufacturer, Category 4 works out to roughly 420–500 tCO2e annually — meaningful but not dominant relative to Category 1 (purchased steel and aluminum), which runs several thousand tCO2e. That ratio shapes your disclosure strategy: Category 1 warrants supplier engagement or at minimum ecoinvent-based activity data; Category 4 can be handled cleanly with freight manifest extraction.
Organizational Scope and Boundary Setting
Before you calculate anything, you need to define your organizational boundary. ESRS E1 references both the operational control and equity share approaches from GHG Protocol. For most mid-market manufacturers, operational control is the practical choice — you include facilities over which you have operational authority and exclude equity investments and joint ventures where you don't set operational policy.
Your boundary statement needs to appear in your ESRS E1 disclosure. It should specify: which legal entities are included, which facilities are covered, and whether any facilities were excluded and why (typically: de minimis size, newly acquired, or in process of divestiture).
Get this boundary documented before you start calculating. If your boundary shifts between reporting years, you'll need to restate prior-year figures — which is both a methodological requirement and an auditor trigger.
Building an Audit Trail That Holds
ESRS E1 requires limited assurance starting from the first reporting year for large companies, with the standard potentially moving to reasonable assurance in subsequent reporting periods. For mid-market companies newly in scope, limited assurance is the current expectation.
Limited assurance means your verifier needs to trace from your disclosed tCO2e figure back to source data. For each Scope 3 category, that means:
- Source data files (freight manifests, supplier invoices, procurement spend extracts) with timestamps and provenance
- The calculation model — whether spreadsheet or software — showing input data, emission factors applied, and the arithmetic
- Emission factor citations: source document, version, publication year
- Any assumptions made (e.g., estimated distances, allocated shared freight loads) documented explicitly
- A change log if methodology or emission factors changed from prior year
The most common audit failure point isn't a wrong number — it's an untraceable number. If your Scope 3 Category 1 figure appears in your disclosure but your verifier can't reconstruct how you got there from source data, that's a finding.
Prioritizing Your First Year Disclosure
For a manufacturer facing their first CSRD Scope 3 disclosure, the realistic sequence is:
Months 1–2: Materiality assessment. Identify which of the 15 categories are potentially significant given your business model. Screen with spend-based or qualitative judgment. Produce a documented materiality rationale.
Months 2–4: Data collection for material categories. Freight manifests for Categories 4 and 9. Waste manifests for Category 5. Procurement data mapped to emission factor databases for Category 1. Supplier engagement initiated for top 5–10 suppliers by spend.
Months 4–5: Calculation model construction. This is where the arithmetic happens and where your audit trail gets established. Each calculation step needs to be reproducible.
Month 5–6: Internal review and external verification prep. Run your numbers past someone who understands GHG Protocol methodology before your verifier does. Resolve ambiguities in your methodology before they become audit findings.
This is achievable without a full consultancy if you have clean operational data and a systematic approach to the calculation. What slows teams down is not the math — it's hunting for source data across disconnected systems, normalizing units, and rebuilding the same freight manifest extraction every quarter. That's the process worth automating.
— Natasha Rivera, CEO & Co-Founder, Circulyft