COMMENT FROM DEBRA: Clearly this lab test shows that iron is leaching from cast iron skillets. This is not new information. It's been known as long as I've been writing--almost thirty years.

As to whether or not the iron that leaches from cast iron skillets is unhealthy, well, I think that depends on the person. Obviously cast iron cookware has been in use for a long time and as far as I know no illness is associated with it.

The only danger I see, and this is completely individual, is that the amount of iron leaching may be too much for an individual body. This would be the case if, say, all food eaten was cooked in cast iron and the individual's body had difficulty processing metals. But for a healthy person, it should be fine. Most people probably don't get enough iron in their diet, particularly women, but I wouldn't use a cast iron skillet as a dietary supplement.

COMMENT FROM DEBRA: Xtrema is not on this list. Their cookware is made from ceramic, which doesn't leach.

I'll grant you that soaking a pan in acid for 24 hours may not give much insight as to safety in cooking, but apparently that is the way this test is done.

The more I research this subject of leaching, the more I think I need to research it. I first became aware of stainless steel leaching years ago when I read a report from Rodale Press about how they tested water that had been distilled in a stainless steel distiller and found heavy metals in the product water. Unfortunately, I no longer have that reference, but it didn't have a copy of the actual lab test.

If I had the funds to do so, I would cook in all these different types of cookware and have the results analyzed.

There is an interesting blog post at Chowhound: Is Nickel Leaching out of my Stainless Steel Press Pot? in which the blogger says she got sick after drinking tea that sat overnight in her stainless steel press pot.

A comment from an industrial hygenist...

from the journal of biomedical materials research:

"Stainless steel and titanium alloys are the most common metallic orthopedic materials. ... Nickel ion leaching is correspondingly worse if the surface corrosion resistance deteriorates..... Immersion tests were carried out to investigate the extent of nickel leaching under simulated human body conditions.... The sample with surface TiN [titanium nitride] exhibits the highest amount of cell proliferation [good since you're talking about cells growing around the implant] whereas stainless steel fares the worst."

http://cat.inist.fr/?aModele=afficheN&cpsidt=18889002

these are from internet sources i'm not familiar with. but for what they're worth:

"Every cooking material will leach some metal into the food, especially under high temperatures. Acidic and alkaline foods will increase the leaching for certain types of cookware.... Stainless steel that has been cleaned and scoured with a metallic pad may also leach a small amount of nickel into the food, when exposed to alkaline food. If your food tastes metallic, you should consider changing your cookware."

http://www.school-for-champions.com/health/cooking_surfaces.htm

"For the record, in lab tests stainless steels do loose mass in the presence of certain food stuffs namely vinegar fumes and concentrated salt water solutions (watch out for ketchup). Some publications have noted that cows milk has a high level of nickel compared to other foods this may be due ubiquitous use of stainless steel containers to store bulk milk. More independently funded research into the amount of metals that leach into various foods from contact with stainless steel would provide more information."

http://www.finishing.com/307/01.shtml

I'm an industrial hygienist, so I pretty much sample people for things like heavy metals, hexavalent chromium, and mold for a living. So I speak in terms of TCLPs and 8RCRA and ASR and OSHA PELs, and I send people letters outlining their sampling results every day. It's unrelated, but I also have a well-developed nickel allergy. If anyone is interested, the austenitic structure of stainless steel is such that any scratch forms a passivation layer pretty quickly and leaching is highly unlikely after a matter of a minute, let alone two days of sitting after a scour. Even so, since chromium has greater motility and is present at a higher concentration than nickel it would actually be the more likely culprit.

There seems to be conflicting information on some materials. But Xtrema does not leach.

COMMENT FROM DEBRA: In Q&A: Cast Iron Skillets Made in China, I wrote about how some cast iron skillets are "seasoned" with paint, rather than the traditional method of using edible oil. I don't know about Martha's Cast Iron in particular, you should call the company and ask. The painted cast iron is FDA approved and so should not leach any metals or other harmful substances, but I'm not completely sure of it's safety. I would purchase cast iron that is not preseasoned, and season it myself.

COMMENT FROM DEBRA: I didn't perform the tests, but I am assuming the speckled metal bakeware is Graniteware. It is coated with a glassy enamel coating which apparently doesn't block leaching, according to this particular test.