John Gerrish and Ellen Chung, their 1-year-old daughter, Miju, and Oski, the family’s golden retriever, were found dead on a remote hiking trail along the Merced River in the Sierra National Forest last month after a family friend reported them missing.
There were no signs of trauma or obvious causes of death, and autopsy toxicology tests are still pending.
But after receiving test results of high levels of toxic algae water samples downstream from where the family was found, the Bureau of Land Management on Friday blocked access to campgrounds and recreation areas along the lengthy section of river.
Signs warning about toxic algae were already posted along the Merced River when the family died.
“The public must not enter the closure area. All uses within the closure area are prohibited,” stated the BLM order.
“The safety of visitors to our BLM-managed public lands is a top priority,” BLM field manager Elizabeth Meyer-Shields said in a statement. “These algal blooms can produce toxins that can make people and pets extremely sick.”
Officials will “continue to monitor the algae’s presence and look forward to when the public can safely recreate in the Merced River,” she added.
The area will be closed at least until Sept. 17.
After the family’s bodies were found, the area was treated as a hazmat site and blocked off due to concerns about possible toxic gasses from an old mine in the area. But that was later discounted as a possible cause of death.