Under most circumstances, it is not illegal to kill bees. However, using certain federally prohibited compounds to kill bees is illegal. Killing bees is detrimental to the environment, and in an effort to protect the plants that rely on bee pollination, many states have enacted laws to protect bees.
Rumors are prevalent on the Internet that it is illegal to kill bees. This is not unilaterally true. Many, but not all, states have laws in place to protect bees. These laws do not necessarily make it illegal to kill bees, but they create other protections by protecting their habitats and create bee breeding programs.
TL;DR (Too Long; Didn't Read)
Although it is not outright illegal to kill a bee, it is illegal to use certain pesticides on bees or any other insect.
Regardless of the legality of killing bees, it should be remembered that bees are an indispensable part of our planet's ecology.
It is a misconception that it is strictly illegal to kill bees. It depends on the method used to kill the bee. Approaches such as swatting, using natural liquids or administering EPA-approved chemical solutions to kill a bee are not prohibited by law. The use of federally banned pesticides, however, is illegal.
Pollinator Protection Act
In 2008, the U.S. Senate and House of Representatives passed the Pollinator Protection Act after it was noted that honey bee populations were in decline. Since then, the federal government has taken additional steps to protect bee populations, like the 2014 establishment of the Pollinator Health Task Force and two bills introduced in 2015, the Saving America's Pollinators Act and the Highways, Bettering the Economy and Environment Pollinator Protection Act.
The terms of the Pollinator Protection Act promote research and study of honey bees and is intended to support the lifespan of these insects, which is integral to the earth's long-term welfare. There is no language, however, making it a federal law to kill bees.
Although it is not outright illegal to kill a bee, it is illegal to use certain pesticides on bees or any other insect. Federal courts have ruled pesticides that may severely harm entire bee populations, such as Movento and Ultor, illegal.
Killing bees may be hazardous to your health or potentially lethal should you have an allergic reaction to bee stings. The best method for bee removal or eradication is to contact your local pest control or bee swarm removal service.