A fourfold increase in fentanyl-related overdose deaths in the last two weeks has Marin County health officials sending out a health advisory. In the last 14 days alone Marin County has seen five overdose deaths related to fentanyl. The county sent out an alert to local doctors and to providers who offer assistance to people who abuse drugs. The health advisory says since February 14th it’s suspected the victims ingested fentanyl in combination with methamphetamine. According to the county, substances in wastewater have also increased as have emergency calls for non-fatal overdoses. According to the health department, the increase may be due to increased concentration and intentional use of fentanyl or increased contamination of fentanyl in other substances. Drug overdoses are the leading cause of death in people under 55 in Marin County.