Hi donlbe,
Latex Green makes Dunlop latex cores that are very high quality and are a common choice for the Dunlop latex used by many high quality latex mattress manufacturers including several of the manufacturers that are members of this site. They are also one of three Dunlop manufacturers that also makes latex cores that are also certified organic (see post #2 here).
You can see their current Oeko-Tex certification here.
While the Latex Green cores themselves don’t contain fire retardants … the mattresses that use them do need to pass the fire regulations (CFR 16 part 1632 and part 1633) to be sold without a prescription in the US so the manufacturer would have some type of fire barrier in the mattress. I don’t know the specifics of the mattress you are looking at but there is more about different types of “safe” fire barriers in this article and in post #2 here and more about fire barriers and “safe” materials in general in post #4 here.
Phoenix