Are smoke alarms hazardous to the environment?

Are smoke alarms hazardous to the environment?
Yes, they have radioactive elements and should be disposed of properly. They are terrifying to put in landfills. But not unsafe to you in your house.
"The most readily accessible and cheapest smoke alarms contain radioactive nuclear waste contained by the form of americium-241 which is a waste product from nuclear reactors.
Americium-241 is radioactive, an alpha emitter near a half natural life of 432 years. This means that it will verbs to be a hazard for several thousand years."
Not at adjectives.
what? Why?