United States <
                     : Environmental Protection
                     Agency	
                       Prevention/Pesticides
                       And Toxic Substances
                       (75Q8W)
ERA-738-F-99-001
February 1999
SERA   R.E.D.   FACTS
          Pesticide
     Reregistcation
        Use Profile
                     Chlorine  gas
     All pesticides sold or distributed in the United States must be registered
 by EPA, based on 'scientific studies showing that they can be used without
 posing unreasonable risks to people or the environment. Because of advances
 in scientific knowledge/the law requires that pesticides which were first
 registered years ago be reregistered to ensure that they meet today's more
 stringent standards.                          ,
     In evaluating pesticides for reregistration, EPA obtains and reviews a-
 complete set of studies from pesticide producers, describing the human health
 and environmental effects of each pesticide. The Agency imposes any
 regulatory controls that are needed to effectively manage each pesticide's risks.
, EPA then reregisters pesticides that can be used without posing unreasonable
 risks to human health or the environment.
     When a pesticide is eligible for reregistration, EPA announces this and
 explains why in a Reregistration Eligibility Decision (RED) document. This
 fact sheet summarizes the information in the RED document, for reregistration
 Case 4022, chlorine gas.

     Chlorine gas is used in water treatment to disinfect drinking water,
 swimming pools, ornamental ponds and aquaria, sewage and wastewater, and
 other types of water reservoirs. Chlorine gas also is used as a disinfectant,
 microbistat/microbicide and algicide in food processing systems, pulp and
 paper mill systems, and commercial and industrial water cooling systems.' It is
 used in washing meat, fresh produce  and seeds to control decay-causing
 microorganisms.                    -       ,
     Chlorine is formulated as a pressurized gas and distributed in large
 stationary containers such as tank cars or trucks and 150-pound to 1-foB
 cylinders. It is intended for use only  by trained, experienced persosanel, under
 the supervision of the registrant and in accordance with state and municipal
 regulatory requirements.                 •     ,'...'-	

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   Regulatory
        History
Human Health
  Assessment
      Chlorine gas was first registered in the U.S. in 1948, as a disinfectant for
 use i*1 swimming pools, drinking water, cooling towers arid sewage systems.
 In 1976, chlorine gas was classified for general use based on the premise that
 industrial users already were adequately  trained in its use.  Chlorine gas was
 declared exempt from the requirement of a tolerance when used in solution on
 raw agricultural commodities in 1991 because measurable residues are not
 expected. EPA required additional generic data in a Data Call-In notice issued
 in November 1.993.  Currently, 97 pesticide products containing the active
 ingredient chlorine gas are registered.                    .
      The Food and Drug Administration (FDA) regulates the use of chlorine
 gas hi solution as a food contact surface  sanitizer.  EPA's Qffice of Water
 regulates its use in potable water systems.
                                                   i          •
 Toxicity
      In human poisoning incidents involving accidental ingestion of household
 bleach, chlorine has caused a burning sensation hi the mouth and throat,
 irritation to the digestive tract and stomach, and vomiting. Exposure to
 chlorine gas causes effects ranging from  bronchitis, asthma and swelling of the
 lungs, to headaches,  heart disease and meningitis.  Acute exposure causes more
 severe respiratory and lung effects, and can result in fatalities. More often,
 however, the effects  are not permanent; complete and rapid recovery generally
 occurs with treatment.
      Chlorine disinfectants have been shown to cause occupational dermatitis
 or irritation of the skin. People who are  asthmatic  or allergic to chlorine may
 be at high risk for adverse reactions after inhaling or ingesting chlorine, for
 example, after drinking treated water.
      Technical grade chlorine (gas and  liquid) and its byproducts,
 hypochlorous acid and hypochlorite ions, are highly toxic and corrosive, and
 have been placed hi Toxicity Category I  (indicating the highest degree of acute
 toxicity) for oral, dermal, eye and inhalation effects.  EPA waived several acute
 toxicity studie^ •• ,;  .;  ijbchronic toxicity studies for chlorine due to its known
 acute toxic;*     , „ .  rrc(?;veness.
      Pr ,    j 4 2 ••;•; tar chronic inhalation study  showed effects consistent
                  igs. Even the lowest  exposures resulted in measurable cell
              ;  ~rily as pulmonary lesions. Additional long-term testing is not
 asce:  ;;     ;i   uie likelihood of additional effects being identified for chlorine
per  I; Demote.
      Diverse results have been reported for chronic, exposure to chlorine in
 drinking water.  EPA has classified chlorine as a Group D carcinogen (not
 classifiable as to human carcinogenicity), based on a 1990 National Toxicology
 Program (NTP) study.  That study showed equivocal evidence of cancer in
 female rats (increased leukemia) and no evidence hi male rats or hi male and
                   witl ^it*
                   de in?

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 female mice. The International Agency for Research on Cancer (I ARC) also
 determined in 1991 that chlorinated drinking water is not classifiable as to
 human carcinogenicity. Chlorine has not been shown to cause reproductive,
 developmental or mutagenic effects.

 Dietary Exposure
       Pursuant to 40 CFR 180.1095, Chlorine gas is exempt from the
 requirement of a tolerance when used pre- or postharvest on all raw
 agricultural commodities. Use of chlorine in food processing water systems to
 prevent decay of raw agricultural commodities may result in residues on treated
 produce; however, finite residues or residues abbve naturally occurring
 background levels are not expected.  Similarly, if livestock ingest chlorine-
 treated water, finite residues or residues above background levels are not
 expected to occur in meat, milk or eggs.         ~
       Chlorine gas used as a food contact surface sanitizer on food, meat or
 poultry processing premises and equipment is under FDA's regulatory purview.
 EPA regulates contaminants hi drinking water under the Safe Drinking Water
 Act (SDWA).  The Office of Drinking Water .has recently established a
 Maximum Residual Disinfectant Level (MRDL) of 4 mg/L for chlorine. An
 MRDL is an enforceable Federal Standard.

 Occupational and Residential  Exposure
       Chlorine gas is metered into water through closed systeriis hi
 manufacturing processes or from large stationary containers such as tank cars,
 tank trucks and cylinders. Given current use patterns of chlorine gas, there is
 potential for dermal and inhalation exposure to applicators and other people
 exposed to chlorinated water including swimmers, bystanders and workers in
 food processing plants and water/sewage treatment plants.
       Occupational exposure guidelines have been established by OSHA and
 other domestic and foreign sources. Post-application exposure to chlorine
 while swimming in treated pools is not believed to be significant, if label
 requirements are followed.                                .-•:.-
     - A significant number of accidents and injuries resulting from the use of
 chlorine gas  as a pesticide have been reported by the American Association of
 Poison Control Centers, .the Chlorine Institute, the California Pesticide Illness
 Surveillance Program and others. In California, most accidents involved
, maintenance or equipment failure of chlorinator systems. The most common
 FIFRA use-related exposures occurred at food processing plants. A significant
 number of the incidents reported were attributed to application error.  While
 there were some residential pool incidents, most occurred in connection with
 public/commercial pool chlorinator  systems. In Florida, four applicators have
 died as a result of incorrectly apply ing chlorine gas,                    <

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               Human Risk Assessment
                     Risk to the public is not anticipated from consuming food or water
               treated with chlorine. Although residues may remain on fruits and vegetables
               as a result of their treatment with chlorine solution, these residues are exempt
               from tolerance requirements and are not believed to pose risks. Residues
               above background levels are not expected in meat, milk or eggs as a result of
               chlorine use in drinking water. Use of chlorine to sanitize food contact
               .surfaces and food .processing equipment presumably does not result in residues
               of concern in foods (this use is under FDA's jurisdiction). EPA's Office of
               Drinking Water regulates chlorine hi drinking water supplies under the SDWA.
                     The Agency has concluded that there is a need to better characterize the
               reproductive a developmental risks associated with drinking water in order to
               assure that children, infants and  fetuses not face unreasonable risk from chronic
               exposure to drinking water byproducts.  Because of the high levels of
               exposure, both in terms of population (greater than 200,000,000) and
               individual consumption of chlorinated drinking  water, it is necessary to assess
               the associated risks with greater certainty.       ,           .    .
                     Three water treatment byproducts hi particular have been identified for
               which the health effects need to  be better characterized.
               Bromodichloromethane, dichloroacetic acid, and dibromoacetic acid have been
               identified as having health  effects in laboratory  studies. Because these
               compounds are the most common toxicologically significant halogenated
               hydrocarbons that have not been completely characterized, additional testing
               on these compounds will improve the Agency's ability to assess chronic risks
               from drinking water exposure.
                    EPA has significant concerns about applicator and post-application
               exposure to chlorine gas because it is highly toxic for all routes of exposure.
               The greatest risk of poisoning accidents from chlorine is to applicators and
               bystanders from accidental exposures resulting from use of chlorine  gas hi
               public/commercial swimming  pools, and  to applicators and workers  hi
               industrial food settings. Two other uses,  pulp/paper mills and cooling towers,
               also pose a significant risk because of chlorinator system failure and
               maintenance operations. The reported poisoning incidents strongly  suggest
               that the use of chlorine gas hi these situations presents a significant risk of
               acut   >xicity to applicators, other workers and bystanders.  To mitigate this
.               r'  ,/: PA is requiring Restricted Use Pesticide classification for the  use of
               i  i  i ifte gas in food processing plants, public/commercial swimming pools,
               "," Jp,"paper mills and cooling towers so that in the future these uses will be
                mite ! to trained, certified  applicators. In addition, EPA is requiring
                igiiificant revisions to product labeling through the RED, so labels will contain
               sufficient specific use information. The labeling improvements are expected to

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                     adequately address the risks: associated with water/sewage treatment and
                     residential pool use, which will, still be classified as general use.

Environmental   EnvironmentalFate
   Assessment        Chlorine hydrolyses in water to form hypochlorite and hypochlorous
       ,              acid. Hypochlorous acid is an oxidizing agent—it has a sanitizing effect on
                     organic and inorganic contaminants. Disinfection by chlorination is achieved
             1        by maintaining a "free residual chlorine" concentration in solution.    -'
                          When treated effluent is released into receiving waters, free residual
                     chlorine dissipates rapidly (it has a half-life of 1.3 to 5 hours). The ultimate
                     'fate of chlorine-containing effluent is site specific, and depends on factorsi such
        s             as the chemical constituents of the receiving waters, their -temperature, the
                   '  dilution ratio and the intensity of sunlight.

                     Ecological Effects
                 ,         Studies on lithium hypochlorite were used to satisfy the data       '•••,.
                     requirements for chlorine used as an industrial biocide, since both form
                     hypochlorous acid when dissolved in water.
                          Lithium hypochlorite is practically non-toxic to birds on a subacute
                     dietary basis.  However, chlorine is very highly toxic to fish and freshwater
          '.  '  ,      invertebrates.

     '          ' '"                       "'-.     .''!''
                     Ecological Effects Risk Assessment
           .   (           In receiving waters from facilities using chlorine, if acute, levels of
                     concern are exceeded, a significant risk to aquatic organisms and endangered
                     aquatic organisms can be expected. Levels of concern (equaling one-half of
                     the EC50) are 0.009 ppm for aquatic invertebrates, 0.023  ppm for freshwater
                     fish, and 0;013 ppm for esloiarine organisms. Levels of concern for endangered
                     species (equaling one twentieth of the EC50) are 0.85 ppb for aquatic
                     invertebrates, 2-3 ppb for freshwater fish, and 1.3 ppb for estuarine
                     invertebrates.                                                  .
                          Uses of chlorine that are not regulated under the NPDES permit
                     program, including swimming pool, aquaria and indoor use patterns (fruit arid
 '.."••••    •           vegetable rinsing and food processing), should produce only intermittent
                     discharges of minimal concentration into lakes  or streams, resultingin minimal
                     .environmental exposure.                                          .
                          Other chlorine uses, including water cooling tower, sewage treatment  •
                     plant, and pulp and paper mill uses, are mcluded in the NPDES permit
                     programs administered by EPA's Office of Water. Effluent discharges
                   .  containing chlorine are  regulated under NPDES permits to reduce the impact

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                          on water bodies. The maximum concentration of chlorine allowed in each
                          effluent stream is set on a site-specific and use-specific basis, to achieve the
                          lowest possible concentrations of chlorine in each receiving stream. No '
                          significant adverse effects to aquatic organisms are anticipated from discharges
                          of chlorine under the NPDES permitting system.
    Additional Data
            Required
  Product Labeling
Changes Required
Endangered Species
      If acute levels of concern are exceeded in receiving waters from facilities
using chlorine, a significant risk to endangered aquatic organisms can be
expected. EPA is working with the U.S.- Fish and Wildlife Service to develop a
program to avoid jeopardizing the continued existence of identified species by
the use of pesticides. When this program goes into effect, endangered species
labeling may be required.

      The generic data base for chlorine is substantially complete to
characterize acute risks. For the majority of exposure scenarios, enough data
exists to adequately characterize chronic risks, also. Regarding the drinking"
water treatment use, although the quality of data is sufficient to reregister this
public health use, there is some uncertainty regarding the health effects of
halogenated byproducts that may be present. The Agency will be requiring the
submission of reproductive and developmental studies on
bromidichloromethane, dichloroacetic acid, and dibromoacetic acid.  The
Agency also is requiring product-specific data, including product chemistry, as
well as revised Confidential Statements of Formula (CSF) and revised labeling
for reregistration.                  ,

      All end-use products containing chlorine must comply with EPA's
current regulations and labeling requirements. The table containing the specific
labelling requirements is included in the RED document and as a supplement to
this Fact Sheet.  It specifies detailed labeling requirements and guidance,
covering the following areas:
                               Use Directions - The end use label must indicate specific intended uses,
                               and must provide specific directions for each use. Products must be
                               labeled for restricted use sites or general use sites, not both. The
                               standard Precautionary Statements and Statement of Practical Treatment
                               have been reworded (please see the RED).
                               Standard Labeling for Chlorine Products - Please see the RED for
                               exact label language pertaining to:
                               • The Restricted Use Pesticide legend and usage paragraphs;
                               • Statement of Practical Treatment/First Aid;

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                        •  Precautionary Statements/Hazards to Humans and Domestic Animals
.-•.'•                    (includes Personal Protective Equipment requirements);
                        •  Environmental Hazards;                                   ...  .  .
                        •  Chemical and Physical Hazards;
                        •  Directions for Use;
                         N    "      '                 ,       v              t
                        •  Spill and Leak Procedures;
                        •  Storage and Disposal;
                        •  Disposal of Container.
                  •     Guidance for Specific Directions for Use - See the RED for guidance
                        and sample directions, including:                 -  '   '
                        •  What specific directions for use should include;
                        •  Use directions for swirnrning pool water treatment products;
                        •  Directions for treating sewage and waste water;
                        •  Directions for control of microbiological slimes in cooling towers or
                        pulp and paper mill process water systems;
                        •  Directions for treatment of municipal water supplies;
         .•-•''-..-•    *  Directions for treating raw fruits and vegetables;
                        •  Directions for various methods used for sanitization of hard,
                        nonporous food contact surfaces;
                        •  Directions for treatment of other hard surfaces.
                  •     Effluent Discharge Statement - All end-use (or manufacturing use)
                  products that may be contained in ah effluent discharged to the waters of the
                  U.S. or municipal sewer systems must bear the following statement:

                        "Do not use in facilities discharging directly or indirectly to the
            ,            estuarine or marine environment."

                        To reduce environmental rjsk from chlorinated water discharge and
                  disposal, product labels must include the statements pertaining to effluent
                  discharge under the NPDES permitting system (refer to PR Notice 93 -10) and
     ,             disposal under any applicable federal laws after the above statement.

 Regulatory         AlLCurrently registered pesticide products containing chlorine can be
 Conclusion   usec^ without causing unreasonable adverse effects to humans or the
                  environment, in accordance with the revised labeling specified in this RED.
                  Therefore, all chlorine products and uses are eligible for reregistration.
          .  •'.            Chlorine products registered for use hi non-residential swimming pools,
                  pulp and paper mill processes, and industrial food processing plants and
   ,.               cooling towers are being reclassified as Restricted Use Pesticides due to

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                 chlorine's extreme acute toxicity plus many associated human poisoning
                 incidents.  These products must bear Restricted Use Pesticide labeling no
                 sooner than October 1, 2000, and no later than April 1, 2001.
                      Chlorine products registered for drinking water, sewage and wastewater
                 treatment uses and residential pool use will be considered unclassified. The
                 Agency does not support classifying commercial applications of residential
                 pools as a Restricted Use because few related accidents or incidents have been
                 reported.  Additionally for water treatment, applicators already are trained and
                 certified by the states to perform these uses.
                      Products containing chlorine as  the sole active ingredient will be
                 reregistered once the required product-specific data, CSF and revised labeling
                 are received and accepted by EPA. Products containing other active
                 ingredients will be reregistered only after the other active ingredients  also are
                 determined to be eligible for reregistration.

   For MorG        EPA is requesting public comments on the Reregistration Eligibility
Information   Decision (RED) document for Chlorine Gas, during a 60-day time period, as
                 announced in a Notice of Availability  published in the Federal Register. To
                 obtain a copy of the RED document or to submit written comments, please
                 contact the Pesticide Docket, Information and Record Integrity Branch,
                 Information Resources Services Division (7502C), Office of Pesticide
                 Programs (OPP), US EPA, Washington, DC 20460, telephone 703-305-5805.
                   ,  Electronic copies of the RED and this fact sheet are available on the ,
                 internet. See http://www.epa.gov/REDs.
                      Printed copies of the RED and fact sheet can be obtained from EPA's
                 National Center for Environmental Publications and Information
                 (EPA/NCEPI), PO Box 42419, Cincinnati, OH  45242-0419, telephone 513-
                 489-8190, fax 513.-489-8695.
               -       Following the comment period, the Chlorine Gas RED document also
                 will be available from the National Technical Information Service (NTIS),
                 5285 Port Royal Road, Springfield, VA 22161, telephone 703-605-6000 or
                 800-553-6847.
                      For more information about EPA's pesticide reregistration program, the
                 Chlorine Gas RED, or reregistration of individual products containing chlorine
                 gas, please contact the Special Review and Reregistration Division (7508W),
                 OPP, US EPA, Washington, DC 20460, telephone 703-308-8000.
                      For information about the health effects of pesticides, or for assistance in
                 recognizing and managing pesticide poisoning symptomsj please contact the
                 National Pesticides Telecommunications Network (NPTN).  Call
                 toll-free 1 -800-858-7378, between 9:30 am and 7:30 pm Eastern Standard
                 Time, Monday through Friday.

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