There are approximately 500,000 asphalt workers in the United States today who have significantly increased risk of lung, stomach, bladder, and nonmelanoma skin cancer – yet little is known about this particular occupational hazard, and it was rarely studied until the early 1990s. Mike McClean, a researcher at the Harvard School of Public Health, is just one of a handful of scientists who are studying asphalt workers to determine whether this increased risk of disease results from workplace exposure. The Harvard researchers found that DNA damage increased during each day of the work week, suggesting that asphalt exposure resulted in increased cancer risk The biggest finding? That skin absorption of asphalt is higher than that of inhalation, meaning that workers can reduce their risk by covering their skin better, by always wearing gloves and long-sleeved shirts, and washing up more frequently. McClean is currently discussing his results and determining recommendations with the asphalt industry.