Bromotrifluoromethane

Exposure related observations in humans: other data

Administrative data

Endpoint:

exposure-related observations in humans: other data

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study well documented.

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Human performance and physiological function during a 24-hr exposure to 1% bromotrifluoromethane (Halon 1301)

Author:

D.S. Calkins et al.

Year:

1993

Bibliographic source:

Fundamental and applied toxicology 20, 240-247

Reference 2

Reference Type:

publication

Title:

Toxicokinetics of lnhaled Bromotrifluoromethane (Halon 1301) in Human Subjects

Author:

CHIU-WING LAM, FRANCIS W. WEIR, KATHRYN WILLIAMS-CAVENDER,MIGUEL N. TAN, THEODORE J. GALEN, AND DUANE L. PIERSON

Year:

1993

Bibliographic source:

FUNDAMENTAL AND APPLIED TOXICOLOGY 20, 231-239 (1993)

Materials and methods

Endpoint addressed:

other: other: Effects on human pulmonary, hepatic, hematologic, cardiovascular and central nervous system function

Principles of method if other than guideline:

The study was designed to assess changes in performance and physiological function of 10 adult males between two 24-hr chamber exposures, one to air containing 1% (10,000 ppm) Halon 1301 and another to air only.

Test material

Test material information

Test material form:

gas

Method

Ethical approval:

other: other: The study protocol was approved by the the Human Research Policy and Procedures Commitee of Johnson Space Center and the Boards for Human Research of Methodist Hospital, and The University of Texas Health Science Center at Houston.

Details on study design:

The study participants were randomly assigned to the test groups. Chamber exposures were separated by at least 7 days and conducted in a double-blind manner, which means neither the subjects nor the investigators (except for the chamber technicians, chamber conductor, and a physician) knew the content of the chamber atmosphere.

The subjects were paid civilian male volunteers, 25-40 years of age, within 10% of their desirable weight.
Prospective subjects were excluded if they had any clinically detectable infection; respiratory, cardiovascular, mental, or neurological problems; hypersensitivity
to foreign agents; dependence on alcohol, smoking, or drugs; phobias; or took interfering medications (e.g, tranquilizers or narcotics). Before each chamber exposure subjects' urine was screened to ensure that no drugs that could interfere with the study had been taken.

Performance assessment:
Cognitive and motor performance was assessed before, during, and after chamber exposures using seven scales of the Automated Portable Testing System (APTS; Essex Corp., Orlando,FL; see table 1 in section "any other information on materials and methods incl. tables"). The APTS was developed for studying the effects of environmental stress on skilled performance.
During the experiment each participant completed the eight-scale APTS battery on at least 32 occasions.

Assessment of physiological effects:
Physiological data were gathered before, during, and after each 24-hr chamber exposure from hematology (12 variables), serum chemistry (20 variables), urinalysis (2 variables), pulmonary function testing (14 variables) and vital signs measurements (4 variables); resulting in values for 52 physiological variables.
Blood and urine samples were obtained before the initial chamber exposure, after each chamber exposure, and again 24 hr after the participants left the chamber.
Parameters assessed:
Standard multichannel analyzer chemistry profile (SMA-20); complete blood cell count (including differential count and platelet count) and prothrombin and partial thromboplastin times; standard urinalysis; spirometry and full lung volume measurements; heart rates and rhythms (continously measured by EKG); blood pressure and temperature.

Exposure assessment:

not specified

Details on exposure:

The participants entered the chamber in pairs. Beginning each 24-hr exposure condition at about 1400 hr (2:00 PM) and terminating each exposure condition at about 1400 hr (2:00PM) the next day.

Results and discussion

Results:

Performance effects:
Data were obtained for only 7 participants, as one participant had an acute panic attack and therefore the data for that pair of participants was lost. For another participant, data for two testing occations could not be retrieved from the computer.

Results showed that performance was worse during Halon inhalation for 9 scales (out of 13). However, the magnitude of performance degradation was statistically significant for only two scales (Code substitution; numer of correct responses and response time).

Physiological effects:
Data were obtained from eight participants only, as one participant had an acute panic attack and therefore the data for that pair of participants was lost.
All values were within clinically acceptable limits. However, statistically significant differences in amounts of chande relative to baseline for the air and Halon 1301 conditions were found for the following variables:
blood urea nitrogen, uric acid, segmented neutrophils, lymphocytes, prothrombin time and FEV25-57 (force expired volume).
No statistically significant interaction effects were observed.

Applicant's summary and conclusion

Executive summary:

Four pairs of adult male subjects were each exposed in a double-blind fashion for 24 hr to 1% (10,000 ppm or 60,875 mg/m3) Halon 1301 and to air in two separate exposures approximately 1 week apart.

Cognitive and motor performance measurements were obtained before, during and after the exposure period. Exposure of 1% bromotrifluoromethane in air for 24 hours led to a reduction in performance in two out of 13 scales of the APTS Battery. Actual and estimated magnitudes of the decrements were no greater than 5% of baseline values.

Measurements of physiological condition were performed before, during and after the exposure period and consited of clinical chemistry analysis of blood and urine, pulmonary functin tests and monitoring of vital signs.

Significant changes during Halon inhalation were observed for 6 out of 52 variables assessed. However, all physiological values remained within clinically acceptable limits. Cardiovascular effects were not observed.

The authors concluded, that exposure to 1% Halon 1301 for 24 hours can lead to minor disturbances of the central nervous system as assessed by cognitive tasks.