In September, Downtown newsmagazine explored the use and associated health risks of using pavement sealants derived from coal tar, which is a byproduct produced in the distillation of coal into coke. While we found that sealcoat applicators and manufacturers agreed that the coal tar based product was the most durable on the market, the same sources indicated suitable alternatives are available.
Further, existing research on the coal tar-based sealcoat linked it as a significant source of polycyclic aromatic hydrocarbons (PAHs) that are known to be potent carcinogens, and have been linked to cardiovascular disease and poor fetal development. Coal tar pitch, itself, is considered a human carcinogen by the National Toxicology Program.
In its functional state, coal tar sealants provide an added protection and attractive aesthetic to blacktop parking lots. The problem, several studies pointed out, begins when the sealant begins to break down and flake or chip off the pavement. At that point, the substance begins to spread, either by dust that can be tracked into nearby buildings or by stormwater running into drainage and detention systems where it contaminates soils, or runs into local waterways where it impacts aquatic life. As a source of soil contamination in drainage systems, coal tar sealants may pose a substantial financial burden to local governments charged with maintenance of a stormwater management system under federal law. Likewise, property owners near seal-coated parking lots face the cost of mitigating associated contamination.
The time has come for state, county and local lawmakers to take action to prohibit the use and sale of coal tar based sealants as it is too great a source of an environmental pollutant entering our homes and waterways.
Much of the research has been done by the United States Geological Survey and the Minnesota Pollution Control Agency, with support from subsequent academic studies. The information has lead to statewide bans on coal tar sealants in Minnesota and Washington. Several Michigan municipalities have banned the application and sale of coal tar sealants, including Ann Arbor and Van Buren Township.
Those that have already enacted bans on coal tar sealants are aware the products will likely take decades to work their way out of the environment. However, by using existing ordinances as a framework, Oakland County and other communities must start now to reduce the health threat to residents. It becomes especially critical in our county, which sits at the headwaters of key waterways in this part of the state.
Critics of such bans have responded by attacking the researchers motivations and credibility, with the main trade association leading the opposition claiming the entire field of study into emerging pollutants is simply a way to fund new research.
Such ad hominem attacks have little substance to sway us against the type of scientific research that has resulted in previous bans of harmful substances, such as lead and DDT.
So we are calling on elected and appointed officials in local communities, Oakland County and our state lawmakers to show leadership on an issue of utmost importance to residents here and throughout the state and begin working on a ban to the sale and use of coal tar sealants.