Health : General Health Advice  

Inhalation of Toxic Chemicals

What is Hazardous Chemical Inhalation Exposure?
Hazardous chemicals generally take the form of either gases or liquids, depending on how they are stored. In many regions of the world, chemicals are transported by rail or vehicle in compressed tanks, following strict guidelines as set forth by international chemical regulations and recommendations. However, despite manufacturers' attempts to follow these regulations, unforeseen circumstances such as weather, road or rail conditions, sabotage, or other accidents can cause an unintentional release and emit harmful vapors or fumes that can cause damage to human health. Some chemicals stored as solids are much less volatile in nature, and present less of an inhalational hazard. The WHO reports that between 2000 and 2009, there were 3,200 technological disasters with close to 1.5 million people affected.

How Does Inhalation Exposure Occur?
Hazardous inhalation exposure can occur when a material deemed hazardous to human health is released through a leak or rupture in the containment vessel causing a "plume," cloud, or stream into the surrounding air. This can be highly localized or dispersed over a wider arena depending on:

  • Size of the release
  • Atmospheric conditions
  • Interaction with other chemicals
  • Timeliness of response

Many chemicals have distinctive odors, tastes, and colors; however, there are many discrete chemicals and compounds that do not have these properties and can be harmful to human health if inhaled. Some chemicals, such as ammonia, chlorine, or bromine are directly released, and some are by-products of other chemical reactions, such as carbon monoxide. Generally, industrial chemicals that are directly released will have some type of odor or color associated with them.


The safest way to prevent inhalational exposure in the event of an accidental release is through:

  • Avoiding the offending agent, which will largely depend on your location in relation to the accident, your ability to safely and efficiently evacuate the area in question, and the conditions surrounding the release.
  • For short-term releases (less than 4 hours of expected exposure time) shelter-in-place
  • Preventing toxic fumes entering into your living space
  • Turn off external ventilation systems
  • Seal windows
  • Take shelter if outdoors
  • Cover mouth and nose with cloth
  • Protect eyes as much as possible while maintaining visibility
  • Phone for emergency assistance and poison control if exposure has occurred
  • When evacuation is an option, move to an area upwind and higher ground than the area of incident

Know that environmental conditions can change, and be prepared for additional movement if necessary. This is especially true of a chlorine gas incident.

Chlorine accounts for more than 50 percent of all chemical processes in the world outside of the fuel and metals industries.

A significant respiratory irritant, it is heavier than air and will settle when vaporized. Behavior of the release is dependent on weather conditions, terrain features, and how the release occurred, among other factors.

Other chemicals may behave differently in the environment. However, the most important factor during an accidental chemical release is to remain as calm as possible.

Increased respiratory demand secondary to panic will increase potential exposure to the offending agent by an increased respiratory rate.

Respirators carry with them physical and psychological demands, many that may be unforeseen by the user until the device is actually in place. A crisis is not the time to find that added demands of a respirator place an undue burden on an employee and their fellow colleagues. Many countries require that respirators are fit to individuals, a medical exam has been performed to ensure fitness, and adequate training has been provided.


If you can smell or taste a "chemical," there is a chance you may be able to partially identify the agent and report it to authorities, poison control, and/or a medical provider for specific advice.

Each chemical and compound will have an MSDS Sheet (Material Safety Data Sheet) regarding the safe handling and health procedures specific to that chemical.

For initial respiratory exposures, getting to fresh air and oxygen to protect the airway for breathing is of primary importance.

Coughing, runny nose, and tearing are common body defenses to offending agents.

Exposures may exacerbate underlying medical conditions, particularly pulmonary or renal conditions.

For any inhalation exposure, have a medical provider determine if additional testing or treatment is necessary.

Delayed onset of symptoms are not unusual.

Some treatment options are not always advisable for all chemicals.

A preliminary exam may include a physical assessment, bloodwork, a chest X-ray, and urine sample, depending on the extent and nature of the release.


  • Acute symptoms are treated first
  • Prevention of infection would be addressed as a secondary measure
  • Treatment will be highly individualized depending on chemical and any underlying conditions
  • Initial cardio-vascular and respiratory stabilization would be addressed first

If evacuation with adequate sheltering is possible, minimal exposure is likely, and short- as well as long-term consequences should also be minimal.

The WHO keeps a listing of International Poison Control Centers accessible at: href="

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