Researchers at the U.S. Geological Survey stated that ash from the recent California wildfires might lead to serious health problems for local residents and environmental damages.

The researchers collected samples from two residential areas burned by the Grass Valley and Harris wildfires as well as 26 other sites. The study indicated the presence of caustic alkali materials in the ash, which can contain somewhat levels of metals such as arsenic, lead, zinc and copper.

“The study results also indicate that rainwater runoff from burned areas may adversely affect ecosystems and the quality of surface drinking water supplies,” said Deborah Martin, A USCS wildfire ash specialist and co-author of the study.

"These findings are consistent with the scientific knowledge about wildfire ash that has led counties in California to issue advisories regarding appropriate precautionary measures to avoid health problems associated with exposure to the ash," said Geoffrey Plumlee, a USGS lead author of the study.

Specialists have been issuing warnings and instructions about how to avoid exposure to these things. People were advised to use appropriate respiratory protection, gloves, long-sleeved shirts and long pants, dust mitigation measures and to wash the skin contacted by the ash.

The study has also shown environmental damage from rainfall runoff.

"The study results also indicate that rainwater runoff from burned areas may adversely affect ecosystems and the quality of surface drinking water supplies," said Martin.

The USGS recommends additional studies in burned residential area "to fully examine the potential environmental and health issues associated with residential ash and burned soils."

Local residents worried about exposure to the ash should contact their legal governments for information on preventive and protective measures that can be taken and for the risk level in their area.