FACT SHEET

Final Amendments to Air Toxics Standards for Hydrochloric Acid Production

ACTION

•	On March 12, 2020, the US. Environmental Protection Agency (EPA) finalized
amendments to the 2003 National Emission Standards for Hazardous Air Pollutants
(NESHAP) for Hydrochloric Acid (HCI) Production located at major sources of air toxics.

•	HCI is used in a variety of industrial processes including: refining ore for the production
of tin and tantalum, pickling and cleaning of metal products, electroplating, cleaning
boilers, neutralizing chemically basic systems, manufacturing fertilizers, dyes, textiles
and rubber, and preparing various food products. HCI is also used as a laboratory
reagent.

•	Following a residual risk and technology review (RTR) conducted under the Clean Air Act
(CAA), EPA determined that risks from the source category are acceptable and that no
new cost-effective controls are available. The agency is not making any changes to the
standards based on the results of the RTR.

•	EPA is, however, finalizing minor amendments to enhance the effectiveness of the
standards by improving compliance and implementation. Specifically, EPA is:

o revising requirements for periods of startup, shutdown and malfunction (SSM) to be
consistent with recent court decisions, including a work practice requirement for
planned periods of vent maintenance; and
o requiring electronic reporting of performance test results and compliance reports.

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 HCI Production source category are acceptable
and that the NESHAP provides an ample margin of safety to protect public health. The HCI
NESHAP applies to specific types of equipment and processes at a facility. Many facilities also
are subject to more than one NESHAP.

Facility-Wide Risks

•	As part of its review, EPA assessed facility-wide risks, which include risks from the HCI
Production source category, as well as other co-located source categories that emit air
toxics, like pesticide or organic chemical manufacturing.

•	EPA estimated that the maximum facility-wide cancer risk is 600-in-l million. This estimated
risk is caused by ethylene oxide emissions from a variety of industrial processes that are not
part of the HCI Production source category. In this assessment, EPA used its 2016 updated
toxicity value for ethylene oxide.

•	EPA is taking a two-pronged approach to address ethylene oxide emissions.


-------
1.	Reviewing CAA regulations for facilities that emit ethylene oxide.

EPA will review and, as appropriate, revise CAA regulations for facilities that emit
ethylene oxide - starting with the NESHAP for Miscellaneous Organic Chemical
Manufacturing facilities and the NESHAP for Commercial Sterilizers. On December 17,
2019, EPA published proposed amendments to the NEHSAP for Miscellaneous Organic
Chemical Manufacturing facilities, some of which emit ethylene oxide (for more
information, see https://www.epa.gov/stationary-sources-air-

pollution/miscellaneous-organic-chemical-manufacturing-national-emission). And on
December 12, 2019, EPA published an advance notice of proposed rulemaking to
solicit information on various strategies for reducing ethylene oxide emissions from
commercial sterilizers (for more information, see https://www.epa.gov/stationary-
sources-air-pollution/ethylene-oxide-emissions-standards-sterilization-facilities).

2.	Working with state air agencies to gather additional information on ethylene oxide
emissions.

EPA is working closely with state and local air agencies to get additional information on
facility emissions to determine whether more immediate emission reduction steps are
necessary or possible in any particular location. This work is ongoing.

TECHNOLOGY REVIEW

•	The CAA also requires EPA to assess, review and revise air toxics standards, as necessary,
considering developments in practices, processes and control technologies.

•	The technology review of the standards for facilities with HCI production did not identify
any developments that would further reduce toxic air pollutant emissions beyond the
original NESHAP.

OTHER AMENDMENTS

•	EPA is removing the exemption from meeting the standards during periods of SSM to be
consistent with a 2008 court decision and clarifying that the standards are applicable at
all times. EPA is adding a work practice requirement for planned periods of vent
maintenance.

•	EPA is requiring electronic submittal of required performance tests and compliance
reports through EPA's Central Data Exchange using the Compliance and Emissions Data
Reporting Interface.

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.

•	The CAA directs EPA to, within eight years of setting the MACT standards, 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 prevention practices and technologies.

FOR MORE INFORMATION

•	Interested parties can download a copy of the final rule notice from EPA's website at the
following address: https://www.epa.gov/stationarv-sources-air-pollution/hydrochloric-
acid-production-national-emission-standards-hazardous.

•	Today's action and other background information are also available either 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, WJC West
Building, Room Number 3334,1301 Constitution Ave., 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 action can be accessed using Docket ID No. EPA-HQ-OAR-2018-
0417.

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


-------