Good news... you can shop for your milk w/o worrying about BPA!!! I contacted both Organic Valley and Horizon regarding their milk cartons and what they use as the lining... I am waiting to hear back from Horizon, but here is the response from Organic Valley!! PHEW!
Thank you for contacting us at Organic Valley. No, we do not use BPA in the lining of our milk cartons. The plasticused is either #2 or #3 depending on the carton. I hope this provides you with the information that you requested. Do nothesitate to contact me if you require additional assistance.
Organic Valley/ Cropp Cooperative