Coal Tar or Asphalt Emulsion Sealer: Which Is Right for Livonia?
Coal tar resists salt and fuel better, asphalt emulsion carries about a thousandth of the PAHs, and Michigan has no statewide ban, though one Wayne County township does.
Two sealers, one job
Both products do the same thing: close the top of an oxidized asphalt surface so water, brine and sunlight stop pulling it apart. Coal-tar sealer is made from refined coal tar, a byproduct of coking coal. Asphalt-emulsion sealer is made from asphalt cement, the same binder that holds the pavement together, suspended in water. Both are loaded with sand, applied by squeegee or spray, and need pavement and air at 50 degrees F and rising plus a dry day to cure.
The USGS describes coal tar as the more common product east of the Continental Divide, except in the states, counties and municipalities where its use is prohibited. Coal-tar sealers remain in use in Michigan and are widely sold in the Detroit market, so a Livonia homeowner can be quoted either product and may not be told which one it is.
Where coal tar wins: salt and fuel
The case for coal tar is chemical resistance. The USDA Forest Service guide to asphalt seal coat treatments puts it in one line: unlike asphalt cement, coal tar is resistant to damage from gasoline, diesel, oil, salt and chemicals. On a driveway that takes a winter of brine tracked in from Merriman Road and a summer of drips under the car, that resistance is real.
Asphalt-emulsion sealer is the same material as the pavement, so fuel and oil soften it the way they soften the asphalt underneath. Emulsion products lean on additives to close that gap, and a heavier sand load and a second coat do more for wear than the base chemistry does. The Forest Service guide also notes that coal tar generally costs more, which is one of the drivers on the cost page.
Where asphalt emulsion wins: what wears off the driveway
Sealer does not stay on the driveway. It abrades under tires and feet, and the dust goes into the gutter and the house. The USGS measured coal-tar-based sealcoat at 35,000 to 200,000 milligrams of PAHs per kilogram, about 1,000 times more than asphalt-based sealcoat and roughly 100 times more than used motor oil. In a study of 23 ground-floor apartments, PAH levels in house dust were 25 times higher where the parking lot had been sealed with a coal-tar product.
The EPA classifies seven PAHs as probable human carcinogens, and coal tar and coal-tar pitch are known human carcinogens. Runoff from a sealed lot on Plymouth Road runs toward the Rouge, which is the reason the bans exist. None of that changes how the driveway looks in year two; it changes what gets tracked into the front hall.
Is coal-tar sealer banned in Livonia or Michigan?
There is no statewide ban in Michigan as of this writing. Minnesota and Washington ban coal-tar sealants statewide, and the District of Columbia and Dane County, Wisconsin, ban them locally. In Michigan, the Minnesota Pollution Control Agency's July 2016 inventory of local actions lists bans or ordinances in Ann Arbor, Spring Lake Township and Van Buren Township, plus government-use restrictions in about a dozen other townships and cities. Van Buren Township is in Wayne County, a short drive down I-275. Livonia does not appear on that list.
The legislature has taken it up. Senate Bill 710, introduced November 13, 2025, would prohibit the use and sale of coal-tar and other high-PAH pavement sealants in Michigan; as of its last recorded action it had been referred to the Senate Committee on Energy and Environment. Until something passes, the choice in Livonia is the buyer's, and a property manager with lots in several towns should check each municipality's code before specifying a product.
- Minnesota and Washington: statewide bans.
- District of Columbia and Dane County, Wisconsin: local bans.
- Michigan: no statewide law; Ann Arbor, Spring Lake Township and Van Buren Township have bans or ordinances.
- Livonia: not on the 2016 inventory; confirm with the city before writing a commercial spec.
- Senate Bill 710 of 2025: would ban coal-tar sealants statewide; in committee at its last recorded action.
How to choose for a Livonia driveway or lot
Pick asphalt emulsion when the driveway fronts a house with kids and pets, when the lot drains to a storm inlet, or when the municipality restricts coal tar. Pick coal tar when fuel and salt exposure is the main failure, a fleet yard or a fueling apron, and the code allows it. For driveway sealcoating in Rosedale Gardens or Castle Gardens, the emulsion trade-off is usually a second coat and closer attention to the two-to-four-year resealing interval.
For parking lot sealcoating, name the product in the scope along with the coat count, the sand load and the application temperature floor, so bids compare like to like. A contractor sealcoating across Livonia and the neighboring towns should be able to quote either product and explain the trade-off; if the answer is a brand name and nothing else, ask for the technical data sheet.
What matters more than the product
Prep. Neither sealer bridges a crack or bonds to a wet or dirty surface. Hot rubber crack filling first, oil spots primed, edges trimmed, the surface blown clean, and then two thin coats on a day above 50 degrees F with 24 dry hours behind it. A well-prepped emulsion job outlasts a rushed coal-tar job on the same Blount clay.
The other failure has nothing to do with chemistry. Sealer thinned heavily with water looks identical on the day it goes down and is gone by spring. Ask what the product is, how it is cut, and how much sand is in it, and get the answer in writing before the truck shows up.
Settle the product with the contractor first, then ask for a written scope and quote that names the sealer, the coat count and the sand load before anyone opens a drum.
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Quick Answers
Is coal tar sealer illegal in Michigan?
No. Michigan has no statewide ban as of this writing. Local bans or ordinances exist in Ann Arbor, Spring Lake Township and Van Buren Township, and a statewide bill, Senate Bill 710, was introduced in November 2025 and referred to committee. Livonia is not on the 2016 inventory of local restrictions. Coal-tar sealers remain in use in Michigan and are widely sold in the Detroit market.
Which sealer lasts longer in Livonia winters?
Coal tar resists salt, fuel and oil better, so on a heavily salted, fuel-stained surface it tends to hold up longer per coat. On a typical residential driveway the difference is smaller than the difference made by crack filling, two coats, sand load and a proper cure. Either product needs resealing every two to four years here; a south-facing drive lands near two and a shaded one near four.
Does asphalt emulsion sealer have PAHs too?
Yes, but at a tiny fraction of the level. The USGS puts coal-tar-based sealcoat at 35,000 to 200,000 milligrams of PAHs per kilogram, about 1,000 times more than asphalt-based sealcoat, and found that dust from sealed pavement in eastern cities carried about 1,000 times the PAHs of dust in western cities where asphalt-based products dominate. The pavement itself is asphalt; the emulsion sealer is the same material.
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