Here's the MSDS. Notice that it says it does not require gloves, but does recommend eye protection.
I'm looking at the label and I don't see where it calls for gloves -- though it's possible this product is slightly different from what you've got.
The product label tells you what's in it:
This product is formulated from 80-90% horticultural-grade sphagnum
peat, perlite, fertilizer and a wetting agent.
Since it is a fertilizer product, they are required by many (most?) jurisdictions to list the N-P-K content:
Seed Starting Potting Mix, 0.05-0.01-0.05
Guaranteed Analysis
- Total nitrogen (N) . . 0.05%
- 0.005% ammoniacal nitrogen
- 0.035% nitrate nitrogen
- 0.010% urea nitrogen
- Available phosphate (P2O5) . . 0.01%
- Soluble potash (K2O) . . 0.05%
Derived from: urea, ammonium phosphate, and potassium nitrate.
The only mystery ingredient in there to me is the "wetting agent".
The peat and perlite are pretty harmless (just don't inhale). I'm no safety expert, but the fertilizer is at such a low concentration that it doesn't seem like it could do much harm.
I mix my own potting / seed-starting soil with higher fertilizer content, sometimes with peat and/or perlite as ingredients, and I've never had any problems handling it with bare hands. The only reason I sometimes shy away from letting the kids dive in bare handed is because their hands often end up in their mouths, and that just doesn't seem like a good idea.