A:
Yes! Both cedar and pine shavings contain phenols, the oils in the wood that give them their fresh and woodsy smell.
Phenols are poisonous, caustic, acidic compounds present in soft woods, and are routinely diluted for use in disinfectants (such as Pine-Sol and Lysol) and cover the smell of animal urine. Because phenols are caustic, they constantly irritate the nasal passages, throat and lungs which gives an easy opening to bacteria.
Phenols affect the kidneys and liver, the organs responsible for filtering blood and urine and eliminating toxins from them. Long-term exposure to phenols can cause liver damage and make the animal very sensitive to anesthetics. Exposure to phenols can also depress the immune system, thus causing lowered resistance to diseases such as respiratory infection. Pine and cedar shavings are toxic to small animals and should not ever be used.