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High Throughput SiRNA Screening for Chloropicrin and Hydrogen Fluoride-Induced Cornea Epithelial Cell Injury

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Spacecraft Maximum Allowable Concentrations for Hydrogen Fluoride.

Chiu-Wing Lam, Valerie E Ryder

Aerospace Medicine and Human Performance

|October 16, 2022

Summary

This summary is machine-generated.

Spacecraft maximum allowable concentrations (SMACs) for hydrogen fluoride (HF) were established. Short-term exposure limits are set at 3 ppm to allow mild irritation, while long-term limits are 0.3 ppm to prevent health effects.

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Published on: March 29, 2016

Area of Science:

Aerospace Medicine
Occupational Health
Toxicology

Background:

Spacecraft maximum allowable concentrations (SMACs) guide chemical exposure limits for crew health and performance.
Hydrogen fluoride (HF) is an irritant gas that can be produced in spacecraft from material combustion or overheating.
HF primarily affects the upper respiratory tract upon inhalation.

Purpose of the Study:

To develop NASA's hydrogen fluoride (HF) SMACs for spacecraft environments.
To determine safe exposure limits for crew during nominal and emergency situations.
To mitigate potential crew health effects and performance degradation from HF exposure.

Main Methods:

Systematic review of toxicological data from electronic databases.
Inclusion of previous assessments and reviews of hydrogen fluoride (HF).
Analysis of human inhalation data from Lund (short-term) and Largent (subchronic) studies.

Main Results:

Human inhalation studies indicated very mild respiratory irritation at approximately 3 ppm of HF.
Short-term (1-h and 24-h) SMACs for HF were set at 3 ppm.
Subchronic and chronic (7-d to 1000-d) SMACs for HF were established at 0.3 ppm.

Conclusions:

The 3 ppm short-term SMAC aligns with criteria allowing mild, transient crew irritation.
The 0.3 ppm long-term SMAC is established to safeguard against cumulative health or performance impacts.
These HF SMACs provide crucial safety guidelines for space missions.