Rust ( Ferrous Oxide ) is not going to do any harm and eventually might be good providing some iron (Fe) needed. Rebars and CRW all do rust and they are used in gardens as stake and cages everywhere. You might want to ware gloves while handling them.

Sey.

Probably the smelly residue was some oil to prevent rust, since I've never noticed the CRW and rebar I use (and I used a lot of both lately) to have any odor. So it depends where they got the oil if that was done, and what type of oil it was. It's unlikely it will make any difference.

Here in FL where it gets hot and humid, CRW does kill and damage leaves that get stuck against it. I'm pretty sure it is for both reasons, the heat of the metal and the rust residue that the leaf rubs off in the rain (and wind) on to itself, rain evaporates, and residue can burn the leaf. Each plant has a couple of leaves like this but it is not a problem in general, just something that is is a small drawback. It happens every once in a while with the rebar too, but is more rare. A fruit pressing against either can get damaged fr the same reason as it matures, but it happens to very few and you can put something to protect or lift them if you want.

About the soil, oil is not a great idea, and though I doubt it is used motor oil, I guess that depends who you got it from as I've known people to use that and it wouldn't be bright. Can't imagine a retailer using it, but you never know ... I wouldn't have bought oily metal if I found it. I don't think it will be a permanent problem though and most clean oil is pretty safe; some mineral oils are used as a safe pesticide to spray plants.

Cheers

PC

Agree with the above. The only problem I can foresee is that manufactures might apply a thin coating of oil to prevent rusting before the rebar is sold. I have no idea what type of oil they use though.

It's slightly off subject, but some people put used motor oil on shovels and other garden tools as a protectant, but I wouldn't. I think that if someone wants that protection, used cooking oil would be better - maybe even WD-40.

I doubt you have any reason to use heavy metals, but iron is very safe. It is possible, although not likely, that an iron buildup could cause a nutrient conflict, but it would be very rare and I've never heard of it happening. Stainless steel and galvanized shouldn't cause any trouble.

Copper can have both good and bad effects on humans, so I would keep it to specific purposes.

Aluminum will oxidize slightly, but it too is a nutrient in small amounts. Since it is fairly resistant to oxidation, I doubt it would ever be a problem.

In short, while I wouldn't be quick to put anything made with lead in the garden, none of the common metals should cause an issue.

<I've heard about not using pressure-treated lumber because of the chemicals which could leach into the soil. >

That ceased to be an issue in 2002 when the chemical process was changed for sales to the public and the arsenic removed except for in commercial construction/contractor sales. Plus even then the leaching was minimal and only a 2-4" gap required.

As for the metals issue - minimal, if any, issue as the others above have said as the elements are naturally found in the soil.

Dave

PS: the coating used on most rebar is a sprayed on combo of epoxy and dry powdered calcium - thus the grey residue.