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One free scan finds every outdated or missing driver and matches the right update for your exact hardware.Free scan · exact hardware matchA 2021 study found that 99.4% of 492 assessed chemical products exceeded at least one planetary boundary under the authors’ absolute environmental sustainability assessment. That result does not mean nearly all chemicals are toxic or harmful in every use. It means their assessed environmental impacts exceeded ecological budgets allocated to them under a particular method.
What the 99.4% result means
Victor Tulus, Javier Pérez-Ramírez and Gonzalo Guillén-Gosálbez evaluated 492 chemical products using planetary-boundary-based absolute environmental sustainability assessment (AESA). A chemical was counted as transgressing a boundary when its estimated impact exceeded the share of ecological capacity assigned to it. In this framework, a transgression level greater than 1 means the allocated budget is exceeded.
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The authors reported that 99.4% of the assessed chemicals transgressed at least one of the boundaries they measured. The result is a thresholded assessment, not a finding that all those chemicals are equally damaging, unsafe for people, or unsustainable under every possible production route. Some calculated transgression levels were more than 200 times the allocated budget, while others were much lower. The paper, published in Green Chemistry on 27 October 2021, describes the method and its results.
How the study assessed the chemicals
The authors linked life-cycle inventory flows—such as emissions and resource use—to planetary-boundary control variables using characterization factors. They then compared the impact associated with each chemical to an allocated share of ecological capacity. The allocation matters: how the global safe operating space is divided among products can affect whether an assessment crosses the threshold.
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The study assessed seven of the nine planetary-boundary processes:
- Climate change
- Stratospheric ozone depletion
- Ocean acidification
- Biogeochemical flows
- Land-system change
- Freshwater use
- Change in biosphere integrity
It did not assess atmospheric aerosol loading because the study lacked a defined global boundary for it. It also excluded novel entities because a suitable control variable was not yet available. So the 99.4% figure does not represent a measurement across all nine boundaries.
Why this is different from a standard life-cycle comparison
Conventional life-cycle assessment (LCA) indicators can compare the environmental impacts of products or processes. AESA asks a different question: do those impacts fit within a defined share of Earth’s ecological capacity? In a relative comparison, one product may perform better than another even if both exceed a planetary budget. An absolute assessment adds that budget threshold.
| Assessment lens | What it tells you | What it does not establish by itself |
|---|---|---|
| Relative life-cycle indicators | How impacts compare between products or production routes, using indicators such as carbon footprint. | Whether the impact fits within an allocated share of ecological capacity. |
| Absolute sustainability assessment | Whether an impact exceeds an allocated planetary-boundary budget; in this study, a transgression level above 1 marks an exceedance. | A universally agreed regulatory classification or a judgment that a chemical is unsafe in every context. |
AESA can complement standard LCA, but it is not an agreed replacement. The authors note that allocating ecological capacity requires agreement; a pass-or-exceed result depends in part on how that capacity is downscaled and assigned.
Why a lower carbon footprint does not prove sustainability
The study found especially high transgression in carbon-related boundaries, including climate change, ocean acidification and change in biosphere integrity. However, the authors found no correlation between a chemical’s carbon footprint and its overall absolute sustainability transgression levels. A lower carbon footprint therefore does not show that a chemical stays within every assessed planetary budget: other environmental pressures can still exceed their allocated limits.
What to make of the named exceptions
Chemistry World reported that hexamethyldisilazane, selenium and trimesoyl chloride were the only three chemicals in the study’s set that met the absolute criterion. That list is attributed to the publication’s account; it should not be read as a general certification of those substances, or as a result established for every production route or use. Chemistry World also quoted ETH Zürich professor Javier Pérez-Ramírez describing the assessment as covering “pretty much the main chemicals that you can find in the market.”
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How current is the finding?
This is a result from a paper first published in 2021, not a new survey of chemicals currently on sale. The sources reporting the study do not establish that the same 492 products have since been reassessed. The finding is best understood as an application of an absolute-sustainability method to that study’s chemical set, with its seven-boundary coverage and allocation assumptions.
The authors presented AESA as a way to extend life-cycle assessment with planetary limits. Their result highlights why product comparisons and absolute ecological budgets answer different questions; it does not, on its own, settle how a chemical should be regulated or which production changes would bring a given product within a budget.
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