FACT SHEET

Proposed Amendments to Air Toxics Standards for
Cyanide Chemicals Manufacturing

ACTION

•	On January 6, 2021, the U.S. Environmental Protection Agency (EPA) proposed to amend
the 2002 National Emission Standards for Hazardous Air Pollutants (NESHAP) for
Cyanide Chemicals Manufacturing.

•	EPA is proposing minor amendments to enhance the effectiveness of the rule by
improving compliance and implementation.

•	EPA issued the air toxics standards for Cyanide Chemicals Manufacturing on July 12,
2002. The rule established emission limits for process vents, transfer racks, storage
tanks, equipment leaks and some wastewater operations.

•	Following a residual risk and technology review conducted in accordance with the Clean
Air Act (CAA), with this action EPA is proposing to:

o Revise requirements for periods of startup, shutdown and malfunction to be

consistent with recent court decisions;
o Require electronic reporting of performance test results; and
o Add emissions standards for process wastewater emissions that were previously
unregulated.

•	EPA will accept comment on the proposed amendments for 45 days after publication in
the Federal Register.

RESIDUAL RISK ASSESSMENT

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

•	Based on the completed risk assessment, available health information and associated
uncertainties, EPA determined risks from the Cyanide Chemicals Manufacturing source
category are acceptable and provide an ample margin of safety to protect public health.

TECHNOLOGY REVIEW

•	The CAA requires EPA to assess, review and revise air toxics standards, as necessary,
taking into account developments in practices, processes and control technologies. The
technology review of the standards for cyanide chemicals manufacturing facilities did
not identify any developments that would further reduce hazardous air pollutant
emissions beyond the original NESHAP.

BACKGROUND

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

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•	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 the 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 EPA to review
and revise the standards, if necessary, to account for improvements in air pollution
controls and/or prevention.

HOW TO COMMENT

•	EPA will accept comments for 45 days after the proposal is published in the Federal
Register.

•	Comments, identified by Docket ID No. EPA-HQ-OAR-2020-0532 may be submitted by
one of the following methods:

o Go to https://www.regulations.gov/ and follow the on-line instructions for

submitting comments,
o Send comments by email to a-and-r-docket@epa.gov. Attention Docket ID No.
EPA-HQ- OAR-2020-0532.

•	Out of an abundance of caution for members of the public and our staff, the EPA Docket
Center and Reading Room are closed to the public, with limited exceptions, to reduce
the risk of transmitting COVID-19. Our Docket Center staff will continue to provide
remote customer service via email, phone, and webform.

o We encourage the public to submit comments via https://www.regulations.gov/
or email, as there may be a delay in processing mail and faxes. Hand deliveries
and couriers may be received by scheduled appointment only,
o For further information on EPA Docket Center services and the current status,

please visit us online at https://www.epa.gov/dockets.
o For additional information, including the full EPA public comment policy, please
visit https://www.epa.gov/dockets/commenting-epa-dockets.

FOR MORE INFORMATION

•	Interested parties can download a copy of the proposed rule notice from EPA's website
at the following address: https://www.epa.gov/stationary-sources-air-pollution/acetal-
resins-acrylic-modacrylic-fibers-carbon-black-hydrogen.

•	Today's action and other background information are also available electronically at
https://www.regulations.gov/. EPA's electronic public docket and comment system.

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• For further technical information about the proposed rule, contact Nathan Topham,
EPA's Office of Air Quality Planning and Standards, Sector Policies and Programs
Division, at (919) 541-0483 or topham.nathan@epa.gov.

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