Hot mix asphalt

A conveyor belt leads up to three tall grey cylinders at an asphalt mixing plant.Air emissions

A hot mix asphalt plant in Minnesota must get an air emissions permit if:

  • Its potential air emissions are over a certain level, or
  • It's required to follow a federal New Source Performance Standard (NSPS).

Check your emissions

Use this calculator to see if you need an air permit, which air permit to apply for, and whether federal rules affect you: File Hot mix asphalt air emissions calculator (p-sbap5-20)

The calculator covers the following NSPS that affect the need for an air permit:

Compliance tools

See Complying with air permit and rule requirements for more information on hot mix asphalt operating practices, inspections, maintenance, recordkeeping, and air permit due dates.

PDF icon Compliance calendar: Hot Mix Asphalt Plants (p-sbap5-05)

Use the compliance calendar as a free tool to help you stay in compliance with recordkeeping and reporting if your business has a Registration Option D air permit or Nonmetallic Mining and Associated Activities general stormwater and wastewater permit (MNG490000).

Hazardous waste

You need a hazardous waste license if your business produces any amount of hazardous waste. Facilities in Anoka, Carver, Dakota, Hennepin, Ramsey, Scott, or Washington County are licensed and inspected by their county. Facilities in greater Minnesota are licensed and inspected by the MPCA. If you produce only small amounts of hazardous waste, you probably qualify to bring the wastes to PDF icon Very small quantity generators collection programs (w-hw2-51). See the Hazardous waste documents and forms page for information on managing specific types of hazardous waste, such as antifreeze, lead-acid batteries, solvents, waste tires, used oil, and much more.

Annual hazardous waste training is required for businesses that generate 220 pounds or more of hazardous waste a month. Learn more on the General environmental requirements page.

Hazardous waste due dates

Requirement Due date

Hazardous waste generators fee

Mailed to license holders in first quarter, due date on invoice
License application Due August 1 for Greater Minnesota businesses;
Twin Cities metro businesses: contact your county

Stormwater and wastewater

Hot mix asphalt facilities, including portable plants, must have a permit for stormwater and wastewater activities. Any wastewater activities require the Nonmetallic Mining & Associated Activities General Permit (MNG490000) (not to be confused with the air permit for nonmetallic mining that hot mix plants can't use).

The MNG490000 permit allows some wastewater (non-stormwater) activities. However, if wastewater is discharged to surface waters, you must have an individual NPDES/SDS permit. See the PDF icon text of the MNG490000 permit for full requirements and allowances.

Water permit due dates

Requirement Due date
Industrial stormwater quarterly sampling Jan. 21, April 21,
July 21, and Oct. 21
NPDES/SDS general industrial stormwater permit annual reporting March 31
Discharge monitoring reports for MNG49 general permit for non-metallic mining January 22, April 22, July 22, and October 22


PDF icon Asphalt cement aboveground tanks have specific requirements and exemptions due to the high viscosity of asphalt cement. See the storage tanks pages for more information.

Local regulation

Be sure to check with your county, city, and township to see if they have any additional requirements.

Compliance audit checklists

Beyond compliance


Dust pollution is important to control because it can negatively affect product quality, employee health and safety, and impacts on the local community. To minimize dust, consider the following best practices:

  • limit drop heights of materials being transferred to stockpiles, bins, or conveyors
  • cover or water aggregate stockpiles
  • keep stockpiles as compact as possible
  • cover conveyors
  • leave empty space at the top of unenclosed aggregate storage bins
  • routinely inspect and maintain air pollution control equipment such as ducts, connections, housings, pressure gauges, temperature indicators, and flow gauges

Fugitive road dust pollution can be a problem. Minimize dust on haul roads by limiting truck speeds, watering unpaved roadways, and watering or sweeping paved roadways.

General best management practices

  • Noise. Choose hours of operation to minimize noise impact to surrounding properties.
  • Odor. Bad odors can create health and/or compliance problems. Invest in asphalt odor control technologies and products to reduce odors.
  • Tank and chemical storage areas. Routinely inspect for leaks and ensure proper maintenance of fuel tanks and chemical storage areas. Check the containment to ensure it is in good condition.
  • Wetlands. When choosing a site and planning your operations, identify nearby wetlands to minimize impact by not disturbing wetlands and not allowing untreated water and runoff into wetlands.
  • Save energy by feeding your dryer aggregate with less moisture, and insulating tanks, drums, and long runs of pipe. Cover your aggregate pile or, if that is not possible, try to drain it to the north so the sun will dry the south side, and take your aggregate from the south side of the pile. Consider investing in an infrared camera to help you identify heat leaks. Repair heat leaks to save energy and keep energy costs down.
  • Baghouse dust. Dust generated from asphalt plants is commonly added to hot mix asphalt paving mixtures. A factsheet with more information is available from the Federal Highway Administration (FHWA)

PDF icon Case study: Air quality impact study for UMore Park sand and gravel resources, University of Minnesota

This study finds potential air quality impacts such as type of air pollutants in the mining area and identifies options for minimizing those impacts.