Yes batteries are a hazardous waste and should be disposed of at a facility that can process them. As long as the battery is not leaking or swallowed, it is not dangerous. Logitech doesn't want you to replace the battery, they want your warranty to expire so you're forced to buy a new keyboard. This tactic is known as planned obsolescence. I replaced my original battery with a ML 2032 rechargeable from ebay ($7)for the K750 keyboard and so far so good(day 1).