Ethylene oxide: Technical Reviews and Outreach to Potentially Affected Communities

Status Report -- Union Carbide, South Charleston, West Virginia

As EPA pursues its mission to protect public health and the environment, addressing ethylene

oxide (EtO) remains a major priority for the Agency. EPA's National Air Toxics

Assessment (NATA), released in August 2018, identified a number of areas (census tracts) with

potentially elevated risk from continuous exposure, over 70 years, to EtO in the

outdoor air. NATA estimated these risks based on EtO emissions from 2014, which were the

most recently available at the time.

NATA is a screening-level analysis that is intended to identify pollutants or areas for closer
examination. Because of this, additional work is needed to better understand emissions in
areas that NATA identified as potentially having elevated risk. EPA has been supporting its state
air agency partners as they conduct that work and identify opportunities for reducing EtO
emissions from individual facilities, while the Agency reviews its national regulations for
industrial facilities that emit EtO. Actual risks today may be higher or lower than NATA
estimated due to several factors, including updated or more refined facility emissions
information, or recent facility changes such as the installation of pollution controls.

The information below describes the technical analyses conducted for Union Carbide in South
Charleston, W. Va., as part of the follow-up work conducted since NATA was issued in August
2018. It also summarizes outreach to nearby communities about the NATA results. EPA is
providing this information, in part, in response to the EPA Office of Inspector General's March
31, 2020, Management Alert which called on EPA to provide information to the 25 communities
that NATA identified as potentially having the highest risk from EtO emissions.

Technical reviews conducted:

The West Virginia Department of Environmental Protection (WVDEP) has requested Region 3
help in air modeling and risk exposure modeling. EPA Region 3 has provided support to WVDEP
with the following:

•	Provided 2014 NATA and EtO findings for the Mid-Atlantic Regional Air Management
Association's (MARAMA) Air Toxics conference in August 2018.

•	Presented 2014 NATA and EtO findings at R3 annual State Air Directors meeting in
September 2018.

•	Shared remodeled risk results using 2017 emissions with WVDEP in July 2019.

•	Coordinated EPA technical call on ambient monitoring of EtO conducted by Office of Air
Quality Planning and Standards (OAQPS) with PA, DE, WV—our states with high risk
facilities, in July 2019.

•	Coordinated EPA webinar on technical methods used for EtO analysis for state and local
agencies and contract laboratories in August 2019.

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Actions to date:

•	An initial modeling effort by R3 in 2019 using meteorological data from the local airport
was considered possibly biased high due to the higher elevation of the location of the
meteorological tower and turbulences at that elevation.

•	WVDEP requested onsite meteorological data from Union Carbide South Charleston, so
that R3 can use that input to the air model in order to get results from localized data.

•	R3 received the raw dataset in September 2020. Initial date files have been processed
and returned to WVDEP in October 2020, the completed files were returned to WVDEP
in early December 2020.

•	WVDEP will then run the air dispersion model, AERMOD, and provide R3 with the
results. R3 will use these results as input to the Human Exposure Model (HEM) to get
new risk exposure results (expected in early 2021)

•	WVDEP has requested R3 take the lead to explain the results to both the facility and the
community once the results have been analyzed.

Outreach conducted:

• R3 has held conference calls with local community advocates in 2019 and plan to update
them after the risk exposure results have been analyzed.

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