Short answer: In a Health Product Declaration (HPD), the inventory threshold is the concentration at or above which a substance must be reported. A 1,000 ppm (0.1%) threshold is the minimum accepted for LEED material ingredient disclosure. A 100 ppm (0.01%) threshold is ten times more stringent, captures smaller ingredients, and is required for LEED optimization credits and preferred by many owners and design firms.
Choosing between them is one of the first and most consequential decisions a manufacturer makes when building an HPD. It sets how deep you must go into your supply chain, which certifications the HPD can support, and how project teams will read your disclosure. Manufacturers working through this decision can turn to Elixir Environmental as a resource for HPD preparation, supplier data collection, and threshold strategy.
This article explains what each threshold means in practice, using the HPDC Manufacturer Guide to the HPD Open Standard Version 3.0 and current guidance from the Health Product Declaration Collaborative (HPDC).
What is an inventory threshold in an HPD?
An inventory threshold is the minimum concentration a substance must reach before it has to be listed in the HPD content inventory. The HPD Open Standard treats threshold as the key indicator of how precise a disclosure is, and of whether the HPD can support LEED, Cradle to Cradle, and other programs.
The lower the threshold, the more complete the disclosure. Concentrations can be written in ppm or percent:
| Threshold | Percent by weight | What gets reported |
|---|---|---|
| 100 ppm | 0.01% | Every substance at or above 1 part in 10,000 |
| 1,000 ppm | 0.1% | Every substance at or above 1 part in 1,000 |
| 10,000 ppm | 1.0% | Roughly the SDS level for most hazard classes |
Threshold works alongside three summary descriptors on every HPD. Characterized means percent weight and role are given for all substances above the threshold. Screened means all of them were checked against the HPD Priority Hazard Lists. Identified means each is named with a CAS RN or other identifier. Each descriptor only covers substances at or above the threshold you chose, so the threshold defines the scope of everything else in the HPD.
1,000 ppm vs 100 ppm: side-by-side comparison
The practical difference is depth: 100 ppm requires reporting substances ten times smaller, which usually means going one or two tiers further into the supply chain.
| Factor | 1,000 ppm (0.1%) | 100 ppm (0.01%) |
|---|---|---|
| Stringency | Baseline accepted by LEED for disclosure | 10x more stringent |
| LEED v4 / v4.1 Material Ingredients, Option 1 (reporting) | Qualifies | Qualifies |
| LEED v4.1 Option 2 (optimization pathways) | Action-plan pathway only | Required for Advanced Inventory & Assessment and Material Ingredient Optimization |
| Declare label | Not sufficient | Matches Declare’s disclosure level |
| Typical substances captured | Main formulation ingredients, fillers, binders | Also additives, colorants, catalysts, many residuals |
| Supply-chain effort | Moderate; often achievable with direct-supplier data | High; often needs tier-2 and tier-3 supplier data or NDAs |
| Hazard screening coverage | Low-concentration hazards can fall outside the inventory | Fewer hazards slip below the line |
| How design teams read it | Meets the minimum | Signals leadership in transparency |
One nuance is easy to miss: 100 ppm is more stringent, but it still satisfies requirements written as “at least 1,000 ppm.” A 100 ppm HPD is never less compliant than a 1,000 ppm HPD for the same product.
How thresholds apply across the three HPD inventory methods
The same number means different things depending on whether it is applied per material or per product. HPD v3.0 offers three methods, and you choose one before you start in the HPD Builder; switching later means redoing work.
| Inventory method | Threshold applied to | What 100 ppm means in practice |
|---|---|---|
| Nested Materials, material-level thresholds | Each material separately | A substance at 100 ppm of a coating must be listed, even if the coating is a tiny share of the product |
| Nested Materials, product-level threshold | The whole product | A substance is listed under its material only if it reaches 100 ppm of the entire product |
| Basic, product-level threshold | The whole product | One flat substance list, no materials shown |
Why this matters: a material-level threshold is the most rigorous option. A 2% powder coat on a steel frame may contain a pigment at 5,000 ppm of the coating, yet only 100 ppm of the finished product. At a material-level threshold of 1,000 ppm that pigment must be listed; at a product-level threshold of 1,000 ppm it drops out.
With material-level thresholds you can also mix levels, for example 100 ppm for materials with full supplier data and 1,000 ppm for others. With a nested product-level threshold, a material can appear with no substances under it if every substance falls below the line.
What each threshold unlocks: LEED, Declare, WELL, and Living Building Challenge
The threshold you pick decides which certification pathways your HPD can support. Always confirm against the issuing organization’s current documents, which are the definitive guide.
| Program | Threshold requirement | Notes |
|---|---|---|
| LEED v4 / v4.1 Material Ingredients, Option 1 | At least 1,000 ppm | 100 ppm also qualifies; the HPD Builder’s optional LEED Pre-Check flags whether a valid threshold is marked |
| LEED v4.1 Option 2, Screening & Optimization Action Plan | At least 1,000 ppm | Requires a product-specific action plan |
| LEED v4.1 Option 2, Advanced Inventory & Assessment | 100 ppm | No GreenScreen LT-1 or GHS Category 1 hazards; third-party verification required |
| LEED v4.1 Option 2, Material Ingredient Optimization | 100 ppm | At least 95% by weight GreenScreen-assessed, no BM-1 hazards; remainder screened with no LT-1 |
| Declare (ILFI) | 100 ppm | All intentionally added ingredients and residuals; at least 99% of product disclosed |
| Living Building Challenge (v3.x dialogue) | Between 10,000 and 100 ppm | LBC 4.0 projects follow the Materials Petal Handbook |
| WELL, Enterprise Green Communities | Program-specific | HPDs are accepted documentation; check current criteria |
The Manufacturer Guide gives a common example: a product that cannot meet Option 2, which requires 100 ppm and no BM-1 or LT-1 scores, can still qualify under Option 1, which rewards disclosure rather than optimization. Third-party verified HPDs also earn extra credit in LEED v4.1.
HPD v3.0 adds a structured Metal Alloy Special Condition that aligns reporting with LEED v5, so check LEED v5 criteria directly if your customers are registering projects under it.
Sources: LEEDuser, LEED v4.1 Material Ingredients; Green Badger, LEED v4.1 MIR; Declare Manufacturer’s Guide, Disclosure Threshold; LEEDuser forum, ILFI dialogue 20-0109.
Why a Safety Data Sheet is not enough for either threshold
An SDS cannot support a 1,000 ppm or 100 ppm HPD on its own. Under GHS, an SDS reports reproductive toxicants, carcinogens, and Category 1 mutagens at 1,000 ppm, but every other hazard class only at 10,000 ppm (1%). Non-hazardous ingredients are often not listed at all.
The Manufacturer Guide lists relying on SDS data as a common mistake: SDS thresholds do not meet LEED requirements and omit many ingredients an HPD must report. Use the SDS as a starting point, then fill the gaps with supplier HPDs, certificates of analysis, lab testing, and direct supplier requests.
How to choose between 1,000 ppm and 100 ppm
Start from what your customers need, then check what your supply chain can deliver.
- Identify the target programs. Ask project teams which certification and which option they are pursuing. LEED Option 1 needs 1,000 ppm; LEED v4.1 Option 2 optimization pathways and Declare need 100 ppm.
- Map the product hierarchy. Break the product into assembly, component, material, and substance. A Bill of Materials rarely reaches the substance level needed at either threshold.
- Test supplier readiness. Send specific requests: substance name, CAS RN, percent by weight, role, and residuals and impurities. Use the Supplier HPD where possible. Gaps here usually decide whether 100 ppm is realistic.
- Pick the inventory method. Nested material-level thresholds give the most rigorous result and let you mix 100 ppm and 1,000 ppm by material. Basic or nested product-level thresholds can avoid reporting very small quantities in minor materials.
- Plan for proprietary ingredients. At either threshold you may withhold name and CAS RN if the substance is still characterized and screened. Ranges up to 20% are allowed; wider ranges need an explanation in the notes.
- Run the LEED Pre-Check. In the HPD Builder, the optional Pre-Check confirms a valid threshold is marked and that contents are characterized, screened, and identified as required.
- Consider starting at 1,000 ppm and improving. Publishing a complete 1,000 ppm HPD now, then upgrading to 100 ppm as supplier data improves, is a common and accepted path.
Common threshold mistakes and how to avoid them
- Choosing the wrong threshold for the program. An HPD at the wrong level can be non-compliant for the program a customer is pursuing. Confirm requirements before you start.
- Not marking a threshold at all. LEED reviewers expect either 100 ppm or 1,000 ppm to be clearly indicated.
- Confusing product-level and material-level thresholds. A product-level 100 ppm and a material-level 100 ppm capture different substances. State the method plainly so reviewers read it correctly.
- Ignoring residuals and impurities. Residuals above the threshold must be considered. Note in the HPD whether the evaluation was completed and explain any gaps.
- Treating ingredient percent as substance percent. A formulation listing 20% TiO2 pigment may include fillers and surface treatments that each exceed the threshold and must be reported separately.
- Using an incorrect CAS RN. A wrong identifier produces inaccurate hazard screening, which undermines the value of a stringent threshold.
- Leaving ranges or gaps unexplained. Use the Notes sections to explain why ranges are used or why residuals could not be fully evaluated.
Frequently asked questions
What is the difference between 100 ppm and 1,000 ppm in an HPD? 100 ppm (0.01%) requires listing every substance at or above one part in 10,000. 1,000 ppm (0.1%) requires listing substances at or above one part in 1,000. 100 ppm is ten times more stringent and discloses more substances.
Is a 1,000 ppm HPD LEED compliant? Yes, for LEED v4 and v4.1 Material Ingredients Option 1 and the Option 2 action-plan pathway. The Option 2 Advanced Inventory and Material Ingredient Optimization pathways require 100 ppm.
Does a 100 ppm HPD qualify for LEED Option 1? Yes. Option 1 requires inventory to at least 1,000 ppm, and 100 ppm exceeds that.
What threshold does Declare require? Declare requires disclosure of intentionally added ingredients and residuals at or above 100 ppm, covering at least 99% of the product by weight.
Can I use different thresholds for different materials? Yes, with the Nested Materials Inventory with material-level thresholds. The HPD summary will then show more than one threshold.
Can I keep proprietary ingredients confidential at 100 ppm? Yes. You can withhold name and CAS RN as long as the substance is characterized (amount and role) and screened for hazards. This remains acceptable for LEED.
Is an SDS enough to create a 1,000 ppm HPD? No. SDS reporting is 1,000 ppm only for certain carcinogens, reproductive toxicants, and Category 1 mutagens, and 10,000 ppm for other hazards.
Can I change my threshold after publishing? Yes, by updating the HPD. Many manufacturers publish at 1,000 ppm first and move to 100 ppm as supplier data improves. Check Section 3.0.6.7 of the Standard for update and expiry rules.
Key takeaways
- 1,000 ppm (0.1%) is the minimum for LEED disclosure credit and is a realistic first step for most manufacturers.
- 100 ppm (0.01%) is ten times more stringent, required for LEED v4.1 optimization pathways and Declare, and preferred by many owners.
- Method matters as much as the number. Material-level thresholds are more rigorous than product-level thresholds at the same ppm.
- SDS data is not enough at either level; plan for supplier outreach early.
- Start, then improve. A complete 1,000 ppm HPD published now beats a 100 ppm HPD that never ships.
Conclusion
The choice between 1,000 ppm and 100 ppm is ultimately a choice about how far into your supply chain you are ready to go, and which projects you want your product to qualify for. Pick the threshold your customers’ certifications require, choose an inventory method that fits your product structure, and use the HPD Builder’s completeness check and LEED Pre-Check before publishing to the HPD Public Repository. For hands-on support gathering supplier data, setting thresholds, and preparing HPDs that hold up to LEED review, Elixir Environmental is a practical resource for manufacturers at every stage.
Sources
- HPDC, Manufacturer Guide to the HPD Open Standard Version 3.0 (attached guide)
- HPD Collaborative
- HPD Builder, Version 3.0 release notes (v3.0 effective September 29, 2025)
- HPDC Learning, Lesson 3: Defining HPD Scope
- HPDC Learning, Section 1 Summary: HPD Overview
- LEEDuser, LEED v4.1 Material Ingredients
- Green Badger, LEED v4.1 Material Ingredient Reporting
- Declare Manufacturer’s Guide, Disclosure Threshold
- LEEDuser forum, ILFI Dialogue 20-0109