Are Coal-Tar Shampoos Safe?

Polycyclic aromatic hydrocarbons (PAHs) are one type of hundreds of compounds found in coal tar. Based on the knowledge that exposure to PAHs is associated with an increased cancer risk, these researchers sought to determine whether coal-tar shampoos contribute to the PAH "body burden." Eleven healthy participants washed their hair with a coal-tar shampoo for 30 seconds twice in succession. Urine was collected on the day before the shampooing and on the following two days for measurement of 1-hydroxypyrine (1-OH-P), a PAH metabolite. The mean increases in totally excreted 1-OH-P on the first and second days after shampooing were 10 and 5 times the background values, respectively. The 1-OH-P values on day 1 were similar to those found in cok…