Model calls for action in airline dog death

>>> is on a mission today to raise awareness after her beloved golden retriever died on a cross-country flight. she says united airlines is to blame, but the air carrier claims that just isn't true. the story now from nbc's michelle franzen .

>> reporter: supermodel maggie rizer has graced the cover of fashion magazines like "vogue" and the catwalk for designers worldwide. after starting a family complete with dogs brea and albert, rizer began blogging about her life. she's been writing and talking about her emotional loss of brea who died this month onboard a cross-country united flight. rizer claims the airline didn't do enough to protect her pet from the heat when she says the plane sat on the tarmac with the engines off. she also says when the family arrived in san francisco , workers could not explain what had happened.

>> i was hysterically crying. i didn't know if they had let her out and she had been run over by a plane. i didn't know if she fell out of the plane while they were boarding her, if her kennel fell off. i didn't know if they let her out and she boiled to death.

>> reporter: rizer's two dogs were stored in the cargo area along with other pets. the heat died of heat stroke , and the dog was in good health. a veterinarian who also reviewed the case says other factors may have also played a role.

>> i think it's possible that all the dogs were experiencing heat stroke , but not all the dogs got sick. bea vomited which can happen with heat stroke but it's not necessarily one of the more common things that you see.

>> reporter: in a statement united says the safety of our animals is always considered first and foremost when making decisions regarding their routing and carriage. united also offered condolences to the rizer family for their loss but said after careful review, we found there were no mechanical or operational issues with bea's flight and also determined she was in a temperature controlled environment for her entire journey. rizer has not sued the airline but instead is trying to raise awareness by sharing her story and hopefully, she says, improve how pets are cared for on flights.

>> something dramatic needs to be done because this is just going to keep happening.

>> reporter: for "today," michelle franzen , nbc