Those anti-caking additives in salt (like E 535) don’t damage DNA or cause cancer, according to lab tests and long-term rat studies, so they’re considered safe to eat.

What we've found so far suggests that ferrocyanides (E 535–538), which are used as anti-caking agents in foods like salt, do not cause DNA damage or cancer based on the available evidence. Our current analysis is based on limited data, but what we’ve reviewed points in a consistent direction. We analyzed one assertion supported by two studies, both of which indicate that ferrocyanides do not damage DNA or lead to cancer when tested in lab settings and in long-term rat studies [1]. These findings are the only evidence we’ve reviewed so far on this topic. No studies in our analysis have challenged this outcome. It’s important to note that our understanding is based on a small body of evidence. While the current data we’ve examined support the safety of these additives in relation to cancer and DNA damage, we can’t rule out the need for further research. We don’t yet have human trials or long-term population studies in our review, so our view remains incomplete. The evidence we've reviewed leans toward these additives not posing a risk for DNA damage or cancer under the conditions tested. However, because we’re working with limited data, we can't say how this holds up across different diets, exposure levels, or in sensitive populations. Practical takeaway: Based on what we’ve seen so far, the ferrocyanides used in table salt and similar products don’t appear to damage DNA or cause cancer in the tested contexts. We’ll update our analysis as more evidence becomes available.