Hazardous substances in the anthropogenic stock
Why We Need to Rethink How We Deal with Contaminated Materials
Hazardous substances are one of the major, unpopular topics in the construction and environmental debate. They are complex, emotionally charged, and politically sensitive. They reliably return to the agenda whenever circular economy, resource protection, and sustainable construction are discussed.
This is no longer about isolated cases or historical contaminated sites. It is about a fundamental question:
How do we, as a society, deal with the substances that we ourselves have put into circulation and that are now part of our built environment?
The answer will determine whether the circular economy becomes a viable model for the future – or fails due to its own contradictions.
The Earth Is a Closed System
A central starting point is as simple as it is uncomfortable: we live in a closed system. There is no “outside” to which we can permanently dispose of substances. Whatever has been produced, installed, or distributed remains part of this system – visible or invisible, used or stored.
Over decades, the construction sector in particular has moved enormous quantities of material. Buildings, roads, bridges, and technical structures are not only infrastructure—they are also repositories: repositories for raw materials, for energy, and indeed for hazardous substances.
This anthropogenic – i.e., man-made – stock is a reality. It is neither good nor bad; it is the result of our economic and technological progress.
Anyone talking about the circular economy today must accept this stock as the starting point—anything else is theory. Hazardous substances are part of history and therefore part of responsibility.
Many substances we view critically today were considered technically sensible or even progressive at the time they were used. Asbestos was a high-performance material; certain additives improved the properties of building materials; industrial by-products were used to conserve resources.
With today’s knowledge, we assess these decisions differently – and rightly so. But that does not change the fact that these substances exist. They do not disappear simply because we now consider them problematic.
The key question, therefore, is not whether we like or dislike hazardous substances. It is whether we are willing to take responsibility for how we handle them—rather than pushing them out of sight.
From Linear Disposal to a Systemic Approach
For a long time, the handling of hazardous substances followed a linear logic: identify, remove, landfill. In the short term, this suggested safety; in the long term, it primarily caused one thing: a displacement of problems – spatially, temporally, and often politically.
In a circular economy, this way of thinking reaches its limits. If materials are to remain in the system for as long as possible, the question inevitably arises: how do we deal with contaminated components? A simple “get rid of it” no longer works without creating new conflicts of objectives.
Substance Content Is Not the Same as Risk
A key point that is often overlooked in public debate is the distinction between substance content and hazard.
A material can contain hazardous substances without automatically being dangerous. What matters is not merely that a substance is present, but:
- in what form,
- how firmly it is bound, and
- whether—and during which activities—it can actually be released.
Mineral building materials, in particular, often contain hazardous substances such as heavy metals (lead, chromium, nickel, zinc, etc.) that are chemically or physically bound. They are part of stable structures, embedded in crystal lattices or solid matrices. In this form, they are generally not mobile and not bioavailable in the installed state—meaning they cannot be taken up by living organisms.
A building, a road, or a technical structure does not automatically become a source of danger to users or the environment as a result. Risk arises only when substances are released through processing—for example through improper dismantling, dust-intensive methods, or chemical mobilization.
In other words:
The risk lies in how materials are handled – not in their mere presence.
Dismantling as a Key Point of Responsibility
This is exactly where the demolition industry comes in. Dismantling is not simple tearing down—it is a highly specialized process. It determines whether materials are handled in a controlled, safe, and differentiated manner, or whether unnecessary risks arise. The dismantling contractor is the heart surgeon of the urban mine.
Low-dust methods, protective measures, targeted separation, testing, and documentation are now state of the art. They make it possible to deal responsibly with contaminated materials without imposing blanket exclusions.
Undifferentiated regulation at the material level would undermine this practice. It would not lead to greater safety, but to a loss of control options. Materials would be excluded from the cycle across the board—regardless of whether they actually pose a hazard.
The Side Effects of Blanket Bans
Such an approach would have far-reaching consequences:
- valuable raw materials would be lost,
- landfill capacities would be additionally burdened,
- demand for primary raw materials would rise,
- emissions from new production and transport would increase, and
- dismantling, remediation, conversion, and new construction (and refurbishment) would become more expensive.
All of this without achieving a proportional gain in safety. Because what is landfilled is not automatically “safe”—it is merely removed from the visible cycle. Responsibility is shifted, often to future generations.
The Circular Economy Requires Differentiation
A functioning circular economy can only succeed if it differentiates. It must distinguish:
- between bound and mobilizable substances,
- between use and processing, and
- between theoretical hazard potential and real exposure.
This does not mean downplaying risks. On the contrary: it means taking them seriously where they actually arise—and regulating them where they can be controlled.
Regulation should therefore think more in terms of processes rather than assessing materials in a blanket manner. It should understand dismantling as the decisive lever and intervene where expertise, technology, and control take effect.
Thinking Responsibility Further – Also for the Future
A frequently overlooked aspect is the long-term view. Materials that are considered problematic today will be reassessed in the future as well. Analytical methods continue to evolve, and new technologies emerge.
The question is whether we will still be able to investigate and treat these materials in a targeted way then—or whether they will already have been permanently sealed off or mixed too heavily with other “waste,” with no access and no opportunity to learn.
The circular economy also means keeping options open—for better solutions, new methods, and future knowledge.
Shaping the Debate Proactively
The political relevance of hazardous substances will continue to grow. If the industry does not explain, categorize, and propose solutions early on, there is a risk of regulations that are thought through from the end: well-intentioned, but systemically problematic.
As the German Demolition Association, we therefore see it as our task to actively shape this debate—at a high level, with technical clarity, and with the goal of aligning safety, resource protection, and practical feasibility.
If we conduct this debate openly and professionally now, we lay the foundation for solutions that work not only today, but will also endure tomorrow.
Not everything that contains hazardous substances is dangerous—but everything we do demands responsibility.
Hazardous substances in the anthropogenic stock (in German) Download