Skip to Main Content

CHAPTER 2-76: GASES, IRRITANT

John R. Balmes

INTRODUCTION

A vast number of compounds produce irritant effects when inhaled in the gaseous form. The most common source of exposure to irritant gases is industry, but significant exposures may occur in a variety of circumstances, such as after mixing cleaning agents at home, with smoke inhalation in structural fires, or after highway tanker spills.

MECHANISM OF TOXICITY

Irritant gases often are divided into two major groups on the basis of their water solubility (Table II–31).

  1. Highly soluble gases (eg, ammonia and chlorine) are readily adsorbed by the upper respiratory tract and rapidly produce their primary effects on moist mucous membranes in the eyes, nose, and throat.

  2. Less soluble gases (eg, phosgene and nitrogen dioxide) are not rapidly adsorbed by the upper respiratory tract and can be inhaled deeply into the lower respiratory tract to produce delayed-onset pulmonary toxicity.

TOXIC DOSE

The toxic dose varies with the properties of the gas. Table II–31 illustrates the workplace exposure limits (TLV-TWA) and the levels immediately dangerous to life or health (IDLH) for several common irritant gases.

TABLE II–31.IRRITANT TOXIC GASES
View Table||Download (.pdf)
TABLE II–31. IRRITANT TOXIC GASES
Gas TLVa (ppm) IDLHb (ppm)
High water solubility    
 Ammonia 25 300
 Chloraminec N/A N/A
 Formaldehyde 0.3(C) 20
 Hydrogen chloride 2(C) 50
 Hydrogen fluoride 2(C) 30
 Nitric acid 2 25
 Sulfur dioxide 0.25(S) 100
Moderate water solubility    
 Acrolein 0.1(C) 2
 Chlorine 0.5 10
 Fluorine 1 25
Low water solubility    
 Nitric oxide 25 100
 Nitrogen dioxide 3 20
 Ozone 0.2d 5
 Phosgene 0.1 2

aThreshold limit value, ACGIH-recommended exposure limit as an 8-hour time-weighted average for a 40-hour workweek (TLV-TWA). "(C)" indicates ceiling limit, which should not be exceeded at any time (TLV-C). "(S)" indicates short-term exposure limit.

bAir level considered immediately dangerous to life or health (idLH), defined as the maximum air concentration from which one could reasonably escape within 30 minutes without any escape-impairing symptoms or any irreversible health effects.

cChloramine is formed when chlorine or hypochlorite is added to water containing ammonia. It is usually a mixture of mono-, di-, and trichloramines. (N/A: TLV and idLH are not established.)

dFor exposure of no more than 2 hours (all workloads).

CLINICAL PRESENTATION

All these gases may produce irritant effects in the upper and/or lower respiratory tract, but warning properties and the onset and location of primary symptoms depend largely on the water solubility of the gas and the concentration of exposure.

  1. Highly soluble gases. Because of the good warning properties (upper respiratory tract irritation) of highly soluble gases, voluntary prolonged exposure to even low concentrations is unlikely.

    1. Low-level exposure causes rapid onset of mucous membrane and upper respiratory tract irritation; ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.

This site uses cookies to provide, maintain and improve your experience. MH Privacy Center Close