Might be a "drano bomb":

http://www.youtube.com/watch?v=YbaiCdX1XWc

I think putting baking soda and vinegar into a bottle and then closing it. Coke and menthos is also a possibility, but the article speaks about 'household chemicals', not candy and fizzy drink...

A sensationalist tabloid in the UK might well call candy ( sweets UK) and fizzy drinks "house hold chemicals" to ramp up the "evil" factor.

Frankly I am please to see the word "terror" hasn't been weaved in just yet.