Qualitative Sheen Assessment Results

Sheen Assessment 

Early in the response, under the oversight of EPA and its partners, Norfolk Southern started surface water quality monitoring downstream of the derailment site. Sediment washing and air sparging have been used to restore water quality in Sulphur and Leslie Runs. Air sparging involves spraying water to add air so that oxygen and microbes can break down chemicals. Air sparging is often used in some emergency responses like this derailment to remove chemicals from water.

Stream cleaning has successfully removed chemicals and surface water results have been below levels considered to be hazardous to human health. While surface water is no longer badly impacted, heavily disturbing the creek beds (sediment) can sometimes cause shiny iridescent patches, called sheen, to rise to the water’s surface.

On October 18, 2023, EPA issued an order under the Clean Water Act requiring Norfolk Southern to investigate and cleanup the oily sheens and sediments in Sulphur and Leslie Runs. The qualitative assessment of the stream is complete, and the results are posted below. The first assessment showed that oil-related substances are common in sheens and sheen appears when sediments are disturbed in more than half of the streams.

Crews collected samples of sheens and nearby sediments to check their chemical makeup. Areas with medium and heavy sheens guided planning for exactly how and where additional stream cleanup and monitoring is done.

EPA continues to recommend avoiding Sulphur and Leslie Runs during assessment and cleanup work, and to follow posted warning signage along the creeks. EPA will coordinate with Ohio Department of Health and other partners on reviewing and updating this recommendation.

Observation Data

Crews walked both Leslie and Sulphur Runs and disturbed the creek bed every 25 feet to look for visible sheen. They assessed the creek at approximately 740 locations downstream of the derailment. These locations are highlighted in brown in the dashboard map below.

Crews also assessed the streams at approximately 90 background locations, which are upstream from the derailment site. Background locations are without derailment impacts. By checking these background areas, investigators can compare the streams where oil was and wasn’t released. Background locations are highlighted in green in the dashboard map below.

If crews observed sheen, they assigned a score on a 0-to-3 scale depending on the amount of visible sheen. Zero means there was no sheen and three means there was a lot of sheen. Initially in Leslie Run, 59% of locations had some sheen, compared to 66% of locations in Sulphur Run. In background locations, 92% of areas had no sheen. In the dashboard below, you can select different stream areas to see the breakdown of sheen results. After the fourth reassessment, Leslie Run had 3.5% of locations with some sheen, Sulphur Run had 27%, and background locations had 98.8% of areas with no sheen.

No sheen

Light sheen

Medium sheen

Heavy sheen