New Indy Odor Investigation

*Updated October 15, 2021


To update and share accurate information with the community, DHEC will continue to add to our New Indy webpages. This week we are providing answers and information about the enforcement process DHEC must follow with regulated facilities. Please send your questions and suggestions for additional updates to

There are two Orders issued to New Indy, one by DHEC under the authority of the South Carolina Pollution Control Act and the other by the US EPA under the authority of the Clean Air Act. The goal of both Orders is for the facility to identify H2S sources onsite that are contributing to the offsite odors and impact to the surrounding communities and to reduce emissions affecting offsite locations. 

DHEC has created a form to gather specific information that will aid in our ongoing odor investigation. Community members and their observations are valuable assets in our investigation. Below is an example map of odor reports that provided complete location and time details. 

Odor Reports Map

Many variables affect the number of odor reports during a time period. The main variable is wind direction and whether or not people are upwind or downwind from New Indy.


New Indy - August Odor Map


We have used citizen reports that include time and place along with local wind speed and direction data to follow air parcels back in time to recreate the path that air has taken. Called back trajectories, and modeled by our meteorologists during a range of conditions, they help identify where parcels of air have been and the potential sources along those paths. Many of the back trajectories that have been modeled indicated that air associated with odor reports previously passed over or near the New Indy plant. 

DHEC's Investigation

As part of DHEC’s investigation, we evaluated permitted facilities in the area, including the New Indy Containerboard facility and nearby wastewater treatment plants, which also have a distinctive odor. The reports that describe the results of these inspections are provided here. 

DHEC worked with state, local, tribal, and federal partners to investigate the odors. North Carolina DEQ indicated to South Carolina DHEC that they investigated their wastewater treatment plants in North Carolina and did not find issues believed to contribute to the odors.

To assist in the investigation and ongoing response, DHEC requested resource assistance from the US EPA:

  1. to bring in pulp and paper mill process experts to assist in joint DHEC and EPA inspections; and
  2. to bring in advanced technology to measure air quality in surrounding communities where odors have been reported

On May 13, 2021, EPA issued an Order to address the endangerment posed by the air emissions of hydrogen sulfide.

Odors from Sulfur Containing Compounds at Regulated Sources

Sulfur odors come largely from decaying organic matter - especially when decaying organic materials are concentrated in one area like a wastewater treatment plant, land application of organic fertilizer and certain industries like pulp and paper mills. The pulp and paper industry is known for its distinctive smell. This smell comes from the decay of wood, which releases naturally occurring sulfur compounds, as well as a sulfur-containing chemicals used in the pulping process.  

Sulfur-containing chemicals are often detected by the human sense of smell in very low concentrations and have an unpleasant odor, sometimes similar to rotten eggs. These chemicals can be smelled at concentrations much lower than those associated with being harmful to health. Odors of any type can trigger symptoms such as headaches and nausea, and  the sense of smell is subjective to each individual. There are no state or federal odor regulations applicable to South Carolina

Weather patterns may also influence the detection of odors. DHEC typically receives odor complaints during changes of seasons, during temperature inversions, and when wind comes from atypical directions. Meteorologists of both South Carolina and North Carolina have confirmed temperature inversions have recently occurred in the area. 

Methyl mercaptan, a sulfur containing compound, is added to natural gas as an odorant so that leaks can be detected. If your home has gas appliances or gas heating or gas fireplaces and you smell gas inside your home that is not also outside of your home, you should leave the home and call the gas company or 9-1-1.

Community Involvement

DHEC takes odor concerns very seriously and remains committed to providing information to those affected by these odors. Community members and their observations are valuable assets in our investigation. Data from citizen odor reports has been and will continue to be used to inform the investigation.  

DHEC provided a form for community members to contribute details of their odor observations to assist in our investigation.   


DHEC and local partners continue to work to resolve this concern. Please check this webpage frequently as it will be updated as additional information about the odor investigation becomes available.  


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