agggghhhhhhhhhhhhhhhhhh ... the sky is falling, the sky is falling!
;-)
People who manufacture these metallic salts recieve long-term exposure. And what they do _is_ fraught with hazard. In fact, they wear much the same protective garb as folks who process mineral oil.
However, users of salad bowls are not manufacturers of metallic salts and do not recieve 'long term exposure'. They recieve 'intermittant / sporadic' exposure at extremely low levels. Different animal altogether. That was a carefully worded advertising blurb trying to sell you on the negligible advantages of using their product over some other. Not too different from selling 'high-fiber' foods from a processing plant located next door to a sawmill.
So how many salads are _you_ planning to eat?
Enough to exceed the Permissable Exposure Limit (PEL) on a regular basis? I rather doubt that. I don't think you could even approach the PEL for those salts if you threw away the salad and actually ate the bowl.
Here are some numbers for cobalt from the National Safety Council.
"People who work in the coal mining and hard metal industry, cobalt dye painters in porcelain factories, and workers in the ore processing and chemical manufacturing industries may be exposed to cobalt inhalation at higher than background levels."
Exposure Values:
- IDLH: 20 mg/m3 (as Co) (NIOSH, 1997 * NIOSH REL: TWA 0.05 mg/m3 * OSHA PEL: 0.1 mg/m3 formatting linkcobalt is a constituent of vitamin B-12)
and for manganese: Exposure Values:
- IDLH: 500 mg/m3 (NIOSH, 1997) * NIOSH REL: TWA 1 mg/m3 ST 3 mg/m3 * OSHA PEL: C 5 mg/m3 [*Note: Also see specific listings for Manganese cyclopentadienyl tricarbonyl and Methyl cyclopentadienyl manganese tricarbonyl.] formatting linkthat the NIOSH REL is a Time Weighted Average (TWA) based on 10 hours per day / 40 hours per week.
Oft-recommended mineral oil also has both a PEL and an LD50. Do a Google search for yourself if you don't want to accept this posting from OSHA.
"All finishes are non-toxic when fully cured, despite what you may have read or heard. Once the solvents are evaporated, the cured film is safe enough for contact with food. This does not mean that the finish itself is safe to gobble up. It means that additives such as driers or plasticizers are encapsulated enough so that they do not migrate to what you?re eating. For edible finishes, wax and shellac are the only ones I?m aware of (which is why apples and candy are coated with these)"
You probably don't want to know where antifreeze ends up ... read any good candy bar wrappers lately?
Here's the gig, as I see it. The US gubmint says BLO is non-toxic if allowed to cure first. Reasoning on this by doing the rough math, I see that metallic salt ingredients that were most likely in the ppm range (Too low, in fact, to require protective labeling or even inclusion on the label at all.) in the original container are reduced to the parts per billion range on my salad (a few millionths, by weight, of a microgram of finish on a comparatively huge chunk of tomato) and in the parts per trillion (or even more dilute) range when I put the fork in my mouth.
Since I suspect that I get a larger and more frequent dose of heavy metals than that just by breathing, I'm willing to risk eating as much of that salad as you care to buy.
But, not from McDonalds. I, personally, think the risk is higher when you serve that salad from a plastic bowl ... off-gassing and plastic shreds, you know. And who knows what risks you face serving it from a colored glass bowl?
Once it's cured, it's safe. Anything else is unsupported by fact.
I must most respectfully disagree with you. Bill