Nikon D6 Reference Manual page 48

A WARNING (CR1616 Lithium Watch Batteries)
Keep batteries out of reach of children.
Should a child swallow a battery, seek immediate medical attention.
Do not immerse batteries in water or expose to rain.
Failure to observe this precaution could result in fire or product
malfunction. Immediately dry the product with a towel or similar object
should it become wet.
Discontinue use immediately should you notice any changes in the
battery, such as discoloration or deformation.
Failure to observe this precaution could result in the battery leaking,
overheating, rupturing, or catching fire.
Insert the battery in the correct orientation.
Failure to observe this precaution could result in the battery leaking,
overheating, rupturing, or catching fire.
When batteries are no longer needed, insulate the terminals with
tape.
Overheating, rupture, or fire may result should metal objects come into
contact with the terminals.
If battery liquid comes into contact with a person's skin or clothing,
immediately rinse the affected area with plenty of clean water.
Failure to observe this precaution could result in skin irritation.
xlviii For Your Safety