Toxic Mushrooms Pose Danger in Fremont's East Bay Regional Parks

• Two mushrooms that can kill people and pets grow in East Bay Regional Parks: death cap and western destroying angel.
• Immediate medical care is needed to prevent liver and kidney failure.
• Avoid touching mushrooms, and watch your dogs to make sure they do not eat them.

FREMONT, CA — With abundant recent rains, wild mushrooms are emerging throughout East Bay Regional Parks, bringing both beauty and potential danger, including here in Fremont. Among them are the death cap (Amanita phalloides) and western destroying angel (Amanita ocreata), two of the world’s most toxic mushrooms.

Park officials are urging visitors and pet owners to exercise caution, as these mushrooms contain deadly toxins.

Both species produce amatoxins, which can be fatal if ingested. Symptoms of poisoning, which may not appear for up to 12 hours, often begin with severe gastrointestinal distress before progressing to liver and kidney failure.

Immediate medical attention is critical for both humans and animals who may have consumed a toxic mushroom.

“These mushrooms can be lethal to both humans and pets,” the East Bay Regional Park District warned. Pet owners should seek veterinary care if they suspect their animals have eaten a toxic mushroom. The mushrooms grow primarily near oak trees, appearing anywhere oak roots are present. To protect visitors, the collection of any mushrooms in Regional Parks is strictly prohibited.

To stay safe, park officials advise visitors to avoid touching or consuming any mushrooms and to learn how to recognize toxic species.

The death cap, introduced to California from Europe, has a greenish-gray cap, white gills, a white ring around the stem, and a large white sac at its base.

The western destroying angel, a native species, has a creamy white cap, white gills, and a thin white sac at its base.

While these two mushrooms are responsible for most mushroom poisonings in California, other toxic species, including Galerina and Lepiota, are also present in the Bay Area.

Park visitors are encouraged to stay informed and review safety guidelines.

Fremont's East Bay Regional Parks

There are multiple East Bay Regional Parks in or near Fremont.

• Ardenwood Historic Farm
• Coyote Hills Regional Park
• Dumbarton Quarry Campground on the Bay
• Mission Peak Regional Preserve
• Ohlone Wilderness Regional Preserve
• Quarry Lakes Regional Recreation Area
• Vargas Plateau Regional Park