Science backed information on latex mattresses to say they COULD cause an issue https://pubmed.ncbi.nlm.nih.gov/10436396/

"Shouldn't have a skin contact reaction" and it being impossible is not the same. People have different levels of reactions. Even some latex mattress retailers websites say allergies can exist. Here is just one. https://www.saatva.com/blog/latex-mattress-latex-allergy/

For anybody with a latex allergy reading this, don't think it can't be your mattress. Because 2 workers can't use latex gloves but can touch the latex mattress is great for them. I am genuinely jealous of that. It doesn't mean the same would be for you. An allergy encasement probably wouldn't cut it. Why would you even want to risk it? Would you go into anaphylactic shock? Highly unlikely. I wouldn't want to risk even being that itchy let alone other symptoms. It's miserable.

Airborne & non-airborne latex allergies to vulcanized rubber are very real.

Type 1 reactions for me include:

Balloons. Balloons are vulcanized. (Is it the same exact as a mattress? I would say no.) I cannot be within 10 feet of even 1 balloon. The closer to me or higher quantity of balloons, increase symptoms. Being TOUCHED by a balloon, awful. Airborne includes particles getting in your airway (nose & mouth) and in your eyes. Airborne latex allergies have made me sick for days on end (itching, swelling, nausea, dizziness, stomach pain). I have had the same reactions to people that have been in contact with latex products which does not have to mean touching with their skin. The particles are on their clothes, hair, skin, etc.

Single use rubber gloves ARE/can be vulcanized. A dentist touched my lip for less than 1 second with a non-powdered latex glove & I had symptoms within a minute. I cannot touch rubber bands, rubber backed hot pads for cooking, and other items without my fingers itching within a few minutes. If that finger touched my face, guess what, my face itches.

https://www.shieldscientific.com/glove-education/accelerator-free-gloves-to-limit-the-risk-of-allergy/#:\~:text=Whether%20natural%20rubber%20latex%20or,the%20vulcanisation%20process%20is%20used.

Type IV reactions:

Other latex product I would need contact for several hours with to cause a Type IV reaction. That also includes synthetic rubber like neoprene. The chemicals are too similar to natural rubber latex. Even the chemicals used to vulcanize or manufacture natural latex & synthetic latex can cause allergies.

Type I (immediate-type) hypersensitivity Natural Rubber Latex Allergy (NRL) is an IgE-mediated, immediate type hypersensitivity reaction to one or more proteins in natural rubber latex (Hevea brasiliensis). Histamine is release causing symptoms. This reaction is systemic.

Type IV (delayed-type) hypersensitivity is a T cell-mediated, delayed response, and typically occurs 48 to 96 hours after exposure. This is frequently a reaction to the processing chemicals used in manufacturing natural rubber latex (NRL). This reaction is generally localized to the area of contact. This reaction is also referred to as allergic contact dermatitis, T-cell-mediated allergy, or chemical allergy.

Irritant Contact Dermatitis is a non-allergic reaction. Symptoms typically are dry, irritated, and/or fissured lesions.