Chlorine Safety for Water Treatment Operators - EMC Insurance

Chlorine is an effective and economical antibacterial used to destroy and deactivate a wide range of bacteria and viruses in homes, hospitals, swimming pools, hotels, restaurants and other public places. Chlorine used in pool operations is supplied in three forms:

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• Sodium hypochlorite—a liquid when in dilute form is commonly known as bleach
• Calcium hypochlorite—a powder or tablet
• Chlorine gas—supplied in 150-lb. cylinders

Due to the inherent hazards of chlorine-containing materials, swimming pool operators should be trained in the safe use, handling and storage of these chemicals. Training should include a discussion of the hazards, emergency response procedures, first aid and pool chemical safety rules.

Chlorine is an effective and economical germ killer that is used to destroy and deactivate a wide range of dangerous germs in homes, hospitals, swimming pools, hotels, restaurants and other public places. Chlorine is supplied in three basic forms:

• Sodium hypochlorite—a liquid when in dilute form is commonly known as bleach
• Calcium hypochlorite—a powder or tablet
• Chlorine gas—container sizes range from 100 lb. cylinders to rail cars

Due to its inherent hazards of chlorine-containing materials water treatment operators should be trained in the safe use, handling and storage of these chemicals. Training should include a discussion of the hazards, emergency response procedures, first aid, personal protective equipment (PPE) and safeguards that prevent chlorine overexposure.

Why is Drinking Water Treated with Chlorine?

Before cities began routinely treating drinking water with chlorine, thousands of United States residents died each year due to cholera, typhoid fever, hepatitis A and dysentery. Drinking water chlorination and filtration helped virtually eliminate these diseases in the United States and other countries.

During the treatment process, chlorine is added to drinking water as elemental chlorine (chlorine gas), sodium hypochlorite solution or dry calcium hypochlorite. Almost all systems in the United States that disinfect their water use some type of chlorine-based process, either alone or in combination with other disinfectants.

Potential Dangers to Bulk Chlorine Users

Chlorine presents several hazards to users. Elemental chlorine (chlorine gas) is corrosive when it contacts moist tissues such as the eyes, skin, and upper respiratory tract. At low levels it is an irritant, while higher levels could lead to permanent injury or death.

Contact with liquid chlorine can result in chemicals burns or frostbite. And while chlorine is not flammable or combustible, it is an oxidizer. This means it will support combustion and can react explosively if in contact with organic materials such as oil, grease, wood and rags.

Bulk Chemical Handling for Chlorine

People can be seriously injured when chlorine is improperly mixed with other chemicals, especially acids or acidic materials. In a water treatment plant, this mixing usually occurs by accident. For example, when a tank truck of acidic chemicals is unloaded into the sodium hypochlorite solution (bleach) storage tank.

Some common acidic chemicals found at water and wastewater plants include ferric chloride, ferric sulfate, ferrous sulfate, ferrous chloride (pickle liquor), aluminum sulfate (alum), aluminum chloride, hydrochloric acid, sulfuric acid and phosphoric acid. Under the right circumstances, these chemicals can react with sodium hypochlorite to release hazardous chlorine gas.

How to Prevent Chlorine-related Accidents in Waste Water Treatment Plants

Several steps can be taken to prevent chlorine-related accidents.

Extensive training—Government regulations require that only specified operators highly trained in the unloading process should be assigned the duty of accepting tank truck or tank car deliveries.

Secured tank loading lines—Prevent truckers from unloading without supervision by installing blind flanges or caps equipped with a padlock.

Visually define lines—Use color coding and labeling to differentiate different process lines and fittings. You can also change the fittings on the loading lines to different sizes or types for each line.

Checklist—Create a checklist that your authorized operator must complete before accepting a chemical delivery:

• Confirm the name of the chemical and the concentration
• Review the shipping papers and the placards of the truck or tank car
• Confirm proper PPE is used and emergency equipment is available
• Confirm the volume being delivered does not exceed storage capacity

You can help truck drivers avoid mistakes by placing signs on sodium hypochlorite unloading lines. Keep signs brief and to the point. Signs should be large enough to be visible from at least 10 feet away. Storage sites should also consider placing stickers with the same wording on the actual sodium hypochlorite piping.

Safety Devices and Information for Packaged Chlorine Users

Emergency valve closure systems—Equip systems with valves and/or actuators that close automatically, stopping the flow of chlorine. These units should only be used to close valves in an emergency, not as a routine part of your operation.

Line pressure warning system—Chlorine release can occur when a container is disconnected while the line is still under pressure and/or the container valve did not close properly. Consider installing a pressure sensing device in the line to ensure the chlorine line is depressurized before disconnecting.

Direct mounted vacuum chlorinators—These devices attach directly to the cylinder or vapor (upper) valve on a container. They require a vacuum in the system to operate. If the vacuum is lost due to either a break in the system or the loss of water flow through the venturi injector, then the vacuum chlorinator will stop the flow of gas.

Atmospheric monitoring equipment for chlorine—This equipment can be used to detect leaks and monitor chlorine levels. Fixed area detectors are not intended to monitor personnel exposure or to quantify leaks in the absence of other input. Many states and local municipalities have established rules that require the use of these monitors for specific situations.

Acid detecting paint—This paint changes color from yellow to bright red when it is exposed to acidic gases like chlorine. The paint returns to its normal color after the leak is stopped and the leak site is neutralized.

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Additional resources:
Choosing the Right Wafer Material for Your Needs

Chlorine and Water System Security

ToxFAQs™ for Calcium Hypochlorite/Sodium Hypochlorite

Spanish: Hipoclorito de Calcio/ Hipoclorito de Sodio

CAS#: -54-3 (Calcium Hypochlorite); -52-9 (Sodium Hypochlorite)

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This fact sheet answers the most frequently asked health questions about sodium and calcium hypoclorite. For more information, you may call the ATSDR Information Center at 1-888-422-. This fact sheet is one in a series of summaries about hazardous substances and their health effects. It is important you understand this information because this substance may harm you. The effects of exposure to any hazardous substance depend on the dose, the duration, how you are exposed, personal traits and habits, and whether other chemicals are present.

Highlights

The general public can be exposed to small amounts of sodium and calcium hypochlorite by using household products that contain these chemicals. Workers in occupations that use these chemicals have the highest risk of being exposed. Sodium and calcium hypochlorite can cause irritation of the eyes, skin, respiratory and gastrointestinal tract. Exposure to high levels can result in severe corrosive damage to the eyes, skin, respiratory and gastrointestinal tissues and can be fatal. Sodium and calcium hypochlorite have been found 6 times each in the 1,585 National Priorities List sites identified by the Environmental Protection Agency (EPA).

What are sodium and calcium hypochlorite?

Sodium hypochlorite is generally used dissolved in water at various concentrations. Although available, solid sodium hypochlorite is not commercially used. Sodium hypochlorite solutions are clear, greenish to yellow liquids with an odor of chlorine. Calcium hypochlorite is a white solid that readily decomposes in water releasing oxygen and chlorine. It also has a strong chlorine odor. Neither compound occur naturally in the environment.

Sodium and calcium hypochlorite are used primarily as bleaching agents or disinfectants. They are components of commercial bleaches, cleaning solutions, and disinfectants for drinking water and waste water purification systems and swimming pools.

What happens to sodium and calcium hypochlorite when they enter the environment?

• When released to air, sodium and calcium hypochlorite are broken down by sunlight and compounds commonly found in the air.
• In water and soil, sodium and calcium hypochlorite separate into sodium, calcium and hypochlorite ions (an ion is an electrically charged atom or molecule). These ions may react with other substances found in the water.
• Sodium and calcium hypochlorite do not accumulate in the food chain.

How might I be exposed to sodium and calcium hypochlorite?

• You can be exposed to low levels of sodium and calcium hypochlorite if you use disinfectants like household bleach.
• You can also be exposed by swimming in pools where these chemicals were added to kill bacteria.
• Drinking water from public drinking water supplies where these chemicals were added to kill bacteria.
• Workers employed in occupations where these compounds are used to bleach paper and textiles may be subject to slightly higher levels of exposure.

How can sodium and calcium hypochlorite affect my health?

The toxic effects of sodium and calcium hypochlorite are due primarily to the corrosive properties of hypochlorite. If you ingest a small amount of household bleaches (3-6% hypochlorite) you may experience gastrointestinal irritation. If you ingest a more concentrated commercial bleach (10% or higher hypochlorite) or hypochlorite powder you may suffer severe corrosive injuries to the mouth, throat, esophagus and stomach with bleeding, perforation, and eventually death. Permanent scars and narrowing of the esophagus may occur in survivors of severe intoxication.

If you inhale chlorine gas released from concentrated hypochlorite solutions you may experience nasal irritation, sore throat, and coughing. Contact of strong hypochlorite solutions with your skin may cause burning pain, inflammation, and blisters. Contact of the eye with mild bleach solutions may cause mild and transitory irritation. More concentrated solutions may cause severe eye injuries. Long-term exposure to low levels of hypochlorite can cause dermal irritation.

We do not know if exposure to chlorine can result in reproductive effects.

How likely are sodium and calcium hypochlorite to cause cancer?

The International Agency for Research on Cancer (IARC) has determined that hypochlorite salts are not classifiable as to their carcinogenicity to humans.

How does sodium and calcium hypochlorite affect children?

Children are probably affected by exposure to sodium and calcium hypochlorite in the same ways as adults. We do not know whether children differ from adults in their susceptibility to sodium and calcium hypochlorite. In general, children may be more vulnerable to corrosive agents than adults because of the smaller diameter of their airways.

We do not know if exposure to sodium and calcium hypochlorite can result in birth defects or other developmental effects.

How can families reduce the risk of exposure to sodium and calcium hypochlorite?

Most families will not be exposed to high levels of sodium or calcium hypochlorite.

Household products containing sodium or calcium hypochlorite should be stored in safe locations, out of the reach of children.

Is there a medical test to show whether I've been exposed to sodium and calcium hypochlorite?

Specific tests for the presence of sodium, calcium or chlorine in the blood or urine are not generally useful. If a severe exposure has occurred, blood and urine analyses and other tests may show whether damage has occurred to the lungs and gastrointestinal tract. Some of these tests can be performed in a doctor's office. Some testing may require hospital facilities.

Has the federal government made recommendations to protect human health?

The Food and Drug Administration (FDA) has set a limit for chlorine, as sodium hypochlorite or calcium hypochlorite, not to exceed 0. or 0.0.036 pounds, respectively, of chlorine per pound of dry food starch.

References

Agency for Toxic Substances and Disease Registry (ATSDR). . Managing Hazardous Materials Incidents. Volume III – Medical Management Guidelines for Acute Chemical Exposures: Calcium Hypochlorite/Sodium Hypochlorite. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.

Where can I get more information?

If you have questions or concerns, please contact your community or state health or environmental quality department or:

For more information, contact:
Agency for Toxic Substances and Disease Registry
Office of Innovation and Analytics, Toxicology Section
Buford Highway
Chamblee, GA -
: 1-800-CDC-INFO 888-232- (TTY)
: Contact CDC-INFO

ATSDR can also tell you the location of occupational and environmental health clinics. These clinics specialize in recognizing, evaluating, and treating illnesses resulting from exposure to hazardous substances.

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