To be precise, many of widely-used batteries are not hazardous, such as zinc carbon and zinc chloride batteries. Therefore using these batteries and handling them with bare hands is safe.
Some batteries contain hazardous materials, but they are sealed inside and unlikely to get touched in daily usage. Actually they do need to be treated more carefully, e.g., Lithium batteries should be kept away from heat sources to avoid catching fire or explosion. 
This changes when it comes to disposal. The sealing could be punctured or corroded, releasing the hazardous materials such as mercury and lead into the environment if we just mix them with other rubbish. You can consider this as dealing with a mercury thermometer: there is something hazardous inside, but we can still use it normally with some extra cautions. However, leaving it to be broken in a random place is never a good idea.
spam fails_task lang_mismatch pii not_appropriate hate_speech sexual_content quality toxicity humor helpfulness creativity violence