Is weed killer corrosive

I had a first hand experience of it (westland weed and moss killer). Yes it is corrosive if it contains sulpher or phosphorus or urea. I had a problem with weed killer in our home where weedkiller started to seep through its box (probably weed killer is hydroscopic). Within 3 months it had eaten away gas pipe which was next to it and we had a gas leak. Note that gas pipe was copper so it corroded even copper which is usually better corrosion resistant then carbon steel.

Hope it helps.

Asif