Chlorine Supply Chain - Executive Summary

Chlorine

Direct Use Chemical Precursor Chemical

CI2

(liquified gas) 3?6

Inputs to Manufacturing Process:

Sodium Chloride

^ Derivative Water Treatment Chemicals:

*

Hydrochloric Acid Ferric Chloride
Sodium Hypochlorite Ferrous Chloride
Calcium Hypochlorite

,'"v^ % of Total Domestic Consumption
Attributed to Water Sector:

Approximately 5%

Understanding Chemical Supply Chains
Map of Suppliers & Manufacturers

Product Family:

Chior-alkali

CAS No.:

7782-50-5

Shelf Life:

6-12 Months

— RISK OF SUPPLY DISRUPTION (Assessed in 2022)

RISK RATING: Moderate-High

I Aiii

RISK DRIVERS

From 2020 through 2022, a
combination of events resulted
in reduced production capacity,
includ-ing extreme weather
events, equipment failures, and
planned reductions. The loss in
production capacity was
compounded by increased
demand for other uses of
chlorine, such as the production
of high-value chemicals.

RISK PARAMETERS

Criticality: High. Essential for
water disinfection and production
of water treatment chemicals.

Likelihood: High. Previous wide-
spread disruptions in supply that
impacted the water sector.

Vulnerability: Low. Distributed
domestic manufacturing and
supply.

MANUFACTURING PROCESS

Water Treatment Applications

Sodium Chloride

Chlorine

•	Disinfection

•	Algal control

•	Onsite generation of chlorine dioxide

•	Water treatment chemical production

Other Applications

Input

End Use

•	Inorganic and organic chemicals

•	General disinfection

•	Polyvinyl chloride

•	Pulp and paper

DOMESTIC PRODUCTION AND CONSUMPTION, AND INTERNATIONAL TRADE

Domestic Manufacturing Locations (2019):

49, distributed throughout the U.S.

(^) International Trade (2019)

Primary Trading Partner (Imports): Canada
Primary Trading Partner (Exports): Mexico

Domestic Consumption (2019):
10,100 Million kg

¦	Domestic Production (10,000 M kg)

¦	imports for Consumption (211 M kg)

¦	Export of Domestic Production (52 M kg)

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Chlorine Supply Chain - Full Profile

Product Description

Chlorine (Cl2), an inorganic chemical and strong oxidant, is a widely used water disinfectant. It is a foundational
product of the chlor-alkali industry, primarily manufactured through electrolysis of a sodium chloride brine. The
majority of chlorine manufactured in the U.S. is used in organic and inorganic chemical production.

Use in Water Treatment

Chlorine has several uses in water treatment, including primary and residual disinfection, algae control,
oxidation, and on-site generation of chlorine dioxide (AWWA, 2018).

Use as a Precursor to Other Water Treatment Chemicals

Chlorine is used to manufacture hydrochloric acid, sodium hypochlorite, calcium hypochlorite, ferric chloride,
and ferrous chloride (NCBI, 2020).

Other Applications

Chlorine has a wide range of applications. The leading use of chlorine is the production of organic chemicals,
including polyvinyl chloride, for which there is high demand. It is widely used in the production of pulp and
paper, rubber, and solvents. Chlorine is also used as a pesticide and for shrink proofing wool (NCBI, 2020).

Primary Industrial Consumers

In 2021, it is estimated that construction applications such as polyvinyl chlorine and epoxies accounted for the
largest single demand of chlorine. Presently, chlorine is used widely by chlor-alkali manufacturing facilities for
derivative chemical production, a process referred to as captive consumption. A fraction of overall production
(estimated to be 3,600 million (M) kg or 32% in 2022) is destined for sale on the merchant market. Of the
chlorine demand from the merchant market, production of propylene oxide accounts for the largest percentage.
Water treatment (including industrial applications) accounts for the second largest use of merchant market
chlorine. It is estimated that in 2022, water treatment (including industrial applications) will account for 9%
(1.039 M kg of 11.4 B kg) of all domestic production and 27.2% of chlorine available for merchant market
purchase. Municipal wastewater and drinking water applications are anticipated to account for 60% (628 M kg)
of the demand for water treatment, representing approximately 5% of consumption of all domestically
produced chlorine. Of the anticipated 628 M kg of demand for water treatment applications, municipal
wastewater and drinking water are estimated to account for 67% and 33%, respectively (Kreuz et al., 2022).

Manufacturing, Transport, & Storage

Manufacturing Process

Sodium chloride is the raw material most commonly used to produce chlorine. Potassium chloride or
magnesium chloride can also be used but are less common raw materials for domestic production (The Chlorine
Institute, 2014).

Approximately 95% of chlorine is produced using the chlor-alkali process, which involves passing a direct electric
current through a sodium chloride brine (i.e., electrolysis), converting chloride ions to elemental chlorine at the
anode while sodium ions and hydrogen gas collect at the cathode to react and form sodium hydroxide (The
Chlorine Institute, 2014). The general equation for this process is shown in Figure 1. Chlorine is separated from
the solution using one of the following processes: (1) the diaphragm cell; (2) the membrane cell; (3) the mercury
cell; or (4) brine to bleach. The diaphragm method is the most common separation process used in North
America (The Chlorine Institute, 2014). In 2021, membrane cell technology, asbestos diaphragm technology, and
non-asbestos diaphragm cell technology accounted for 46%, 36%, and 1%, respectively, of all domestic chlorine

EPA 817-F-22-020 | December 2022

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Chlorine Supply Chain - Full Profile

production. Potassium chloride membrane cell technology, metal production, and brine to bleach accounted for
the remaining 9% of domestic production (Kreuz et al., 2022).

Sodium Chloride Brine

-» Chlorine Gas +

Hydrogen Gas

+ Sodium Hydroxide

2NaCI + 2H20

-> Cl2

h2

2NaOH











Anode

Cathode

Cathode

Figure 1. Chemical Equation for the Reaction to Manufacture Chlorine
Product Transport

Chlorine is highly corrosive and reacts violently with petroleum products (The Chlorine Institute, 2014; Olin
Corporation, 2020), which dictates how it can be transported. Liquified chlorine gas is sold in bulk quantities and
primarily delivered by specialized railcars to suppliers who repackage and sell the product directly to customers.
Transport of chlorine must adhere to the appropriate methods and regulations related to its status as a toxic
substance, and transit routes designated for chlorine must be go through an approval process. Bulk transport by
rail is very significant. In 2006, it was estimated that rail accounted for 85% of long-distance chlorine movements
nationally (Branscomb et al., 2010). More recently, the Chlorine Institute has noted that rail represents the
largest bulk volume of shipped chlorine (The Chlorine Institute, 2022).

Storage and Shelf Life

Chlorine gas can be pressurized and cooled to a liquified gas and stored in pressure vessels. Small, pressurized
cylinders may be used by smaller water systems, while larger systems may require bulk deliveries of a ton or
more (Hawkins, Inc., 2020; Madison Water Utility, 2020). Pressurized storage vessels should be stored in a cool
place away from direct sunlight. When stored properly, liquified chlorine gas can have a shelf life of 6 to 12
months, depending on purity and size of storage container (Olin Corporation, 2020). Storage durations beyond
recommended shelf life can lead to product degradation and loss of efficacy.

Domestic Production & Consumption
Domestic Production

Production data was collected from the Chlorine Institute, while trade data was collected from the USITC
Dataweb, as shown in Table 1. Both production and trade data are specific to chlorine.

Table 1. Chlorine Production and Trade Data Sources

Production and Trade Data

Category

Data Source

Identifier

Description

Domestic Production

The Chlorine Institute

CAS No.: 7782-50-5

Chlorine

Imports and Exports

U.S. International Trade Commission

HS Code: 2801.10

Chlorine

Total U.S. domestic production of chlorine was approximately 10,000 M kg in 2019 (The Chlorine Institute,
2020). Domestic commercial manufacture of chlorine takes place at chlor-alkali facilities located throughout the
contiguous U.S. The majority of these facilities are owned by a relatively small number of companies including
Olin Corporation, Westlake Corporation, and Oxy Chemical Corporation (The Chlorine Institute, 2020). Westlake
Corporation is a leading global and domestic manufacturer of chlorine, specializing in chlorine derivatives
including polyvinyl chloride (PVC). While Westlake Corporation manufactures and distributes millions of tons of
chlorine each year, a significant percentage of the chlorine manufactured serves as feedstock for the chlorine

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Chlorine Supply Chain - Full Profile

derivative products the company produces (Westlake Corporation, 2016). It is estimated that in 2022, 68% of
domestically produced chlorine will be used in captive consumption such as the applications noted above,
leaving a fraction of domestic production available for merchant market purchase (Kreuz et al., 2022). The
number of domestic manufacturing locations shown in Figure 2 represents operating facilities as of 2019. Supply
of NSF/ANSI Standard 60 certified chlorine for use in drinking water treatment is also widely distributed
throughout the U.S. (NSF International, 2021). For a more current listing of manufacturing locations and supplier
locations, visit the U.S. Environmental Protection Agency's (EPA's) Chemical Locator Tool (EPA, 2022).

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^ 49 Domestic Manufacturing Locations (The Chlorine Institute, 2019)



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Figure 2. Domestic Supply and Manufacturing of Chlorine
Domestic Consumption

U.S. consumption of chlorine in 2019 is estimated at 10,100 M kg. This estimate includes production of 10,000 M
kg, import of 211 M kg, minus export of 52 M kg (The Chlorine Institute, 2020; USITC, 2020), as shown in Figure
3. Imports and exports represent small quantities when compared to domestic production. In the case of
chlorine, there is limited spare capacity in primary sources of chlorine imports (Canada and Mexico).

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Chlorine Supply Chain - Full Profile

Domestic Consumption (2019):
10,100 Million kg

I Domestic Production (10, 000 M kg)
¦ Imports for Consumption (211 M kg)
I Export of Domestic Production (52 M kg)

Figure 3. Domestic Production and Consumption of Chlorine in 2019

Trade & Tariffs

Worldwide Trade

Worldwide import and export data for chlorine are reported through the World Bank's World Integrated
Trade Solutions (WITS) software, as a category specific to chlorine. In 2021, the U.S. ranked third worldwide
in total exports and first in total imports of chlorine. In 2021, Canada ranked first worldwide in total exports
(WITS, 2022), as shown in Table 2.

Table 2. WITS Worldwide Export and Import of Chlorine in 2021

2021 Worldwide Trade
Chlorine (HS Code 2801.10)

Top 5 Worldwide Exporters

Top 5 Worldwide Importers

Canada

275 M kg

United States

305 M kg

France

55 M kg

Hungary

27 M kg

United States

44 M kg

Belgium

23 M kg

Thailand

19 M kg

Malaysia

18 M kg

Belgium

18 M kg

Switzerland

17 M kg

Domestic Imports and Exports

Domestic imports and export data are reported by USITC in categories specific to chlorine. Figure 4 summarizes
imports for consumption1 and domestic exports2 of chlorine between 2015 and 2020. During this period, the
overall quantity of exports and imports remained relatively steady, with imports for consumption exceeding
domestic exports. Over this five-year period, Mexico was the primary recipient of domestic exports while
Canada was the primary source of imports (USITC, 2020). There is limited spare capacity for additional imports
to the U.S. from Canada due to the level of demand in Canada and limited transportation (rail) logistics from
Mexico.

1	Imports for consumption are a subset of general imports, representing the total amount cleared through customs and entering
consumption channels, not anticipated to be reshipped to foreign points, but may include some reexports.

2	Domestic exports are a subset of total exports, representing export of domestic merchandise which are produced or manufactured in
the U.S. and commodities of foreign origin which have been changed in the U.S.

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Chlorine Supply Chain - Full Profile

Domestic Trade of Chlorine
250	HS Code 2801.10

200

150

100

50

2015 2016 2017	2018 2019	2020

¦	Imports from Canada	¦ Exports to Mexico

¦	Imports from Mexico	¦ Exports to Canada

¦	Imports from Other Countries	Exports to Other Countries

Figure 4. USITC Domestic Import and Export of Chlorine between 2015 and 2020

Tariffs

Imports of chlorine are almost exclusively supplied from Canada and Mexico. There is no general duty for import
of chlorine (USITC, 2022), as summarized in Table 3. Imports from China are subject to an additional duty of 25%,
though this has not had an impact on domestic trade dynamics for elemental chlorine. China, one of the largest
chlor-alkali producing nations, is expected to drive future growth in chlor-alkali production (Kreuz et al., 2022).

Table 3. 2020 Domestic Tariff Schedule for Chlorine

HS Code

General Duty

Additional Duty - China
(Section 301 Tariff List)

Special Duty

2801.10

None

25%

None

Market History & Risk Assessment

History of Shortages

During the COVID-19 pandemic there was a significant increase in the demand for many chlorine derivative
products due to increased disinfection of buildings, equipment, surfaces, etc. in an effort to reduce the spread
of COVID-19. Concurrent with this increased demand, there was a temporary loss of approximately 28% of
domestic chlor-alkali production capacity when Winter Storm Uri directly hit the Gulf Coast region in February
2021 (The Chlorine Institute, 2021). Furthermore, in spring and summer of 2021, a number of chlor-alkali
production facilities experienced significant equipment failures resulting in additional, temporary losses in
production capacity. While some of these impacted facilities were located in the Gulf Coast region, others were
located in West Virginia, Utah, and Washington. Later in the summer of 2021, there was a permanent reduction
in chlor-alkali production capacity at facilities located in New York, Alabama, Louisiana, and Texas. The
reductions in chlor-alkali production capacity that occurred in 2021 were compounded by the impacts of
COVID-19 (Powder and Bulk Solids, 2021; Prohaska, 2021). Changes to domestic chlorine production are known
to have a direct impact on the availability of chlorine for domestic consumption, since imports represent a small
fraction of overall consumption (Kreuz et al., 2022). This was exemplified by decreased allocations of chlorine

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Chlorine Supply Chain - Full Profile

and sodium hypochlorite for drinking water and wastewater systems in California, Oregon, Washington, Alaska,
Utah, Missouri, Ohio, Pennsylvania, New York, Massachusetts, Louisiana, and Florida, as reported directly to EPA.

A threatened rail carrier work stoppage in September 2022 highlighted the dependence of the domestic chlorine
supply chain on a complex national rail network for producers, suppliers, and end-users. Due to the
concentration of chlor-alkali facilities along the Gulf Coast combined with widespread need for chlorine, long-
distance transport of chlorine is often required. Additionally, a significant number of domestic manufacturers of
derivative water treatment chemicals are almost exclusively reliant on rail delivery of chlorine for production
needs (Branscomb et al., 2010).

Risk Evaluation

The complete risk evaluation methodology is described in Understanding Water Treatment Chemical Supply
Chains and the Risk of Disruptions (EPA, 2022b). The risk rating is calculated as the product of the following
three risk parameters:

Risk = Criticality x Likelihood x Vulnerability
Criticality	Measure of the importance of a chemical to the water sector

Likelihood Measure of the probability that the chemical will experience a supply disruption in the
future, which is estimated based on past occurrence of supply disruptions

Vulnerability Measure of the market dynamics that make a chemical market more or less resilient to
supply disruptions

The individual parameter rating is based on evaluation of one or more attributes of the chemical or its supply
chain. The ratings and drivers for these three risk parameters are shown below in Table 4.

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Chlorine Supply Chain - Full Profile

Table 4. Supply Chain Risk Evaluation for Chlorine

Risk Parameter Ratings and Drivers

Criticality	High

Chlorine is essential and has
widespread application as a
disinfectant and strong oxidant in
both drinking water and wastewater
treatment. It is a precursor in the
production of several other critical
water treatment chemicals, and
changes in availability or price may
impact availability of derivative water
treatment chemicals.

Likelihood	High

The water sector has experienced
widespread chlorine supply
disruptions in the past. From 2020
through 2022 disruptions in the
supply of chlorine occurred due to an
increase in demand due to the COVID-
19 pandemic and a decrease in supply
as a result of both temporary losses in
production capacity due to equipment
failures and extreme weather events
and permanent, planned reductions in
production capacity.

Vulnerability	Low

Strong domestic manufacturing
capabilities and a distributed
manufacturing base provide some
resilience to supply disruptions.
However, facility closures in 2021 and
the potential for future losses in
production capacity could increase
vulnerability.

Risk Rating: Moderate-High

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References

American Water Works Association (AWWA), 2018. B301 Liquid Chlorine. Denver, CO: American Water
Works Association.

Branscomb, L., Fagan, M., Auerswald, P.E., Ellis, R. and Barcham, R., 2010. Rail Transportation of Toxic
Inhalation Hazards: Policy Responses to the Safety and Security Externality. Harvard Kennedy School of
Government. Retrieved from

https://www.hks.harvard.edu/sites/default/files/centers/taubman/files/Fagan UTC20 working paper
2010.pdf

EPA, 2022a. Chemical Suppliers and Manufacturers Locator Tool, retrieved from

https://www.epa.gov/waterutilityresponse/chemical-suppliers-and-manufacturers-locator-tool

EPA, 2022b. Understanding Water Treatment Chemical Supply Chains and the Risk of Disruptions, retrieved
from https://www.epa.gov/waterutilityresponse/water-sector-supplv-chain-resilience

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Chlorine Supply Chain - Full Profile

Hawkins, Inc., 2020 Conversation with Hawkins Water Treatment Chemical Sales and Technical Services

Kreuz, H., Kovics, N., Suarez, L., Lopez, A., and Herzog, N., 2022. Impact of EPA's Proposed Asbestos-
Diaphragm Chlor-Alkali Rulemaking. Chemical Market Analytics. Retrieved from
https://www.americanchemistrv.com/content/download/11507/file/lmpact-of-EPAs-Proposed-
Asbestos-Diaphragm-Chlor-Alkali-Rulemaking.pdf

Madison Water Utility, 2020. Email exchange with Madison Water Utility Supply Managers Jennifer Allan
and Joe Demorett.

National Center for Biotechnology Information (NCBI), 2020. PubChem Compound Summary for CID 24526,
Chlorine. Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/24526

NSF International, 2021. Search for NSF Certified Drinking Water Treatment Chemicals, retrieved from
https://info.nsf.org/Certified/PwsChemicals/

Olin Corporation, 2020. Conversation with Olin Corporation Technical Services.

Powder & Bulk Solids, 'Olin to Cut Chlor Alkali Capacity at Alabama Plant,' Powder & Bulk Solids, March 16,
2021, retrieved from https://www.powderbulksolids.com/chemical/olin-cut-chlor-alkali-capacity-
alabama-plant

Prohaska, T., 'Occidental Chemical to close Niagara Falls plant; 130 jobs lost.' The Buffalo News, August 19,
2021, retrieved from https://buffalonews.com/business/local/occidental-chemical-to-close-niagara-
falls-plant-130-iobs-lost/article ddb5463c-010a-llec-a536-9b2a8e99ba71.html

The Chlorine Institute, 2014. Pamphlet 1: Chlorine Basics. The Chlorine Institute. Retrieved from
https://www.chlorineinstitute.org/stewardship/chlorine/chlorine-manufacture/

The Chlorine Institute, 2020. Pamphlet 10: North American Chlor-Alkali Industry Plants and Production Data
Report, Edition 2019.

The Chlorine Institute, 2021. U.S. Chlorine/Sodium Hydroxide Production and Shipment Report, September
2021.

U.S. International Trade Commission (USITC), 2020. USITC DataWeb, retrieved from
https://dataweb.usitc.gov/

U.S. International Trade Commission (USITC), 2022. Harmonized Tariff Schedule (HTS) Search, retrieved from
https://hts.usitc.gov/

Westlake Corporation, 2016. Product Stewardship Summary: Chlorine. Westlake Corporation. Retrieved from
https://www.westlake.com/

World Integrated Trade Solutions (WITS), 2022. Trade Statistics by Product (HS 6-digit), retrieved from
https://wits.worldbank.org/trade/countrv-bvhs6product.aspx?lang=en#void

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