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Air: Pulp and Paper Industry Odors

Pulp and paper mills in some areas of Wisconsin are known for their distinctive smell.

One type of odor comes from a special technique, called kraft pulping, that uses heat and chemicals to pulp wood chips for making paper.

Kraft pulping produces gaseous sulfur compounds called “total reduced sulfur,” or TRS, gases. The odors these gases give off are often described as rotten cabbage or rotten eggs.

According to the Environmental Protection Agency, as long as the odors are in line with levels normally found in the environment, they’re considered a nuisance, not a health concern. However, there are times when levels go above normal.

It’s important to note that not all pulp and paper mills produce an odor. Some paper mills use pulp from other mills to make paper. In these cases, the odor is less noticeable. Also, odors can come from places other than kraft pulp mills, including sulfite pulp mills, wastewater treatment plants, and landfills.

Causes of odors

There are three groups of odor-producing compounds created by pulp and paper mills. These include:

  • Ammonia.
  • Reduced sulfides.
  • Other organic compounds.

The odor produced by a mill, plant, or landfill varies based on the source. For instance, sulfite mills give off sulfur dioxide, which has a strong, choking odor. Wastewater treatment plants can smell like rotten garbage, and landfills can smell like decaying organic matter.

Odors also vary depending on:

  • A person’s sensitivity to smell.
  • Changes in wind direction.
  • Mill processing techniques.
  • Temperature.

Health issues associated with odors

Under most weather conditions, even if you can smell odors, they shouldn’t cause health problems because the chemicals are diluted with clean air.

If the chemicals become concentrated by weather conditions, however, they can cause eye and breathing irritation in some people. They also can cause nausea and headaches—and asthma attacks in people with the breathing condition.

High concentrations of these odors can also cause problems for people with emphysema and COPD, or chronic obstructive pulmonary disease. The problems should go away when the odors do.

If you have symptoms you believe are related to air quality, see your doctor. Then contact your local health department or the Division of Public Health at 608-266-1120.

What about cancer?

According to the National Toxicology Program and the International Agency for Research on Cancer, the chemicals that cause odors associated with pulp and paper mills are not suspected to cause cancer.

Also, monitoring data from the Wisconsin Department of Natural Resources (DNR) suggests that the cancer risk in areas with pulp and paper mills is similar to the risk in other urban areas of Wisconsin.

What can I do about odors?

If odors change or get worse near a pulp or paper mill, you can contact the mill and the Wisconsin Department of Natural Resources (DNR).

DNR encourages your comments about air quality. It uses information about past problems when evaluating air permit renewals.

Contact DNR if you want to learn more.

More information

Last revised April 18, 2023