A new study from Tel Aviv University (TAU) overturns prevailing scientific beliefs that King Solomon’s Mines not only harmed the health of workers in the ancient copper industry but also poses risks to the health of modern residents living near the site.

In the new study, researchers conducted geochemical surveys at copper production sites in the Timna Valley, dating back to the 10th century BCE and the era of the Biblical Kings David and Solomon. They found that the environmental pollution resulting from copper production was minimal and locally restricted, posing no danger to the region’s inhabitants either in the past or today.

TAU’s archaeologists also reviewed previous studies and found no evidence that the ancient copper industry polluted the planet.

The study was led by Professor Erez Ben-Yosef, Dr. Omri Yagel, Willy Ondricek, and Dr. Aaron Greener from the Jacob M. Alkow Department of Archaeology and Ancient Near Eastern Cultures, Chaim Rosenberg School of Jewish Studies and Archaeology, at TAU. The paper was published on November 29, 2024, in the journal Scientific Reports.

“We inspected two major copper production sites in the Timna Valley, one from the Iron Age and King Solomon’s era and another nearby that is about 1,500 years older,” says Professor Ben-Yosef. “We took hundreds of soil samples from both sites for chemical analyses, creating high-resolution maps of heavy metal presence in the region.

“We found that pollution levels at the Timna copper mining sites are extremely low and confined to the locations of the ancient smelting furnaces. For instance, the concentration of lead — the primary pollutant in metal industries — drops to less than 200 parts per million just a few meters from the furnace. By comparison, the U.S. Environmental Protection Agency defines industrial areas as safe for workers at 1,200 parts per million and residential areas as safe for children at 200 parts per million.”

The new study contradicts a series of papers published since the 1990s about pollution caused allegedly by the ancient copper industry. “We demonstrate that this is not true,” Professor Ben-Yosef says. “Pollution in Timna is very restricted spatially, and it’s likely that only those working directly at the furnace suffered from inhaling toxic fumes. Just a short distance away, the soil is entirely safe.

“Moreover, the match we found between the spatial distribution of copper and lead concentrations in the soil further indicates that the metals are ‘trapped’ in slag and other industrial waste, which keeps them from leaching into the soil and affecting plants or humans.”

In addition to the geochemical survey, the TAU archaeologists also conducted a comprehensive review of existing literature, pointing out that hypotheses about global pollution during the pre-Roman period lack solid evidence.

“As researchers confronting the severe environmental challenges of our time, such as climate change, we often tend to search for similar problems in the past or assume that environmental harm has been an inevitable consequence of human activity since the agricultural revolution,” Dr. Yagel says. “However, we must be cautious. While we might label a few pieces of slag on the ground as ‘pollution,’ we should not confuse this localized waste with regional or global environmental pollution.”