Urinary D-aminolevulinic acid in workers exposed to lead.

One hundred and fifty-five urine samples from workers in car painting, motor-bicycle or tricycle drivers, and printers were quantitatively analysed for delta-aminolevulinic acid. The levels were 0.86 + 0.32, 0.8 + 0.23 and 0.76 + 0.24 mg/dl, which were increased beyond normal levels by 63, 90 and 84 percent of the three respective worker groups.