Tackling staining on our headstones – an update

Some of our headstones in cemeteries across France and Belgium have developed dark staining. These marks are not simply surface dirt, they’re caused by tiny photosynthetic and fungal organisms that thrive in all weather conditions. Some produce dark pigments that settle deep into the stone, making them hard to remove.

While older chemical-based cleaning products masked the problem and appeared effective in the short term, they did not prevent regrowth and may have made the stone more prone to future staining. Our current approach avoids harsh chemicals to better protect the stone, but it cannot fully remove the marks.

We are actively committed to finding an effective long term sustainable solution. We appreciate your patience as we work with scientists. Together we are determined to find the answer to this complex problem.

We would like to thank those who brought this important issue to our attention, helping us ensure we give it the attention it deserves.

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Further information – dark staining on headstones

The staining is caused by biological colonisation - a living microbial biofilm that includes green algae, lichens, and fungi (such as Cladosporium and Alternaria). These organisms grow in humid conditions and penetrate both the surface and subsurface of the stone.

Thanks to the efforts of our regional teams and reports from our supporters and visitors to our sites, we are aware that this issue is affecting around 100 of our sites in France and Belgium

We are conducting a full survey of our estate to get a true sense of the scale and potential cause of the issue.

Absolutely not. We're actually spending more than ever on solutions that meet our needs, are safe for our people, and respect the environment.

We continue to receive strong support from our Commonwealth member states and are staffed by a dedicated and skilled workforce. However, this issue is a unexpected challenge. We are actively working alongside scientific experts to develop an effective solution.

Our headstones are regularly cleaned, both seasonally and as needed. However, the recent growth we're seeing is different from what we've previously encountered, and our current cleaning methods are not fully effective against it.

We would like to emphasise that the challenges currently affecting some of our sites are not the result of neglect, under-resourcing, or a change in our long-standing commitment to sustainability. Rather, the withdrawal of chemicals, including biocides which are now prohibited in many countries around the world, combined with climatic changes in recent years, has made our operations increasingly challenging across parts of northern Europe, but we do maintain the same core aim of appropriate ‘care’ for all our cemeteries - that has not changed, nor will it.

Our previous cleaner was a biocidal product that masked biological growth using a chemical bleaching effect. While effective at masking the issue, it raised environmental concerns.

Our current product is chosen to be less harmful to the environment, but it is not as effective at removing the deep staining.

We are actively exploring and testing new treatment options, including sol-gel coating and oxygenated compound-based products

Some of these alternatives are already on trial at sites in France and are being reviewed for effectiveness and suitability for long-term use.