While in the army I was at a weapons site and were required to test our mask seals with banana oil. It seemed to be the standard fielf test at the time, circa 1979-1982.
Old Timer

OH heck yeah… a neoprene diver’s hood would be hot too. Winter time, maybe not so much but warm weather heck yeah its going to get hot.

“Stay away from old Warsaw Pact filters.”

I’ve seen a couple of ‘Urban Explorer’ YouTube videos with titles like “We found a cold-war bunker with EVERYTHING inside!”

…only to discover once I watched them to be thoroughly looted except for one item – Those Warsaw-pact gas masks in large heaps….

….

(signed)
A veteran of a semi-successful pre-Gulf War attempt to change the filters on an M17 gas mask

Not that I’ve been able to find. When OSHA changed the silica dust standards we had to start wearing masks for some tasks at work. Our contract did not allow them to force us to shave so they got 3M PAPRs for some of us. You can find them on Amazon for about a grand (or more). They are just N100 HEPA filters though so won’t work against CS gas but someone probably makes ones that take standard filters.

Against a HAZMAT spill, it may or may not work. For HAZMAT preparedness, you can get a respirator that will provide solid protection. Broad spectrum cartridges are pricier, but they are likely cheaper than a gas mask. I’m a big fan of 3M’s respirators. (one plus side – you can use the same mask with cheaper OV/P100 cartridges for spray-painting or other work with lots of solvent vapors.) If you get one, make sure it fits well and seals to your face. If you cover the exhalation valve and exhale, the respirator should puff out, if you inhale while covering the cartridge inlets, the mask should be pulled in by the suction. While wearing the mask & cartridges, you should not be able to smell air freshener sprayed outside of the mask.

Since people already covered beards, I’ll mention eyeglasses. You need a special glasses kit to wear glasses under a mask, otherwise the side legs / temples will break the seal

You can get a PAPR (powered air-purifying respirator) that relies on positive air pressure instead of a tight seal. They have a variety of cartridges, and are very easy to breathe in. They are very expensive, and require batteries with chargers, however, so keep that in mind.

“Point of curiosity: short of a complete hood / suit, are there any gas masks that work if you have a full beard? ”

Not really, your best bet would be an SCBA pack, like what firemen wear, a pony bottle of breathable air/oxygen and a full face mask that stays at a positive pressure from the gas bottle, so a perfect seal isn’t required.

That gives you 20-30 min to escape wherever you are at.

Do you really foresee such a need in central Texas, where yo can shoot back???

Good points, but to me the idea of wearing a neoprene hood on my head in the Texas heat is enough to make that a nonstarter.

Someone else suggested that there is way to retrofit a full face negative pressure respirator, so that instead of screwing a filter cartridge onto the mask, you screw on a hose that runs to a belt mounted PAPR pump (to which you attach the filter cartridge), turning it into a positive pressure system. Additional benefit is that because you’re getting a constant flow of forced filtered air, it’s cooler and the mask doesn’t fog as easily.

I see that surplus battery powered, belt mounted PAPR pumps can be had on eBay for under $100. As I already have a full face respirator, that might be a solution (for PPE, not for combat).

The neoprene diver’s hood in concept sounds like a good idea but in practical use its not really such a good idea. The problem is the material and although a synthetic rubber it does not have all the qualities of actual rubber, it may be water proof but its not really chemical or chemical agent proof so, for example, a chemical agent in liquid form (or a ‘gas’/fog that will condense on surfaces) can actually permeate the neoprene along its sub surface (just below the material surface) leading to ‘leaks’ (by capillary action) into the face area under the mask even though the mask seems sealed against the neoprene. If you are going to be protecting against ‘fogging’ (which is really an aerosol form) types of ‘chemical’ agents (e.g. high density tear gas, or more insidious nerve/blister/choking and biological agents), or chemical spill type gasses, especially longer term exposure, you do not want to use the neoprene diver’s hood method.