HETA 91-0230-2543 NIOSH INVESTIGATORS:

NOVEMBER 1995 Gregory M. Kinnes, M.S., C.I.H.

INTERNATIONAL ASSOCIATION Steven Short, D.O.

 OF FIRE FIGHTERS (IAFF) Scott Deitchman, M.D.

HENDERSON, NEVADA

I. SUMMARY

On May 16, 1991, the National Institute for Occupational Safety and Health (NIOSH)

received a request for a health hazard evaluation (HHE) from the International

Association of Fire Fighters (IAFF), on behalf of members in the Clark County,

Nevada, and the City of Henderson, Nevada, fire departments. Fire fighters in these

departments responded on May 6, 1991, to a chlorine leak at the Pioneer Chlor Alkali

plant located just outside the Henderson city limits. The IAFF reported that several fire

fighters who responded to this incident had developed respiratory symptoms that they

attributed to chlorine exposure.

On May 28-29, 1991, three weeks after the incident, NIOSH investigators held joint

meetings with representatives from the Henderson Fire Department (HFD) and the

Clark County Fire Department (CCFD) management, the City of Henderson, and the

two IAFF locals; in addition, separate meetings were conducted with representatives of

the Clark County Health District and Pioneer Chemical. Private interviews were

conducted with 10 HFD fire fighters and the physicians who had treated fire fighters

during/after the incident. Information from these meetings, various records, and

interviews were used to reconstruct events and procedures used during the incident

response and to review incident medical care and fire fighter symptoms. Six months

following the chlorine leak of May 6, 1991, 150 medical questionnaires were sent by

mail to the involved police and fire departments for completion by workers potentially

exposed during the incident.

According to available figures, approximately 200 fire fighters were involved in the

response to this emergency. Eleven fire fighters were hospitalized or held for

observation, and several others were reportedly injured by exposure to the chlorine. 

Many of the fire fighters complained of skin irritation and respiratory difficulty, even

though they were wearing self-contained breathing apparatus (SCBA) and structural fire

fighter’s protective clothing. Although a Community Awareness and Emergency

Response (CAER) plan had previously been devised by the chemical manufacturers at

the industrial complex where the Pioneer plant is located and the local emergency

response units, this plan was reportedly not activated. Air monitoring performed by the

Clark County Health District (CCHD) indicated that chlorine concentrations during the

incident ranged from less than 0.2 to 17 parts per million (ppm). Due to the weather

conditions, the chlorine plume was unpredictable, and the command post was relocated

on four occasions. Representatives from the responding agencies indicated that there

were several instances of coordination and communication difficulties. Reported

This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific facility evaluated and may not be universally

applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved.

Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports

This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific facility evaluated and may not be universally

applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved.

Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports

This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific facility evaluated and may not be universally

applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved.

applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved.

Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports
Several fire fighters who responded to this incident experienced adverse health effects

from chlorine gas exposure, including hospitalization and persistent respiratory

symptoms. Many of the fire fighters complained of skin irritation and respiratory

difficulty, even though they used SCBA’s and their structural fire fighter’s protective

gear. The questionnaire data indicated that the duration and severity of respiratory

symptoms tended to increase with the proximity to the leak site despite the use of

respirators. However, the low response rate to the questionnaire survey and potential

selection biases, limited the ability to further generalize the questionnaire data. 

Possible explanations for the occurrence of symptoms include the improper fit of, or

delays in donning of, respiratory protection and the use of structural fire fighter’s

protective gear instead of appropriate chemical protective clothing. 

Recommendations regarding the response to this incident are presented in Section

VIII of this report.

concerns and problems encountered during the incident response included delays in the

response of the hazardous materials teams, deployment, and use of appropriate personal

protective equipment; the lack of a common communications frequency for all

participating agencies; and the need for appropriate decontamination procedures.

NIOSH received a total of 59 completed questionnaires: 42 from fire fighters and 17

from individuals other than fire fighters. Most fire fighters responding to the

questionnaire reported inhaling chlorine gas, even though most used respirators during

the incident. Symptoms included coughing, tightness in the chest, wheezing, tearing

eyes, sore throat, and/or headache after exposure to chlorine. Among the questionnaire

respondents, symptom occurrence and severity were greatest among those stationed at

the leak site. The duration of symptoms also appeared to increase with proximity to the

chlorine leak. Symptom resolution was faster among respondents who did not wear

respirators, which may suggest that the intensity of exposure experienced, the personal

perception of respirator need, and improper respirator use were related to symptom

duration.

KEYWORDS: SIC 9224 (Fire Protection), fire fighters, firefighters, chlorine,

respiratory symptoms, police, incident command system, health effects, self-contained

breathing apparatus.
Page 3 - Health Hazard Evaluation Report No. 91-0230

II. INTRODUCTION

On May 16, 1991, the National Institute for Occupational Safety and Health (NIOSH)

received a request for a health hazard evaluation (HHE) from the International

Association of Fire Fighters (IAFF), on behalf of members in the fire departments of

Clark County, Nevada (CCFD), and the City of Henderson, Nevada (HFD). Fire

fighters in these departments responded on May 6, 1991, to a chlorine leak at the

Pioneer Chlor Alkali plant, which is located in a large industrial complex adjacent to

the Henderson city limits but within Clark County’s jurisdiction. The IAFF reported

that several fire fighters had developed respiratory symptoms attributed to chlorine

exposure. The IAFF requested that NIOSH evaluate the adequacy of procedures

followed during the fire departments' response to this leak and to evaluate the medical

care and monitoring provided to all exposed fire fighters.

On May 28-30, 1991, NIOSH investigators conducted an initial site visit to the HFD in

Henderson and the CCFD in Las Vegas. During the visit, the NIOSH investigators held

meetings with representatives from the fire departments' management, the City of

Henderson, and IAFF locals 1883 and 1908. In addition, separate meetings were

conducted with representatives of the Clark County Health District and Pioneer

Chemical. Private interviews were conducted with 10 Henderson fire fighters. 

Physicians who had treated fire fighters were interviewed by telephone, and additional

information, including incident, medical, and compensation reports, was collected to

reconstruct the events during the chlorine leak and subsequent health effects. After the

initial site visits, the NIOSH investigators designed and distributed questionnaires to

fire fighters involved with this incident response to investigate the respiratory

protection of workers and respiratory symptoms related to the incident.

III. BACKGROUND

On the morning of May 6, 1991, beginning around 1:10 a.m., a leak developed in a

chlorine transfer pipe at the Pioneer Chlor Alkali Plant located at the Basic

Management Incorporated (BMI) complex in Henderson, Nevada. The BMI complex is

a private organization of four companies (Timet, Stouffer, Kerr McGee, and Pioneer)

that operate chemical and fuel production facilities adjacent to Henderson, Nevada. 

The chlorine leak occurred in a pipe that connects a chlorine storage tank to a heat

exchanger. Chlorine is separated from aqueous solutions of sodium chloride,

commonly called brine, by electrochemical decomposition. The resultant chlorine is

cooled in a heat exchanger and is then piped to a storage tank. A transfer pipe, leading

to a chlorine storage tank containing approximately 150 tons of liquid chlorine, had

corroded and developed a one-inch hole, which began leaking the chlorine gas. The
Page 4 - Health Hazard Evaluation Report No. 91-0230

leak resulted in the uncontrolled release of chlorine gas, which eventually spread

beyond the boundaries of the plant. At 2:14 a.m., the CCFD was notified by a citizen's

complaint of a noxious odor.

Although a Community Awareness and Emergency Response (CAER) plan had been

devised by the chemical manufacturers at the BMI complex and the local emergency

response units, this plan was reportedly not activated by the Pioneer Chlor Alkali plant

staff. Since this plan had not been activated, and since the CCFD receives

approximately 50 complaint calls of this type per year involving the BMI complex, the

first CCFD fire fighters to arrive at the BMI complex stopped at the guard shack to

inquire about the presence of a leak. A team of two fire fighters was questioning the

Pioneer personnel at the guard shack when an alarm sounded as chlorine from the leak

reached the guard shack. The two fire fighters were immediately overcome by the

chlorine, which resulted in coughing, tearing of the eyes, and bloody sputum. Due to

the proximity of the HFD to the BMI complex, the CCFD requested mutual aid from

the HFD, which dispatched a rescue squad. The rescue squad assisted the downed fire

fighters and transported them to a nearby hospital. Units from both fire departments

arrived to assist, and a team of two fire fighters was sent into the site with selfcontained breathing apparatus (SCBA) to find people affected by the cloud of gas and

to investigate the source of the leak.

Concern for the general population led to a discussion of an evacuation of nursing

homes, hospitals, and residential homes, and additional units of fire fighters were

dispatched to the immediate area surrounding the leak. The evacuation of citizens from

residential areas and municipal buildings was eventually ordered as the chlorine plume

migrated outside the borders of the BMI complex. Twenty schools in the Clark County

School District were closed. According to available figures, approximately 200 fire

fighters were involved in the response to this emergency, with fire fighters from Clark

County, Henderson, Las Vegas, Nellis Air Force Base, and Boulder City participating. 

The emergency response units initially located a command post site at a power plant

near the entrance to Pioneer Chemical. As the chlorine gas spread, fire fighters were

forced to successively relocate the command post first to a convenience store parking

lot, then to a Henderson Fire Department station, and finally to a race track. The final

command post at the race track was located two miles southeast of the BMI complex. 

Wind changes occurring during the night resulted in chlorine contamination beyond the

original area. Fire fighters manning rescue vehicles were exposed in previously safe

decontamination areas when they removed their SCBAs and were exposed to chlorine

gas which had accumulated in spaces in their vehicles during rescue operations. Eleven

fire fighters were hospitalized or held for observation as a result of chlorine gas

exposure. Police officers who were participating in traffic control or evacuations were

also exposed during the performance of their tasks, as were corrections officers who
Page 5 - Health Hazard Evaluation Report No. 91-0230

evacuated inmates, and communications center workers when chlorine gas

contaminated municipal buildings. A list of the responding agencies and the number of

employees involved is included in Table I.

Beginning at 5:00 a.m., the Clark County Environmental Health staff began to collect

air samples using colorimetric indicator tubes throughout the cities of Henderson,

Green Valley, and East Las Vegas. During the collection, respiratory protection was

worn because concentrations of chlorine gas exceeding 0.5 parts per million (ppm) were

routinely encountered. The results of these air samples are listed in Table II. 

Throughout the morning, the chlorine concentrations were relayed back to the

command post. At 8:05 a.m., a flange was placed in the leaking pipe, shutting off the

leak. With the flange applied, the sun rising, and the wind velocity increasing, the

chlorine cloud dissipated within 30 minutes.

The Pioneer Chlor Alkali Company estimated that 70 to 100 tons of chlorine were

released. There was immediate concern from community residents about the incident,

with the odor still detectable, and the major highways closed until 10:30 a.m.. Many

residential areas were blanketed by the cloud, and the majority of calls to 911

dispatchers related to complaints of community residents having difficulty breathing. 

Aid stations, where oxygen was available, were set up around the community. On the

day of the leak, a total of 317 medical reports were filed in local hospitals relating to the

incident.

Liquid chlorine was not present at the site following the leak; only chlorine vapor had

escaped. Regardless of this, fire fighters involved in the immediate area were hosed

down with water following the incident, and 18 sets of fire fighter’s turnout gear were

“decontaminated.” This decontamination of the turnout gear was performed mostly by

commercial washing. Several fire fighters on the scene were sent to the hospital for

evaluation, including 17 from Henderson and 28 from Clark County. Four fire fighters

from Clark County were admitted to a hospital, and six others were held overnight for

observation. None of the fire fighters from Henderson were hospitalized; however, one

was held several hours in the emergency room for observation before being released. 

Some city employees also reportedly developed symptoms the day after the incident

when they reported to work in municipal buildings and were allegedly exposed to

residual chlorine still present in the buildings.

IV. METHODS

On May 28-29, 1991, three weeks after the incident, NIOSH investigators met with the

union representatives and fire chiefs from the Clark County and Henderson City fire
Page 6 - Health Hazard Evaluation Report No. 91-0230

departments, with representatives from the Clark County Health District and the City of

Henderson being present. This meeting was arranged to discuss the incident

chronology, the extent of the chlorine leak, procedures used during the response, and

the effects of the leak on the various fire fighters that were involved. The NIOSH

investigators spent additional time during these two days interviewing various fire

fighters who were at the incident and reviewing records obtained by the City of

Henderson and Clark County relating to the incident. These included incident reports

and witnesses' statements that were attached to 110 compensation reports for employees

of the City of Henderson. Physicians who had treated fire fighters were also

interviewed by telephone. This information was used to reconstruct events and

procedures used during the incident response, to evaluate the fire fighters’ symptoms,

and to review the medical care and monitoring provided to all exposed fire fighters.

Based on the information obtained from the interviews with the fire fighters, the

medical records that were reviewed, and the discussion with the physicians caring for

the exposed individuals, the NIOSH medical investigators designed a questionnaire to

investigate the respiratory protection of workers and respiratory symptoms related to the

incident. Six months following the chlorine leak, questionnaires were sent by two

separate mailings to the involved police and fire departments for distribution to

approximately 150 of their employees who were at the incident scene. The

questionnaire was designed to investigate the relationship of: 1) the location of the

individual during the leak; 2) the time the individual was exposed to the gas;

3) whether, and what type of, respiratory protection was used; 4) how much time the

individual took to put on respiratory protection; and 5) the type, severity, and duration

of respiratory symptoms following the leak. The questionnaire requested information

on coughing, chest tightness, wheezing, tearing eyes, sore throat, headache, runny nose,

and sneezing. Additionally, respondents were asked to describe symptoms not

specifically listed. A copy of the questionnaire is included in the Appendix.

V. EVALUATION CRITERIA

Fire fighters work in varied and complex environments that increase their risk of onthe-job death and injury. Every day, fire fighters in the United States are injured in the

line of duty, some so severely that they can never return to work.1

 In 1993, according to

the Bureau of Labor Statistics, fire fighters incurred a relatively small number of

fatalities (39), as compared to other dangerous occupations, but their rate of fatal injury

on the job, 16 fatalities per 100,000 employed, was three times the national rate and was

highest among the protective service occupations.2

 In addition, there were 101,500 fire

fighters injured in the line of duty in 1993.1

 According to 1992 National Safety Council

statistics, the occupational injury and illness incidence rate for fire fighters was 8.2

cases per 100 full-time employees, with 3.5 cases per 100 employees involving days
Page 7 - Health Hazard Evaluation Report No. 91-0230

away from work and deaths.3

 Fire fighters face many health hazards, including

inhalation of a wide variety of toxic combustion products; chemical exposures by

inhalation and direct skin and eye contact; physical hazards, including heat, cold, noise,

and falling objects; and exposure to carcinogenic chemicals or combustion products. In

over 200 residential fires in Boston, air monitoring (which focused on a small fraction

of the possible combustion products) found varying airborne concentrations of carbon

monoxide, carbon dioxide, hydrogen cyanide, benzene, nitrogen dioxide, hydrogen

chloride, and acrolein.4,5 Other toxic components of smoke can include ammonia,

acrylonitrile, halogen acids, sulfur dioxide, aldehydes, isocyanates, methylene chloride,

particulates, and hydrocarbons.6-8

Exposures to respiratory irritants such as acrolein, hydrogen chloride, and nitrogen

dioxide may lead to acute and chronic respiratory problems. Disability due to

pulmonary disease has long been recognized as a potential work-related hazard for fire

fighters. There is an increasing concern about a fire fighter's exposures to carcinogens

released from the combustion of synthetic materials used in building construction.9

This concern has been compounded by mortality and morbidity studies of fire fighters,

which, although they have produced inconsistent evidence, have raised the possibility of

increased risks of cardiovascular disease, respiratory disease, and cancers of the

nervous, hematopoietic/lymphatic, respiratory, and gastrointestinal systems, which may

be attributable to exposures to the components of smoke.10-25 Several recent studies

have suggested an increased risk of brain cancer among Washington fire fighters; brain,

prostrate, colon, and lung cancer among Los Angeles fire fighters; and digestive tract

cancers.19,21,23,26

As a guide to the evaluation of the hazards posed by workplace exposures, NIOSH field

staff employ environmental evaluation criteria for the assessment of a number of

chemical and physical agents. These criteria are intended to suggest levels of exposure

to which most workers may be exposed up to 10 hours per day, 40 hours per week for a

working lifetime without experiencing adverse health effects. It is, however, important

to note that not all workers will be protected from adverse health effects even though

their exposures are maintained below these levels. A small percentage may experience

adverse health effects because of individual susceptibility, a pre-existing medical

condition, and/or a hypersensitivity (allergy). In addition, some hazardous substances

may act in combination with other workplace exposures, the general environment, or

with medications or personal habits of the worker to produce health effects even if the

occupational exposures are controlled at the level set by the criterion. These combined

effects are often not considered in the evaluation criteria. Also, some substances are

absorbed by direct contact with the skin and mucous membranes, and thus potentially

increase the overall exposure. Finally, evaluation criteria may change over the years as

new information on the toxic effects of an agent become available.
Page 8 - Health Hazard Evaluation Report No. 91-0230

The primary sources of environmental evaluation criteria for the workplace are: 

1) NIOSH recommended exposure limits (RELs),27 2) the American Conference of

Governmental Industrial Hygienists' (ACGIH) Threshold Limit Values (TLVsTM)28, and

3) the U.S. Department of Labor, Occupational Safety and Health Administration

(OSHA) permissible exposure limits (PELs).29 In July 1992, the 11th Circuit Court of

Appeals vacated the 1989 OSHA PEL Air Contaminants Standard. OSHA is currently

enforcing the 1971 standards which are listed as transitional values in the current Code

of Federal Regulations; however, some states operating their own OSHA approved job

safety and health programs continue to enforce the 1989 limits. NIOSH encourages

employers to follow the 1989 OSHA limits, the NIOSH RELs, the ACGIH TLVs, or

whichever are the more protective criterion. The OSHA PELs reflect the feasibility of

controlling exposures in various industries where the agents are used, whereas NIOSH

RELs are based primarily on concerns relating to the prevention of occupational

disease. It should be noted when reviewing this report that employers covered by

OSHA are legally required to meet those levels specified by an OSHA standard and that

the OSHA PELs included in this report reflect the 1971 values.

In most cases, these environmental evaluation criteria are listed as time-weighted

average (TWA) exposures. A TWA exposure refers to the average airborne

concentration of a substance during a normal 8- to 10-hour workday. Some substances

have recommended short-term exposure limits (STEL) or ceiling values which are

intended to supplement the TWA where there are recognized toxic effects from higher

exposures over the short-term. For the fire fighters responding to this chlorine leak, a

STEL would be the most applicable criterion. A STEL is the concentration to which

workers can be exposed continuously for a short period of time without suffering from: 

1) irritation, 2) chronic or irreversible tissue damage, or 3) narcosis of sufficient degree

to increase the likelihood of accidental injury, impair self-rescue or materially reduce

work efficiency, and provided that the daily TWA is not exceeded.28 STELs are

recommended only where toxic effects have been reported from high short-term

exposures in either humans or animals. A STEL is defined as a 15-minute TWA

exposure which should not be exceeded at any time during a workday even if the 8-hour

TWA is not exceeded. Exposures above the TWA up to the STEL should not be longer

than 15 minutes and should not occur more than four times per day. There should be at

least 60 minutes between successive exposures in this range.28

In the event of hazardous materials incidents such as the chlorine leak, the use of the

immediately dangerous to life or health (IDLH) criterion should be considered. IDLH

concentrations represent the maximum concentration from which, in the event of

respirator failure, one could escape within 30 minutes without a respirator and without

experiencing any escape-impairing or irreversible health effects.30 These values were

determined during the Standards Completion Program, a joint effort by NIOSH and the
Page 9 - Health Hazard Evaluation Report No. 91-0230

Department of Labor to develop supplemental requirements for the environmental

exposure standards adopted by OSHA in 1971, but only for the purpose of respirator

selection.

Chlorine and Pulmonary Toxicity

Chorine is the most abundant halogen and among the most reactive of all elements.31

Chlorine gas consists of molecules of two chlorine atoms, thus its chemical

abbreviation Cl2. At room temperature, chlorine is a greenish-yellow gas that has a

conspicuous, pungent odor, and is 2.5 times heavier than air.32,33 The range of reported

odor thresholds for chlorine is 0.03 to 3.5 ppm; however, because of olfactory fatigue,

odor does not always serve as an adequate warning of exposure. There is some

evidence that olfactory fatigue may occur at low concentrations and that a tolerance is

built-up in exposed workers.34 The acute effects of exposure to chlorine depend on the

duration of exposure and the concentration of the chlorine, with effects being more

severe following longer exposures and higher concentrations. Symptoms typically

begin moments after exposure. Chlorine is irritating to the eyes and skin, producing

excessive tearing (lacrimation) and dermatitis upon contact.32,35,36 Mild mucous

membrane irritation may occur at 0.2 to 16 ppm, eye irritation occurs at 7 to 8 ppm,

throat irritation at 15 ppm, and coughing at 30 ppm. A level of 1000 ppm is fatal after a

few deep breaths.34 Other studies have shown that at least some subjects can develop

eye irritation, headache, and coughing at concentrations as low as 1 to 2 ppm.32 The

long-term effects of chlorine exposure depend on the amount of damage to the lungs.37

Upon absorption into the tissue fluids, chlorine undergoes a series of reactions to

produce hydrochloric acid (HCl), hypochlorous acid (HOCl), and nascent oxygen (O). 

Each of these chemicals damages biologic tissue.38 The level of exposure and intensity

of exposure determines the degree of inflammatory reaction that develops in the

airways.39 The initial mucous membrane injury is probably due to the oxidizing effect

of nascent oxygen, liberated by a combination of water and the chlorine gas. Then,

hydrochloric acid production causes further irritation and exacerbates the initial injury.40

Severe, acute effects from accidental exposures to chlorine gas have been documented

since World War I, when 1,843 of 70,742 total U.S. military casualties resulted from

gassing by chlorine.41 Among the 838 cases studied, there were 28 deaths, 4 of which

were attributed to "late" sequelae of gassing: bronchopneumonia, lobar pneumonia,

purulent pleurisy, and tubercular meningitis. Nine persons were discharged from the

military because of disabilities precipitated by gassing, which included pulmonary

tuberculosis, a flare-up of former lung disease, bronchitis, pleurisy, tachycardia,

dyspnea, and nephritis. Thirty-nine others were disabled at the time of discharge with

similar conditions due to gassing.42 Health effects resulting from severe acute
Page 10 - Health Hazard Evaluation Report No. 91-0230

exposures have been reported after several transportation and industrial accidents.36

These exposures have caused cough, dyspnea (shortness of breath), cyanosis (a blue

discoloration of skin and mucous membranes due to inadequate transfer of oxygen from

the lungs to the blood), tracheobronchitis, hypoxemia (decreased oxygen in the blood),

obstructive and restrictive abnormalities of pulmonary function, pulmonary congestion

and edema developing after a latent period of several hours, pneumonitis, and deaths. 

In most of these studies, the respiratory distress generally subsided within days after

exposure, and pulmonary function returned to normal after several months, with some

exceptions among those with preexisting respiratory conditions. However, in one

study, the pulmonary effects cleared within three months, except for four chlorine

workers who still showed reduced airway flow and mild hypoxemia after 12 to 14

months.43 Another study found decreased lung capacity in a number of workers three

years after a moderately severe acute exposure.44

Several epidemiologic studies in chemical plants, pulp and paper mills, and chlor-alkali

plants have shown no significant dose-response correlations between chlorine

exposures and specific pulmonary function tests, and no evidence of permanent lung

damage.41 NIOSH concluded in 1976 that there was not then enough evidence to

determine whether there is a potential for chronic impairment of pulmonary function

following acute or chronic chlorine exposure.36

The upper and lower respiratory tract mucosa is an extremely effective barrier to toxic

gas insults. At times this protective barrier is overcome by an especially high level of

exposure, resulting in mucosal irritation, bronchitis, bronchoconstriction,

laryngotracheobronchitis, noncardiogenic pulmonary edema, and death. The respiratory

system has the potential to recover completely after such an insult, and in most cases

this is to be expected. Sometimes though, long-term sequelae, such as chronic

bronchitis, bronchiectasis, bronchiolitis obliterans, emphysema, or interstitial fibrosis,

may result. Brooks and colleagues initially described ten cases of airway injury that

followed transient exposure to highly concentrated respiratory irritants. This “reactive

airway dysfunction syndrome” (RADS) was characterized by coughing, shortness of

breath, and wheezing.45 In all cases, symptoms developed within 12 to 24 hours of

exposure and persisted for at least 3 months.

Acute symptoms following the inhalation of irritant gases like chlorine are felt to be a

result of airway inflammation. Transbronchial lung biopsies performed in two of the

workers in Brooks' study 9 and 33 months after the injury showed respiratory epithelial

injury with a chronic unspecific airway inflammatory response. Several other

investigations have suggested that inflammation is responsible for a change in the

airways responsiveness, possibly due to the superficial location of irritant subepithelial

receptors, and the associated bronchial inflammatory response that might occur after

heavy irritant exposure.46,47
Page 11 - Health Hazard Evaluation Report No. 91-0230

Presently, the OSHA PEL for chlorine is 1 ppm as a ceiling limit. The NIOSH REL

and ACGIH TLV for chlorine are 0.5 ppm as a TWA; however, the REL is based on a

10-hour workday while the TLV is based on an 8-hour workday. In addition, both

NIOSH and the ACGIH have established a 1 ppm 15-minute STEL. The IDLH for

chlorine is 10 ppm and is based on acute inhalation toxicity data in humans.48-50

VI. FINDINGS AND DISCUSSION

A. Organizational and Environmental Aspects

The initial response to the noxious odor complaint was made by the CCFD

Battalion 3. When this battalion arrived on the scene, there was reportedly no

detectable chlorine odor or observable plume. The fire fighters proceeded to the

guard shack to question employees that had gathered. As they were questioning

the employees about the presence of a chlorine leak, an alarm sounded when

chlorine reached the guard shack. The fire fighters of Battalion 3 were not able to

don their SCBAs, which were located in their vehicle, before they were overcome. 

The injured fire fighters were then transported off-scene and an incident command

system was initiated. Although a Community Awareness and Emergency

Response (CAER) plan had previously been devised by the chemical

manufacturers at the BMI complex and the local emergency response units, this

plan was reportedly not activated by the Pioneer Chlor Alkali plant staff.

There were several agencies and companies that responded in some capacity to

this chlorine leak. Table I lists the agencies that responded to the incident, the

number of employees involved, and the number hospitalized. For some of the

responding agencies, the total number of employees involved was not available. 

These latter agencies were primarily involved with support activities and not with

the direct response. As noted in Table I, the employee numbers for these agencies

were either estimated or not provided. Employees of the City of Henderson and

Clark County were requested to file an accident report, and these were reviewed

and used to compile the information for these agencies.

During the incident, the Clark County Health District (CCHD) performed air

monitoring to track the chlorine plume and coordinated their efforts with the

incident command. Due to the weather conditions, the chlorine plume was

unpredictable. This resulted in the command post being relocated on three

occasions. The CCHD began air monitoring at approximately 5:30 a.m. and

continued until the end of incident. The airborne chlorine concentrations

(Table II) were determined using colorimetric indicator sampling tubes and ranged
Page 12 - Health Hazard Evaluation Report No. 91-0230

from less than 0.2 to 17 ppm. Five of the six samples taken from 8:25 a.m. to the

end of the incident showed no detectable chlorine concentrations; one sample

collected at 9:10 a.m. indicated a chlorine concentration of 3 ppm. The remaining

eight samples were all collected before 8:25 a.m. and had chlorine concentrations

ranging from 0.5 to 17 ppm. One concentration exceeded the 10 ppm IDLH, and

six others equaled or exceeded the 1 ppm STEL. All these samples were collected

using colorimetric indicator tubes for chlorine at locations outside of the BMI

complex. These colorimetric indicator tubes are not as accurate as other air

sampling methods and may be subject to interferences. Therefore, the actual

concentrations encountered by the response personnel may have been higher or

lower than those measured, depending on their locations during the incident.

During the meetings and private interviews conducted as part of the investigation,

several individuals expressed concern about the preparedness and response of the

different fire departments which were involved in the incident. Participants from

different agencies had differing levels of hazardous materials training. Some had

participated in 24-hour courses, while others had received 80 hours of training. 

The management of the Henderson Fire Department indicated that they did not

send all their first response units for longer hazardous materials training because

they believed that the mutual aid agreement in the area would provide adequate

response from a fully-trained hazardous materials unit operated by Clark County. 

Fire fighters from Henderson were concerned that because of its location, there

would be a 30-minute travel time for the Clark County hazardous materials team. 

Although Clark County had primary responsibility for responding to hazardous

materials incidents in the industrial park, Henderson fire fighters were responsible

to civilians living immediately adjacent to the complex. Thus, an incident such as

this one, with exposures outside the industrial park, would involve the Henderson

fire fighters. Perhaps in recognition of this, Henderson Fire Department

management mentioned their plans to send several fire captains for additional

hazardous materials training. Fire fighters also cited delays in the response of the

hazardous materials teams, deployment of proper protective suits, and the setting

up of weather stations.

Some fire fighters felt that they were deployed into areas for which they were not

equipped with appropriate personal protective equipment. Those voicing this

concern expressed their belief that Kevlar® turnout gear was not recommended

for protection against chlorine gas. Fire fighters also expressed concern that the

SCBA units could not be relied upon to provide adequate protection without prior

fit testing, a procedure which was not routine in all departments visited. Some

fire fighters reported that they could smell chlorine while wearing their

respirators. It was also reported (and noted in medical records) that SCBA units
Page 13 - Health Hazard Evaluation Report No. 91-0230

were not always available for off-duty fire fighters who were summoned to the

incident. SCBA units and fully-encapsulated protective clothing should be worn

for chlorine spills and leaks with no fire.51 Structural fire fighter’s protective

clothing is considered not effective for exposure to chlorine, but it will provide

limited protection for short-term exposures.51 Full protective clothing, including

SCBA, rubber gloves, boots, and bands around legs, arms, and waist should be

provided so that no skin surface is exposed because chlorine gas can condense on

the skin and cause irritation and burns.52,53

Several fire fighters were concerned that appropriate decontamination procedures

were not always implemented. It was reported that fire fighters exposed to

chlorine were hosed down with water and that several sets of the turnout gear

were eventually decontaminated by commercial washing. According to the

Agency for Toxic Substances and Disease Registry (ATSDR), victims exposed

only to chlorine gas who have no skin or eye irritation do not need

decontamination.53 Victims who do experience skin or eye irritation should have

exposed skin and hair flushed with plain water for 2 to 3 minutes, washed twice

with mild soap, and then rinsed thoroughly with water.53 Exposed or irritated eyes

should be irrigated with plain water or saline for 15 minutes.53

To assist in the management, especially in the operation, coordination, and

effectiveness, of wide-scale fire suppression activities, a system was developed for

controlling personnel, facilities, equipment, and communications. This system is

known as the Incident Command System (ICS).54 A further refinement of the ICS

by fire service organizations addresses all types of emergency incidents, including

hazardous material situations, and includes performance criteria for the

components of a system that incorporates specific safety and health objectives. 

This has been developed into a nationally recognized standard known as the

Incident Management System (IMS).55 The NFPA has documented the

consequences of operating without an IMS, which may result in injuries and

deaths of fire fighters.55,56

The IMS establishes standard procedures to manage activities during emergency

situations. This system includes provisions for establishing an appropriate

command structure, such as single, unified, or lead agency. The IMS also dictates

that during complex incidents the incident commander should delegate authority

to a command staff consisting of safety, liaison, and information officers, and

establish the functional components of planning, logistics, operations,

communications, staging, and, if necessary, finance.
Page 14 - Health Hazard Evaluation Report No. 91-0230

During the response to the chlorine leak, both the HFD and CCFD implemented

the components of the IMS, including multi-agency coordination. Some of those

fire fighters interviewed expressed satisfaction at the way the IMS had been

successfully expanded to encompass the growing response to the incident. 

However, some of the descriptions that were reported suggest that organizational

problems remain. The investigators were told that there was not a common

communications frequency for all participating agencies. As a result, some

agencies were late in learning of developments in the situation. Several fire

fighters recounted their impression that activities at the command posts were often

disorganized. This may, in part, have resulted from the command post being

moved so frequently. Some fire fighters reported receiving orders to demobilize

without being given instructions for decontaminating their personal gear or

vehicles, while others were released without being given information about the

medical screening that had been established.

The representatives from the fire departments and the union felt that the overall

management of the incident was appropriate for the complex situations

encountered. However, the union representatives from the Henderson Fire

Department expressed their concern regarding the proximity of the HFD to the

BMI complex. Although the HFD is immediately adjacent to the BMI complex,

the complex is within the jurisdiction of the Clark County Fire Department which

is located several miles away in Las Vegas. The concern of the Henderson fire

fighters is that, due to the mutual aid response, the proximity of the HFD

predisposes them to be the first responders. Over the year prior to the chlorine

leak, the HFD had responded over 170 times to various calls at the BMI complex. 

The Henderson fire fighters felt they did not have adequate training to be first

responders to many hazardous situations, such as the present chlorine leak, that

require additional hazardous materials training and equipment. The union

representatives were also concerned with the number of fire fighters who

experienced symptoms, even though they were wearing SCBAs. Other concerns

included the use of turnout gear instead of other protective clothing, proper

decontamination procedures, and the effect of chlorine exposure on the integrity

of the turnout gear.

B. Health Effects

Five hospitals in the Henderson area were utilized to manage the triage of patients

from the incident scene. Medical records were reviewed for 18 patients whose

files were available at the Henderson City Offices. The majority of these noted

throat, eye, lung, sinus, and skin irritation, headaches, and nose bleeds. Many of
Page 15 - Health Hazard Evaluation Report No. 91-0230

the fire fighters complained of skin irritation and respiratory difficulty, even

though they put on SCBA's and protective clothing. 

Three pulmonary physicians, who saw the majority of patients on the day of the

incident and in follow-up appointments, were interviewed over the telephone. 

They reported that most of the patients had sore throats, headaches, coughing,

burning sensation in lungs and throat, frequent colds, aggravation of allergies, and

exacerbations of chronic obstructive pulmonary disease (COPD) following the

leak.

Confidential medical interviews were conducted with 10 Henderson fire fighters

who were involved in the incident response and available during the NIOSH

investigation. Eight reported experiencing burning irritation of the eyes, nose,

and/or throat, usually with coughing. Five of the ten reported shortness of breath

or chest tightness during the exposure; four were treated with bronchodilating

medications for up to 11⁄2 weeks after the incident. At the time of the interviews,

one fire fighter reported persistent throat irritation with a cough, but the other nine

said their symptoms had completely resolved. Two fire fighters said they had not

experienced any health effects during or after the exposure.

The initial response to the questionnaire was not satisfactory to the NIOSH

investigators; therefore, a second set of questionnaires was sent to representatives

of the two IAFF locals for distribution among all the fire fighters involved during

the incident. Still, NIOSH received a total of only 59 completed questionnaires. 

Because of this low response rate, the questionnaire data are of limited

epidemiologic use. Therefore, the following discussion is a descriptive account

based on information from the questionnaires, the interviews with exposed fire

fighters, the interviews with physicians who treated exposed workers, and the

review of available medical records. NIOSH received 42 completed

questionnaires from the 174 CCFD and HFD fire fighters involved in this

incident, and an additional 17 questionnaires from individuals other than fire

fighters. Since this investigation was requested by the IAFF, this account focuses

on the fire fighters, and only the information reported in the 42 questionnaires

completed by fire fighters is presented below.

Of the 42 respondents at the scene of the chlorine leak, most were stationed within

0.5 miles of the leak, with 16 being stationed near the actual leak site at some

point during the incident. Half the fire fighters reported being exposed to chlorine

gas for at least 3.0 hours. These estimated exposures ranged from 2 minutes to 14

hours. Forty-one respondents reported inhaling chlorine gas, although most used

some type of respirator during the exposure. A comparison of respirator use and
Page 16 - Health Hazard Evaluation Report No. 91-0230

distance from the chlorine leak indicated that fire fighters stationed nearer the

chlorine leak were more likely to have worn respirators.

Twenty-three respondents reported that they saw a physician following their

chlorine gas exposure, while ten reported being hospitalized. Seven of the fire

fighters who reported being hospitalized were stationed at the leak site, while the

remaining three were stationed elsewhere within a half mile of the leak. Nine of

the hospitalized fire fighters reported using a respirator during this incident.

Of the eight specific symptoms (coughing, chest tightness, wheezing, tearing eyes,

sore throat, headache, runny nose, and sneezing) included on the questionnaire,

cough, sore throat, chest tightness, and headache were the most frequently

reported symptoms. Other reported symptoms included phlegm production,

dizziness, feeling hoarse, shortness of breath, chlorine taste, bleeding from the

lungs, feeling lightheaded, nausea, sweating, frequent chest colds after exposure,

vomiting, fatigue, inflamed sinus, asthma/severe respiratory distress, severe chills,

and throat/nose irritation. A majority of the respondents experienced symptoms

associated with both the upper and lower respiratory systems. Nine of the fire

fighters who were hospitalized reported both upper and lower respiratory

symptoms. The remaining fire fighter who was hospitalized reported no

symptoms; no additional information was available as to why he was hospitalized.

All respondents stationed at the leak site reported respiratory symptoms of some

kind. In contrast, 4 of 24 participants who gave their location as at least 0.25

miles away from the leak site did not report any symptoms. Duration of the

symptoms also appeared to increase with proximity to the chorine leak. Three

respondents were still experiencing symptoms at the time they completed the

questionnaire, and all three were stationed at the leak site and had used a

respirator. One participant reported wheezing; another reported dizziness,

hoarseness, and being short of breath; and the third reported coughing, headache,

and tiring easily. Symptoms had resolved in the remaining 34 respondents. 

Although contrary to the protection provided by respirator use, the symptoms of

those fire fighters who did not wear respirators appeared to resolve more rapidly

than those who did wear respirators. This may indicate greater intensities of

exposure in locations where fire fighters wore respirators; non-use of respirators

because of the misperception of an environment as non-hazardous; and/or

improper use or fit of respirators.
Page 17 - Health Hazard Evaluation Report No. 91-0230

VII. CONCLUSIONS

Several fire fighters experienced adverse health effects from chlorine gas exposure,

including hospitalization and persistent respiratory symptoms. Many of the fire fighters

complained of skin irritation and respiratory difficulty, even though they used SCBA’s

and their structural fire fighter’s protective gear. The questionnaire data indicated that

the duration and severity of respiratory symptoms tended to increase with the proximity

to the leak site despite the use of respirators. However, the low response rate to the

questionnaire survey and potential selection biases limited the ability to further

generalize the questionnaire data. Possible explanations for the occurrence of

symptoms include delays in the donning or improper fit of respiratory protection and

the use of structural fire fighter’s protective gear instead of fully-encapsulated

protective clothing at the leak site. In addition, some limitations regarding the

application of incident command procedures were identified. These included the

CAER plan reportedly not being activated, delays in the response of the hazardous

materials teams, the confusion created by the unpredictability of the chlorine plume and

subsequent relocation of the command post on three occasions, and the lack of a

common communications frequency for all participating agencies.
Page 18 - Health Hazard Evaluation Report No. 91-0230

VIII. RECOMMENDATIONS

Based on the initial findings of this investigation, preliminary recommendations

regarding the chlorine leak response were made at the end of the site visit. The

following recommendations include the preliminary recommendations, as well as

recommendations based on further analysis of the available information, and previous

NIOSH investigations pertaining to fire fighter activities, and are offered to help

prevent future fire fighter injuries.

1. Since the Community Awareness and Emergency Response (CAER) plan for the

BMI complex was reportedly not activated during this incident, the HFD and

CCFD should review this CAER plan to ensure that it would be properly activated

and implemented for any future incident. The types of incidents that require the

activation of the CAER plan and appropriate implementation timetables should by

clearly defined to ensure the proper activation and implementation of the CAER

plan.

The CAER pre-planning for the BMI complex should be a joint effort between the

HFD and CCFD due to the HFD's proximity to the site and the likelihood of future

mutual aide responses. Both the HFD and CCFD should review their current

hazard communication programs to ensure that emergency response pre-planning

has been conducted for all sites within their jurisdictions where such pre-planning

is warranted. These sites would include all businesses and properties where there

are hazardous materials. The emergency response plans should be developed by

each site's responsible party and reviewed by the fire department. In addition, the

HFD and CCFD should investigate the existence of emergency response plans for

sites outside their jurisdiction where there is a probability of receiving a request for

mutual aide. These efforts should be coordinated with the fire departments of

neighboring communities which have mutual aide agreements.

2. Fire fighters, police, and paramedics often face serious exposures when responding

to incidents such as the chlorine leak because they lack appropriate protective

equipment. To prevent these emergency personnel from sustaining undue

exposures during these types of incidents, hazardous materials response teams

should be established. Because of the close proximity of the BMI complex to the

HFD and the distance involved for the response of the CCFD hazardous materials

team, the HFD should establish a hazardous materials response team. The basic

minimum elements for establishing such a response team are outlined in National

Fire Protection Association (NFPA) Standards 471 and 472.57,58
Page 19 - Health Hazard Evaluation Report No. 91-0230

3. The pre-planning process should address the feasibility of conducting training

programs and routine practice drills with hazardous materials team members and

other fire fighters. The feasibility of joint training programs and practice drills

with hazardous materials team members and other emergency response personnel

from all parties likely to be involved in any future incident at the BMI complex

should be investigated as part of the CAER plan.

4. The establishment of a hazardous materials response team should not preclude

appropriate training and equipment for other fire fighting units to handle chemical

incidents. Often these other units arrive on-scene at such incidents before the

hazardous materials response team and may perform support activities in the event

of a large incident.

5. Comprehensive reviews of the HFD and CCFD respiratory protection programs

and standard operating procedures should be conducted to ensure that fire fighters

are properly using their SCBAs, that they are equipped with respirators that have

been fit-tested, and that they have been receiving effective training.

6. Because fire fighters (as well as other emergency and rescue personnel) are

exposed to many hazardous materials during routine fire fighting and hazardous

materials incidents, a program of routine medical surveillance should be

established. An example of such a program is outlined in NFPA 1582.59

Additional monitoring may be appropriate for fire fighters who are members of a

hazardous materials team.

7. According to a representative of Du Pont, the manufacturer of Kevlar®, chlorine

gas could theorectically have some affect on this material.60 However, a relatively

short-term, one time exposure to chlorine gas should not significantly affect the

overall integrity of the Kevlar® turnout gear over the normal life of the garment. 

Both hydrochloric acid and hypochlorous acid (present in chlorine bleach) do

affect the integrity of Kevlar® and can be formed when chlorine reacts with water. 

Theoretically, these acids could have been formed if residual chlorine was present

when the turnout gear was hosed down with water or if the chlorine was able to

penetrate the garment and react with water retained in the Kevlar® fibers. 

However, the number of chlorine ions available to form these acids would likely be

insufficient to damage the the overall integrity of the turnout gear. The

manufacturers of Kevlar® and the fire fighter’s turnout gear should be contacted to

further investigate the effect of chlorine and other chemical exposures on suit

integrity. The existence of appropriate decontamination or cleaning procedures for

various chemical exposures should also be investigated by the fire departments.
Page 20 - Health Hazard Evaluation Report No. 91-0230

IX. REFERENCES

1. Karter MJ, LeBlanc PR [1994]. U.S. fire fighter injuries in 1993. NFPA

Journal, November/December. Quincy, MA: National Fire Protection

Association, pp. 57-66.

2. Toscano G, Windau J [1994]. The changing character of fatal work injuries. 

Monthly Labor Review, October. Washington, D.C.: Bureau of Labor Statistics,

pp. 19-20.

3. NSC [1993]. Accident Facts, 1993 Edition. Itasca, IL: National Safety Council,

pp. 51.

4. Treitman RD, Burgess WA, Gold A [1980]. Air contaminants encountered by

fire fighters. Am Ind Hyg Assoc J, 41:796-802.

5. Gold A, Burgess WA, Clougherty EV [1978]. Exposure of fire fighters to toxic

air contaminants. Am Ind Hyg Assoc J, 39:534-539.

6. Boettner EA, Ball G, Weiss B [1969]. Analysis of the volatile combustion

products of vinyl plastics. J Appl Polymer Sci, 13:377-395.

7. Montgomery RR, Reinhardt CF, Terrill JB [1975]. Combustion toxicology. J

Fire Flammability Combustion Tox, 2:179-185.

8. Hartzell GE, Packham SC, Switzer WG [1983]. Toxic products from fires. Am

Ind Hyg Assoc J, 44:248-255.

9. Committee on Fire Toxicology [1986]. Fire and smoke: understanding the

hazards. Washington: National Academy Press.

10. Mastromatteo E [1959]. Mortality in city firemen, II: a study of mortality in

firemen of a city fire department. AM A Arch Ind Health, 20:227-233.

11. Barnard RJ, Gardner GW, Diaco NV, et al. [1975]. Near-maximal ECG stress

testing and coronary artery disease risk factor analysis in Los Angeles city fire

fighters. J Occup Med, 17:693-695.

12. Bates JT [1987]. Coronary artery disease deaths in the Toronto fire department. 

J Occup Med, 29:132-135.
Page 21 - Health Hazard Evaluation Report No. 91-0230

13. Unger KM, Snow RM, Mestas J, et al. [1980]. Smoke inhalation in firemen. 

Thorax, 35:838-842.

14. Peabody H [1977]. Pulmonary function and the fire fighters. J Combustion Tox,

4:8-15.

15. Peters J, Theriault G, Fine L, et al. [1974]. Chronic effect of fire fighting on

pulmonary function. N Engl J Med, 291:1320-1322.

16. Sparrow D, Bosse R, Rosner B, et al. [1982]. The effect of occupational

exposure on pulmonary function: a longitudinal evaluation of fire fighters and

non-fighters. Am Rev Respir Dis, 125:319-322.

17. Douglas DB, Douglas RB, Oakes D, et al. [1985]. Pulmonary function of

London firemen. Br J Ind Med, 42:55-58.

18. Sidor R, Peters JM [1974]. Prevalence rates of chronic non-specific respiratory

disease in fire fighters. Am Rev Respir Dis, 109:255-261.

19. NIOSH [1976]. Occupational mortality in Washington State 1950-71. Vol. III. 

Cincinnati, OH: U.S. Department of Health, Education, and Welfare, Public

Health Service, Centers for Disease Control, National Institute for Occupational

Safety and Health, DHEW (NIOSH) Publication No. 76-175-C.

20. Enterline P, McKiever M [1963]. Differential mortality from lung cancer by

occupation. J Occup Med, 5:283-290.

21. NIOSH [1980]. Occupational mortality in the State of California 1959-1961. 

Cincinnati, OH: U.S. Department of Health and Human Services, Public Health

Service, Centers for Disease Control, National Institute for Occupational Safety

and Health, DHHS (NIOSH) Publication No. 80-104.

22. Feuer E, Rosenman K [1986]. Mortality in police and fire fighters in

New Jersey. Am J Ind Med, 9:517-527.

23. Lewis SS, Bierman HR, Faith MR [1983]. Cancer mortality among Los Angeles

City fire fighters: report to the Los Angeles fire department. Beverly Hills, CA: 

Institute for Cancer and Blood Research.
Page 22 - Health Hazard Evaluation Report No. 91-0230

24. NIOSH [1983]. Hazard evaluation and technical assistance report: Chester Fire

Department, Chester, PA. Cincinnati, OH: U.S. Department of Health and

Human Services, Public Health Service, Centers for Disease Control, National

Institute for Occupational Safety and Health, NIOSH Report No. HETA 83-360-

1495.

25. Abrams JL [1974]. Occupational mortality among professional fire fighters

[Dissertation]. Oklahoma City, OK: University of Oklahoma.

26. Demers PA, Heyer NJ, Rosenstock L [1992]. Mortality among fire fighters from

three Northwestern United States cities. Br J Ind Med, 49:664-670.

27. NIOSH [1992]. NIOSH recommendations for occupational safety and health. 

Compendium of policy documents and statements. Cincinnati, OH: U.S.

Department of Health and Human Services, Public Health Service, Centers for

Disease Control, National Institute for Occupational Safety and Health, DHHS

(NIOSH) Publication No. 92-100.

28. ACGIH [1994]. Threshold limit values and biological exposure indices for

1994-95. Cincinnati, OH: American Conference of Governmental Industrial

Hygienists.

29. Code of Federal Regulations [1992]. OSHA Table Z-2. 29 CFR 1910.1000. 

Washington, D.C.: U.S. Government Printing Office, Federal Register.

30. NIOSH [1994]. Pocket guide to chemical hazards. Cincinnati, OH: U.S.

Department of Health and Human Services, Public Health Service, Centers for

Disease Control, National Institute for Occupational Safety and Health, DHHS

(NIOSH) Publication No. 90-117.
Page 23 - Health Hazard Evaluation Report No. 91-0230

31. NIOSH [1977]. Occupational diseases: a guide to their recognition. Cincinnati,

OH: U.S. Department of Health, Education, and Welfare, Public Health Service,

Centers for Disease Control, National Institute for Occupational Safety and

Health, DHEW (NIOSH) Publication No. 77-181.

32. Hathaway GJ, Proctor NH, Hughes JP, Fischman ML [1991] Chemical hazards

of the workplace. 3rd ed. New York, NY: Van Nostrand Reinhold, pp. 152-154.

33. NIOSH [1988]. Occupational safety and health guidelines for chemical hazards. 

Cincinnati, OH: U.S. Department of Health and Human Services, Public Health

Service, Centers for Disease Control, National Institute for Occupational Safety

and Health, DHHS (NIOSH) Publication No. 88-118, Supplement I-OHG.

34. National Academy of Sciences [1976]. Committee on medical and biological

effects of environmental pollutants. National Research Council: Chlorine and

hydrogen chloride. Washington, D.C.: National Academy of Sciences, pp. 116-

123.

35. ACGIH [1986]. Documentation of the threshold limit values and biological

exposure indices. 5th ed. Cincinnati, OH: American Conference of

Governmental Industrial Hygienists, with supplements through 1990, pp.117.1-

3(87).

36. NIOSH [1976]. NIOSH criteria for a recommended standard: occupational

exposure to chlorine. Cincinnati, OH: U.S. Department of Health, Education,

and Welfare, Public Health Service, Centers for Disease Control, National

Institute for Occupational Safety and Health, DHEW (NIOSH) Publication No.

76-174.

37. Stewart CE, Sullivan JB [1992]. Military munitions and antipersonnel agents. 

In: Sullivan JB and Krieger GR, eds. Hazardous materials toxicology. 

Baltimore, Maryland: Williams and Wilkins, pp. 986-1014.

38. Frank R [1986]. Acute and Chronic respiratory effects of exposure to inhaled

toxic agents. Occupational Respiratory Diseases. DHHS Publication No. 86-

102, pp. 571-625.

39. Boulet LP [1988]. Increases in airways responsiveness following acute chlorine

exposure to respiratory irritants. Chest, 94:476-481.
Page 24 - Health Hazard Evaluation Report No. 91-0230

40. Wood BR, Colombo JL, Benson BE [1987]. Chlorine inhalation toxicity from

vapours generated by swimming pool chlorination tablets. Pediatrics, 79:427-

430.

41. Clayton GD, Clayton FE [1981]. Patty's industrial hygiene and toxicology,

Volume 2B, Toxicology. 3rd ed. New York, NY: John Wiley and Sons, pp.

2957-2964.

42. Gilchrist HL, Matz PB [1933]. Med Bull Vet Admin, 9:229.

43. Kaufman J, Burkons D [1971]. Clinical, roentgenological and physiological

effects of acute chlorine exposure. Arch Environ Health, 23:29-34.

44. Kowitz TA, et al. [1967]. Arch Environ Health, 14:545.

45. Brooks SM, Weiss MA, Bernstein IL [1985]. Reactive airways dysfunction

syndrome (RADS): persistent asthma syndrome after high level irritant

exposures. Chest, 88:376-384.

46. Walter EH, Parrish RW, Bevan C, Smith AP [1981]. Induction of bronchial

hypersensitivity: evidence for a role for protaglandins. Thorax, 36: 571-574.

47. Creese BR, Bach MK [1983]. Hyperreactivity of airways smooth muscle

produced in vitro by leukotrienes. Prostaglandins Leukotriens Med, 11:161-9

48. Freitag [1941]. Danger of chlorine gas. Z. Gesamte Schiess Sprengetoffwes.

49. ILO [1971]. Chlorine and compounds. In: Encyclopaedia of occupational health

and safety. 2nd ed. Vol. I (A-K). Geneva, Switzerland: International Labour

Office, pp. 287-288.

50. NPIRI [1983]. Raw materials data handbook, physical and chemical properties,

fire hazard and health hazard data. Vol. II. 2nd ed. Organic solvents. 

Bethlehem, PA: National Printing Ink Research Institute, pp. 831-857.

51. DOT [1993]. Emergency response guidebook 1993. Washington, D.C.: 

Department of Transportation, DOT P 5800.6.

52. NFPA [1986]. Fire protection guide on hazardous materials. 9th ed. Boston,

MA: National Fire Protection Association.
Page 25 - Health Hazard Evaluation Report No. 91-0230

53. ATSDR [1994]. Managing hazardous materials incidents. Medical management

guidelines for acute chemical exposures. Vol. III. Atlanta, GA: U.S.

Department of Health and Human Services, Public Health Service, Agency for

Toxic Substances and Disease Registry. 

54. NFA [1987]. The incident command system. Emmitsburg, MD: National Fire

Administration, NFA-ICS-SM.

55. NFPA [1990]. Standard on fire department incident management system. 

Quincy, MA: National Fire Protection Association, NFPA 1561-1990.

56. NFPA [1987]. Standard on fire department occupational safety and health. 

Quincy, MA: National Fire Protection Association, NFPA 1500-1987.

57. NFPA [1992]. Recommended practice for responding to hazardous materials

incidents. Quincy, MA: National Fire Protection Association, NFPA 471-1992.

58. NFPA [1992]. Standard for professional competence of responders to hazardous

materials incidents. Quincy, MA: National Fire Protection Association, NFPA

472-1992.

59. NFPA [1992]. Standard on medical requirements for fire fighters. Quincy, MA: 

National Fire Protection Association, NFPA 1582-1992.

60. Shaffer D [1995]. Telephone conversation on November 13, 1995, between D.

Shaffer, Du Pont Company and G. Kinnes, National Institute for Occupational

Safety and Health, Centers for Disease Control and Prevention, Public Health

Service, U.S. Department of Health and Human Services.
Page 26 - Health Hazard Evaluation Report No. 91-0230

X. AUTHORSHIP AND ACKNOWLEDGMENTS

Report Written by: Gregory M. Kinnes, M.S., C.I.H.

Industrial Hygienist

Industrial Hygiene Section

Steven Short, D.O.

Medical Officer

Division of Respiratory Disease Studies

Scott Deitchman, M.D.

Medical Officer

Medical Section

Technical Assistance by: Kathy B. Fedan

Statistician

Division of Respiratory Disease Studies

Report Prepared by: Kate L. Marlow

Office Automation Assistant

Originating Office: Hazard Evaluations and Technical

 Assistance Branch

Division of Surveillance, Hazard

 Evaluations, and Field Studies
Page 27 - Health Hazard Evaluation Report No. 91-0230

XI. DISTRIBUTION AND AVAILABILITY OF REPORT

Copies of this report may be freely reproduced and are not copyrighted. Single copies

of this report will be available for a period of three years from the date of this report

from the NIOSH Publications Office, 4676 Columbia Parkway, Cincinnati, Ohio 

45226. To expedite your request, include a self-address mailing label along with your

written request. After this time, copies may be purchased from the National Technical

Information Service (NTIS), 5285 Port Royal Road, Springfield, Virginia 22161. 

Information regarding the NTIS stock number may be obtained from the NIOSH

Publications Office at the Cincinnati address.

Copies of this report have been sent to:

1. International Association of Fire Fighters,

 Department of Occupational Health and Safety

2. IAFF, Locals 1883 and 1908

3. City of Henderson Fire Department

4. Clark County Fire Department

5. City of Henderson, Nevada

6. Clark County Health District

7. Pioneer Chlor Alkali Company, Inc.

8. OSHA, Region IX

For the purpose of informing affected employees, copies of this report shall be

posted by the employer in a prominent place accessible to the employees for a

period of 30 calendar days.