According to the fifth edition of American Honey Plants by Frank Pellett
(1976):
 
"The death camas is a plant of the lily family common to wet meadows
from Montana and British Columbia to California.  It is reported as the
cause of death of large numbers of honeybees during its period of bloom,
in the Minidoka project in Utah.  The bees die in the hives after their
return from the fields for honey, sometimes in alarming numbers.  The
plant is often reported as poisonous to cattle and sheep, occasionally
causing death."