Is the ponytail palm tree poisonous to cats?

My cat has been chewing on our ponytail palm during the last year, and now she has been diagnosed with chronic renal failure, even though she is only 7 years old. In searching the internet for My cat has been chewing on our ponytail palm for the last year or so. Now she has been diagnosed with chronic renal failure, even though she's only 7 years old. Two on-line lists say that plant is not toxic (www.scvec.com and www.sniksnak.com), but I am still looking for more information.