Welcome aboard
@hui!
Questions about toxicity come up from time to time, and one thing in these discussions is always the same: there's no easy yes/no answer.
When it comes to toxicity, a few things are important to understand before trying to figure out an answer:
* What kind of effects/risks are you concerned with (e.g. acute toxicity of a single exposure event vs long-term health risks due to prolonged exposure)
* What organisms/biological systems do you want to assess the impact on? Risks for humans vs. aquatic ecosystems are quite different.
* What kind of exposure scenario are you taking into consideration (e.g. normal use in a darkroom setting, waste resulting from normal use, exposure to organisms during the lifetime of the object you make, and/or inadvertent use such as pets or kids eating emulsion etc.)
I'll assume for now that your primary concern is with normal/intended use of these emulsions during printmaking in your darkroom, that you want to assess the risks to you as a printer/user and that you're concerned about immediate toxicity as well as long-term exposure risks.
With regular use and sensible safety measures, these liquid emulsion products do not offer any noteworthy health risk - none of them. They do not emanate toxic gases and even if you get some of the emulsion on your skin, the worst that may happen is some rather persistent (but harmless) silver stains that will erode away over the course of a couple of days. Once processed (exposed, developed & fixed), what remains is just a layer gelatin with finely divided silver in it, like any regular photographic print. This also poses no risk of toxicity to people who will handle your prints/objects.
Any risks of these liquid emulsions will stem from inadvertent use/abuse or careless handling. You don't want to get this stuff in your eyes, and you shouldn't eat it. So don't splatter it around and don't put it in your mouth. Wear gloves to prevent stains, although that's more of an aesthetic consideration (stains) than one of personal safety. Keep the liquid emulsion away from pets or kids; I've never heard of them wanting to eat it, but obviously you want to prevent this. Don't discard large amounts of unused liquid emulsion into wastewater flows (e.g. your sink); firstly; the gelatin may cause severe problems with clogging, and the silver salts are indeed toxic to aquatic life.
As you can read in the SDS you linked to, the main 'toxins' in these emulsions are the image-forming silver salts. After processing, these are converted in either metallic silver that's part of the image, which is essentially harmless, or in silver-thiosulfate complexes (the unexposed and fixed-out parts of your image). Used fixer should be considered toxic waste and disposed of through the local channels intended for this; in developed countries, there are solid waste management systems in place for this. Reach out to your municipality and/or government websites for questions about this. Other than the environmental aspect, used fixer is not a major concern unless you drink it, get it in your eyes etc. The same goes for used B&W developer, which in fact is even less harmful since the substances of concern tend to oxidize quite readily into less reactive molecules.
So to cut a long story short, as long as you use these materials sensibly and adhere to the (mild/limited) safety measures recommended by their manufacturers, there's no concern.
Have fun printing!