Silica Gel

[Achebe]

The package proclaims
“Winter Harvest,” evoking notions
of pristine snow, white
as the poisonous silica gel
like blanched roe
hidden underneath seaweed sheets
that are fragile as stained glass.

A red exclamation mark
and a dying child with mouth agape
warns in Korean, Japanese,
English, Chinese: Poison! Danger!
So, don't call it health food
when you bring death
so close to my lips.

So since you've figured out that silica gel isn't poisonous after you wrote the poem, I don't need to clarify that! 
You don't need to research it. It's silica.
So L4 and all of S2 don't make a lot of sense now