Hi SD_Deb,
The only way to buy a mattress that has no fire retardant at all and hasn’t passed the fire regulations is if you have a doctors prescription and a manufacturer is willing to make one for you. I would keep in mind though that there are “safe” ways to pass the fire regulations using wool or an inherent viscose/silica fire barrier.
I don’t keep any records of the specific mattresses which the retailers in the various lists in the forum carry on their floor which is constantly changing and would be impossible for any single person to keep up with so I would always call and talk with any retailer or manufacturer you are considering visiting before you go there to tell them what you are looking for and to make sure carry some mattresses that meet your criteria.
You can see the details here.
Phoenix