Picture a worker in a metal-plating workshop or a welding area, surrounded by metal parts, fumes, or chemical baths. In some workplaces, one of the substances workers may come into contact with is chromium.
Chromium can be useful in industry — for example to protect metals against corrosion or to create hard, shiny surfaces. But not all forms of chromium are the same. Hexavalent chromium, also known as Cr(VI), is a particularly harmful form. Repeated exposure can irritate the skin and airways and, over time, increase the risk of serious diseases such as lung cancer.
“Knowing that someone has been exposed is not always the same as knowing how their body is responding.” – Jelle Verdonck
That is why chromium exposure is monitored through workplace measurements, biological monitoring, and safety limits. Yet knowing that someone has been exposed is not always the same as knowing how their body is responding.
Recent research is therefore moving beyond simply measuring exposure. In a European study on workers exposed to hexavalent chromium, scientists examined blood samples for epigenetic markers: chemical marks that help regulate how DNA is read, including DNA methylation and hydroxymethylation.
These measurements are not meant to diagnose disease in individual workers. Instead, they help researchers understand whether the body is already responding to occupational exposure, and whether extra protection may be needed earlier.
When Genes Change Their Activity
Exposure does not always lead to immediate symptoms. A person can feel healthy while their body is already reacting at the molecular level. These early changes are not necessarily changes in the DNA sequence itself: the genetic code usually remains the same. What can change is the way DNA is read by the body, for example when making proteins.
“Environmental factors, such as exposure to chemicals, can influence which genes are switched on or off.” – Jelle Verdonck
This system can be compared to a book: the text stays the same, but some chapters are opened more often, while others are used less frequently. Environmental factors, such as exposure to chemicals, can influence which genes are switched on or off. In this comparison, some genes become like bookmarked chapters: easier to find and used more often.
This is why researchers are studying the mechanisms that help determine when genes are switched on or off. This study of gene regulation is called epigenetics. Some epigenetic changes may even be passed down to subsequent generations. But interpreting these signals is not simple. The body also responds to food, stress, sleep, infections, and many other environmental factors. Not every change in gene activity means that someone will become ill.
Early Warning Signals for Prevention
The challenge is to identify which biological signals are meaningful, reliable, and useful for prevention. If specific changes can be clearly linked to harmful exposure, they may one day serve as early warning markers. These markers would not diagnose disease, but they could show when closer monitoring or preventive action is needed.
Read this article to learn how pollution is leading to plastic in people’s brains!
For workers in high-risk environments, early biological warning markers could add an extra layer of protection by showing whether the body is already responding to hazardous exposure, long before symptoms appear.
The main promise of this research lies in prevention. By listening to these early biological signals, scientists may help shift occupational health from reacting to illness toward preventing it. More research is still needed, but the direction is clear: our bodies may already be telling us something long before we feel it. Science is learning how to listen.