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Significant New Alternatives Policy Program

Fire Extinguishing and Explosion Prevention Sector

Risk Screen on Substitutes for Halon 1301

Total Flooding Systems in Normally Unoccupied Spaces

Substitute: KSA

This risk screen does not contain Clean Air Act (CAA) Confidential Business 

Information (CBI) and, therefore, may be disclosed to the public.

1. Introduction

Ozone-depleting substances (ODS) are being phased out of production in response to a series of 

diplomatic and legislative efforts that have taken place over the past decade, including the Montreal 

Protocol and the Clean Air Act Amendments of 1990 (CAAA). The U.S. Environmental Protection 

Agency (EPA), as authorized by Section 612 of the CAAA, administers the Significant New Alternatives 

Policy (SNAP) Program, which identifies acceptable and unacceptable substitutes for ODS in specific 

end-uses based on assessment of their health and environmental impacts. 

EPA’s decision on the acceptability of a substitute is based on the findings of a screening assessment of 

potential human health and environmental risks posed by the substitute in specific applications. EPA has 

already screened a large number of substitutes in many end-use applications within all of the major ODSusing sectors, including refrigeration and air conditioning, solvent cleaning, foam blowing, aerosols, fire 

suppression, adhesives, coatings and inks, and sterilization. The results of these risk screens are presented 

in a series of Background Documents that are available in EPA's docket.

The purpose of this risk screen is to supplement EPA’s Background Document on the fire suppression 

and explosion protection sector (EPA 1994a) (hereinafter referred to as the Background Document). This 

risk screen discusses potential human health and environmental risks posed by KSA when used as a 

flooding agent in normally unoccupied spaces as a replacement for Halon 1301. Table 1 provides the 

composition of KSA prior to and after activation and Table 2 provides the maximum concentrations of 

impurities found in KSA.

Table 1: Composition of KSA, Pre- and Post Activation

Constituent Chemical 

Formula CAS # Weight 

Percent
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Table 2: Maximum Concentrations of Impurities in KSA

Impurity Chemical 

Formula

Maximum 

Concentration

Section 2 of this risk screen summarizes the results of the risk screen for the proposed substitute. The 

remainder of the risk screen is organized into the following sections:

 Section 3: Atmospheric Assessment; 

 Section 4: Occupational Exposure Assessment;

 Section 5: General Population Exposure Assessment; 

 Section 6: Volatile Organic Compound Assessment; and

 Section 7: References.

2. SUMMARY OF RESULTS

KSA is recommended for SNAP approval as a flooding agent in normally unoccupied spaces. Given that 

proper training will be provided to personnel and that appropriate personal protective equipment (PPE) 

and proper procedures according to the MSDS will be used during manufacturing, installation, 

maintenance, and disposal activities, no significant risks to workers or the general population is 

anticipated. Section VIII of the Occupational Safety & Health Administration (OSHA) Technical Manual 

(OSHA 1999) should be consulted for information on selecting the appropriate types of PPE. The risk 

screen indicates that the use of the proposed substitute in normally unoccupied spaces will be less harmful

to the atmosphere than the continued use of Halon 1301. Additionally, the risk to the general population 

is expected to be below levels of concern for non-cancer risks. 

3. ATMOSPHERIC ASSESSMENT

This section presents an assessment of the potential risks to atmospheric integrity posed by the use of 

KSA as a flooding agent in normally unoccupied areas. According to the applicant, the active ingredients 

for this technology are solids both before and after accidental dispersion; therefore, the ozone-depleting 

potential (ODP), global warming potential (GWP) and the atmospheric lifetime (ALT) are all zero (Kidde

SNAP Submission 2008). Accordingly, use of KSA is not expected to pose any significant adverse 

atmospheric impacts.

4. OCCUPATIONAL EXPOSURE ASSESSMENT

The potential for personnel exposure during manufacture, installation and maintenance, and clean-up are 

examined in this section. The discharge scenarios discussed are assumed to occur accidentally and not as 

the result of a fire. 
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4.1. Occupational Exposure During Manufacture

As described by the submitter, workers could be exposed to KSA during manufacture, sometimes for 

extended periods of time. Due to the highly respirable nature of the substitute, and the long periods of 

exposure, manufacturing employees should wear appropriate PPE, such as protective clothing, gloves, 

goggles, and respiratory protection, selected in accordance with the OSHA Technical Manual (OSHA 

1999). Additionally, rooms in which personnel are working should be well ventilated with a local 

exhaust system and an eye wash fountain and quick drench facilities must be close to the production area.

In the case of an accidental spill, workers should immediately vacate the premises and follow the first aid 

guidelines listed in the MSDS. The recommendations for clean-up discussed in Section 4.3 should be 

followed. 

4.2. Occupational Exposure During Installation and Maintenance

The post-activation product is entirely particulate, and as indicated by the submitter, of such a size which

makes it highly respirable and able to reach the extrathroracic, tracheo-bronchial, and pulmonary regions 

of the respiratory system (Kidde SNAP Submission 2008; EPA 1994b). As such, proper PPE should be 

used. In the following sections, recommended PPE for exposure at installation and maintenance, are

detailed. The main constituent of the substitute, despite having low toxicity, can also pose a human health 

risk because it can raise blood pH if inhaled in sufficient quantities. However, blood pH modeling 

indicates that the levels of this constituent in KSA are not expected to pose a significant health risk (see 

Section 4.2.1.1). 

4.2.1 Installation and Maintenance

When the KSA system is activated, there is little warning time before the system disperses. Given the 

fine particle size of the proposed substitute, the high levels to which personnel may be exposed (Table 3)

and the short warning time, personnel performing installation or maintenance work should wear

appropriate PPE (i.e., protective clothing, goggles, gloves and respiratory protection), according to the 

OSHA Technical Manual . Installation personnel should also receive training so as to minimize the risk 

for accidentally discharging the system while performing installation. 

Table 3: Maximum Expected Exposure Levels and

Toxicological Thresholds for KSA Constituents and Impurities

Constituent

Occupational 

Exposure

(mg/m3)

IDLH a

(mg/m3)

NIOSH 

REL

a

(mg/m3)

OSHA 

PELa

(mg/m3)

NA = Not available

a Source: (NIOSH 2007).
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4.2.1.1 Exposure After Release

The proposed powdered extinguishing agent contains soluble particles of a compound that, when inhaled, 

may deposit in the respiratory tract. These soluble particles could potentially cross the biological 

membranes of the respiratory system and enter the systemic circulation. The absorption of a large amount 

of this constituent could potentially have an impact on the body’s acid-base balance. To determine the 

potential impact on the body’s acid-base balance of exposure to this constituent via inhalation, the effect 

of an accidental release of KSA was modeled.

Using information provided by the submitter, a reasonable worst-case release scenario was constructed in 

which a release of the proposed substitute occurs, exposing maintenance personnel to the maximum 

design concentration provided by the submitter. The following assumptions were made regarding the 

constituent that could potentially impact the body’s acid-base balance:

 all constituent particles (i.e., 100%) are small enough to be respirable (EPA 1994b);

 all of the inhaled constituent is soluble and enters the systemic circulation;

 exposed to this level of particulate matter, the room occupant’s breathing pattern will become 

shallow and rapid, with a respiratory rate of 40 breaths per minute at a tidal volume of 150 

mL/breath1(Sherwood 2005); and

 the human body has 70 mL blood/kg; therefore, a 70 kg male has 4.9 L of blood and a 57 kg 

female has 4.0 L of blood (Guyton and Hall 1996).

Given the assumptions listed above, the model indicates that at the maximum blood pH resulting from 

accidental release of KSA in the protected space, no significant adverse health effects are expected. The 

body has compensatory mechanisms including a decrease in the respiratory rate, which increases blood 

levels of CO2, forming carbonic acid that neutralizes the increased blood and extracellular pH. In 

addition, the kidneys increase blood filtration. Post-exposure oral application of 8-12 ounces of 

electrolyte-containing fluids, such as orange juice or a sports drink, which contain high levels of 

potassium, will help restore the normal physiological electrolyte balance, and will help restore kidney 

function. Additionally, as the kidneys will be working harder than usual, personnel should also increase 

their water intake for about a week after exposure.

4.3. Post-Activation Clean-Up

Only one application in which KSA may be used has an audible horn warning of impending discharge. 

Therefore, unless there is a witness to the KSA system discharge or there is some other means of 

determining the exact time of discharge (e.g., security camera record), clean-up workers would not know 

when the system had discharged and thus would not know when all particles from the system would have

settled. Prior to cleanup, the air exchange rate in the room should be increased in order to aerate the space 

and reduce humidity. Also, spraying a dust suppressant compound should minimize the re-circulation of 

nuisance dust particles. 

To minimize exposure to dust particles, it is recommended that all workers entering the protected volume 

to clean-up after activation wear appropriate PPE (i.e., protective clothing, goggles, gloves and respiratory 

protection) in accordance with the OSHA Technical Manual (OSHA 1999).

 

1 This is equal to a respiratory rate of 0.36 m3

/hr.
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The contents removed from the protected volume should be disposed of according to federal, state and 

local regulations. By adhering to safety guidelines mentioned above in Section 4, the potential for 

excessive worker exposures to KSA during post-activation cleanup will be unlikely.

5. GENERAL POPULATION EXPOSURE ASSESSMENT

This section screens potential risks to the general population from exposure to ambient air releases of 

KSA constituents. Factory releases (occurring during manufacture) and on-site releases (those occurring 

at the end-use) are examined in this section. By following existing regulations, factory or on-site releases 

are not likely to pose a significant threat to ambient air, surface water, or solid waste. Consequently, use 

of KSA is not expected to pose significant risk to the general population. 

5.1. Ambient Air

All manufacturing occurs in a facility with certain engineering controls in place, so minimal release to the 

ambient air is expected. Installation and servicing occur in very large sites, so releases in such locations

are expected to be well below the acceptable exposure limits. Therefore, air emissions associated with the 

manufacture and use of KSA are not of concern to the health of the general population. 

5.2. Surface Water

If all the solid waste settles onto the floor of the unoccupied space and is removed from the site according 

to federal, state, and local requirements, the KSA components are not likely to settle into nearby streams 

or ponds. 

5.3. Solid Waste 

If all spilled and settled material in the manufacturing facility and all on-site releases are cleaned up and 

disposed of according to federal, state, and local requirements, no release to the environment is expected. 

6. VOLATILE ORGANIC COMPOUND ASSESSMENT

The KSA constituents are not considered VOCs for purposes of local air quality. 

7. REFERENCES

EPA. 1994a. Risk Screen on the Use of Substitutes for Class I Ozone-Depleting Substances: Fire 

Suppression and Explosion Protection (Halon Substitutes). Stratospheric Protection Division. March 

1994. 

EPA. 1994b. Methods for Derivation of Inhalation Reference Concentrations and Application of 

Inhalation Dosimetry. Office of Research and Development, U.S. Environmental Protection Agency. 

EPA/600/8-90/066F. October 1994. Available online at 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=71993. 

Guyton, A.C., MD and Hall, J.E., PhD. 1996. Textbook of Medical Physiology 9th ed. W.B. Saunders 

Co., Philadelphia. p. 299.

Kidde SNAP Submission. 2008. Significant New Alternatives Policy Program Submission to the United 

States Environmental Protection Agency, July 2008. 

NFPA. 2006. NFPA 2010: Standard for Fixed Aerosol Fire-Extinguishing Systems. National Fire 

Protection Agency. 
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NIOSH. 2007. NIOSH Pocket Guide to Chemical Hazards. Department of Health and Human Services, 

Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health. 

Publication No. 2005-149. September 2007.

OSHA. 1999. OSHA Technical Manual. Department of Labor. Occupational Safety and Health 

Administration. January 20, 1999. Available online at 

<http://www.osha.gov/dts/osta/otm/otm_toc.html>.

Sherwood, L. 2005. Fundamentals of Physiology: A Human Perspective. Brooks Cole, 2005. Viewable 

online at: < http://books.google.com/books?id=4INVi-m7gX8C&>.