Is there lead in steel?

A. Hi David. There are two issues to consider here. The first point, and you probably know it better than me, is that there is a little of everything in everything, and instrumentation improves every year. We will probably soon be able to detect all 92 natural elements in each item we examine :-)

But the second issue, with regards specifically to lead in steel: leaded steel is often used for machined parts -- the theory being that about 0.2% - 0.3% greatly improves machinability through lubrication and chip breaking. There is movement to try to replace the lead with other materials such as tin ("Pitt scientists get the lead out of machined steel", http://old.post-gazette.com/healthscience/19990719steel1.asp).

The overwhelming majority of steel, well over 90%, is free of lead. As we continue recycling of steel, however, it sounds like the lead would slowly but gradually build up, no? Say an automobile is 90% lead-free steel and 10% machined leaded steel with 0.25% lead, and it's melted down to build the next auto. The recycled steel would have 0.025% lead. 90% of the next auto would be built of that, and the other 10% would be of 0.25% leaded steel. When that is melted down, the recycled steel would be 0.0475%, asymptotically approaching 0.25% :-)

Regards,