Angry Toxicologist

I still don't want to have to worry about keeping kids' mouths off KIDS' toys! And bibs! Of course there are justifications for lead paint, but outsourced children's products don't quite fit there.

Posted by: dietcoupon | August 16, 2007 11:31 AM

Yeah, but the reason lead-based paint is so "durable and beautiful" is -- recalling this from the last painting manual I read --- lead-based paint by design over the years sheds its surface layer.

A vinyl or latex paint doesn't get chalky and lose its surface, the material clings more effectively to itself and so accumulates a coating of grime and needs to be cleaned and repainted more often.

This 'chalking' feature is fine for the appearance of the painted surface - the paint just gets slightly thinner but stays clean and pretty.

Toxicology includes consideration of where materials go _after_ they are used as intended, in its range of concern, doesn't it?

Posted by: Hank Roberts | August 16, 2007 3:59 PM

Graculus, what's your basis for that opinion? I'd like to look at where it comes from.

These excerpts below are similar to the sources I'm recalling.

I'm not saying using this is a _good_ idea. I"m saying this should be understood when admiring _any_ lead paint: available lead does react with many things, such as sulfur, and mobilizes into the environment quite easily. All you need is soft water, or spit, or sweat.

Chalking of lead paint used to be an advantage; now it's an unavoidable problem. If the lead in paint were perfectly encapsulated, there'd be no reason to use it! Titanium's much better. Rainwater with sulfur in it, kids' saliva, or just dust from wear and tear, lead doesn't hold still --- it moves.

"Prior to about 1940, paint typically contained high amounts of lead -- often 10 percent and sometimes as high as 50 percent...." http://www.nhi.org/online/issues/95/lead.html

"Chalking paint was a way of having a self cleaning building. The top surface of the paint gradually turns to a fine powder, which gets washed away with the rain leaving a cleaner outer appearance. But the chalky effect is not as desirable today as it use to be and most paint available is anti chalking, even so most exterior oil based paints will eventually chalk to a certain degree."
http://paintingyourhouse.info/exterior_paint.htm

This has been known for a long while.

This observation quoted below is from a letter listing many well known health problems associated with lead use, by an author you'd have thought the paint industry might have paid attention to:

"... In America I have often observed that on the Roofs of our shingled Houses where Moss is apt to grow in northern Exposures, if there be any thing on the Roof painted with white lead, such as Balusters, or Frames of dormant Windows, &c. there is constantly a streak on the Shingles from such Paint down to the Eaves, on which no Moss will grow, but the Wood remains constantly clean & free from it....
...
"This, my dear friend, is all I can at present recollect on the Subject. You will see by it, that the Opinion of this mischievous Effect from Lead, is at least above Sixty Years old; and you will observe with Concern how long a useful Truth may be known, and exist, before it is generally receiv'd and practis'd on."
-- Benjamin Franklin, Philadelphia, July 31, 1786 (letter to Benjamin Vaughan)
http://www.phillyfuture.org/node/5557

I'm just saying, with all this stuff --- toxicology focuses on immediate harm from direct application.

But lead bioaccumulates, like so many other problems -- humans dig it up and spread it around, it goes out into the world, and then returns to concentrate again, in the food chain, and we're the top of that.

On a hopeful note, I see more and more mention of using microarrays in toxicology, collecting the information about exactly which genes are involved in toxic reactions to chemicals.

That, it seems to me, is finally going to blow the bullshit artists out of the political arena.

I'd say, watch for test cases being set up to try to convince the courts that microarray testing can't be relied on as a way to say for sure what's too dangerous to allow in commerce. Yes, they do that kind of thing, try to cut off any new promising scientific approach that will damage a market by exposing its externalized costs.

Posted by: Hank Roberts | August 22, 2007 2:11 AM

Equipment manufacturers use lead paint because it sticks. I don't know why anyone would use it for a residential dwelling. It's a mess to clean up, and water-based paint sticks just as well to wood and drywall. We discuss stuff like this at http://www.envirofreak.com. Manufacturers in the USA are bound to environmental regulations that keeps them, for the most part, clean. That is why they go to Mexico and China. I went to a trailer manufacturer once (Hyundai) to teach them how to wire their trailers with a new product we had. They built their trailers in Mexico because there are fewer regulations. An AQMD inspector in Californi would have had a cow if he saw what I did that day. They were spray painting the trailers outdoors on the lot where they were built. I couldn't even breathe -- the toxic fumes were THAT BAD!

Posted by: Chris Plante | August 24, 2007 6:22 PM

what about the paints that are used in houses? any explanation to that?

Posted by: painting in Washington | June 30, 2008 12:21 PM