SAN FRANCISCO (AP) -- Federal officials closed a portion of trails at a national forest in Northern California where a family and their dog mysteriously died last month, citing pending toxicology reports on nearby water and plants.
There was no clear cause of death, prompting authorities to treat the area as a hazmat scene.
The San Francisco Chronicle reported Tuesday that the area north of Fresno in the Sierra National Forest will be closed until Sept. 26.
Rangers can reopen the trails if conditions change.
Authorities have not yet determined how the couple, their 1-year-old daughter and their dog, died.
Investigators are considering whether toxic algae blooms or other hazards may have contributed to the deaths.