FACT SHEET

Final Amendments to Air Toxics Standards for Ethylene Production

ACTION

•	On March 12, 2020, the US. Environmental Protection Agency (EPA) finalized
amendments to the 2002 Ethylene Production National Emission Standards for
Hazardous Air Pollutants (NESHAP).

•	The Ethylene Production NESHAP includes the following emission sources at
ethylene production facilities: storage vessels, ethylene process vents,
transfer racks, equipment leaks, heat exchange systems, waste operations
and ethylene cracking furnaces (and associated decoking operations).

•	Following a residual risk and technology review conducted under the Clean
Air Act (CAA), EPA is finalizing:

o correcting and clarifying regulatory provisions related to emissions during periods of
startup, shutdown and malfunction (SSM), including eliminating exemptions during
periods of SSM, and finalizing alternative work practice standards for certain SSM
events including for PRD releases, visible emissions from flares operating above their
smokeless capacity, decoking of ethylene cracking furnaces, and storage vessel
degassing operations;
o strengthening the heat exchange system requirements;
o adding monitoring and operational requirements for flares; and
o requiring facilities to submit electronic copies of compliance reports and
performance test results and reports.

•	EPA estimates the proposed technology review amendments will achieve
hazardous air pollutant (HAP) emission reductions of 29 tons per year.

•	EPA also estimates that excess emissions of HAP from flares will be
reduced by another 1,430 tons per year.

RESIDUAL RISK ASSESSMENT

•	The CAA requires EPA to assess the risk remaining after application of the final
air toxics standards. This is known as a residual risk assessment.

•	Based on the completed risk assessment, available health information and
associated uncertainties, EPA is finalizing its determination that risks from the
Ethylene Production source category are acceptable and that the standards
provide an ample margin of safety to protect public health.

•	The maximum individual cancer risk for inhalation is estimated to be 100-in-l
million for the Ethylene Production source category.

TECHNOLOGY REVIEW

•	The CAA also requires EPA to assess, review and revise the air toxics standards as

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necessary, taking into account developments in practices, processes and control
technologies since the standards were first issued.

•	The technology review assessment for ethylene production identified cost-
effective developments for heat exchange systems that will reduce emissions of
air toxics.

BACKGROUND

•	The CAA requires EPA to regulate hazardous air pollutants, also known as air toxics,
from categories of industrial facilities in two phases.

•	The first phase is "technology-based," where EPA develops standards for controlling
the emissions of air toxics from sources in an industry group (or "source category").

These maximum achievable control technology (MACT) standards are based on
emissions levels that are already being achieved by the best-controlled and lower-
emitting sources in an industry.

•	Within eight years of setting MACT standards, the CAA directs EPA to assess the
remaining health risks from each source category to determine whether the MACT
standards protect public health with an ample margin of safety and protect against
adverse environmental effects. This second phase is a "risk-based" approach called
residual risk. Here, EPA must determine whether more health-protective standards
are necessary.

•	Also, every eight years after setting MACT standards, the CAA requires that EPA
review and revise the standards, if necessary, to account for improvements in air
pollution controls and/or prevention.

FOR MORE INFORMATION

•	To download a copy of the final rule, go to EPA's website at
https://www.epa.gov/stationarv-sources-air-pollution/acetal-resins-acrylic-
modacrylic-fibers-carbon-black-hydrogen.

•	Today's action notice and other background information are also available ether
electronically at https://www.regulations.gov/. EPA's electronic public docket and
comment system, or in hardcopy at the EPA Docket Center's Public Reading Room.

o The Public Reading Room is located at the EPA Headquarters library, room number
3334 in the WJC West Building, 1301 Constitution Avenue, NW, Washington, DC.
Hours of operation are 8:30 a.m. to 4:30 p.m., eastern standard time, Monday
through Friday, excluding federal holidays,
o Visitors are required to show photographic identification, pass through a metal

detector and sign the EPA visitor log. All visitor materials will be processed through an
X-ray machine as well. Visitors will be provided a badge that must be visible at all
times.

o Materials for this final action can be accessed using Docket ID No. EPA-HQ-OAR-2017-
0357.

•	For further technical information about the rule, contact Andrew Bouchard at EPA's
Office of Air Quality Planning and Standards, at (919) 541-4036 or at
bouchard.andrew@epa.gov.

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