- Despite being the largest component of the air we breathe, nitrogen can be fatal in high concentrations.
- Nitrogen asphyxiation remains a significant occupational hazard, particularly in confined spaces.
- Multiple incidents of nitrogen-related deaths and injuries highlight the importance of effective safety measures.
- Recognizing and responding to the dangers of nitrogen involve training, warning systems, and robust rescue systems.
The Deceptive Nature of Nitrogen
Nitrogen, an invisible, tasteless, and odorless gas, makes up about 78 percent of the Earth’s atmosphere. Its omnipresence makes it easy to overlook, and we tend to take this inert gas for granted. However, under specific conditions, nitrogen can transform from an innocuous substance to a silent killer.
Two contractors working at Valero Energy Corp.’s Delaware City, Del., oil refinery became victims of nitrogen asphyxiation in 2005. The pair were assigned to re-attach piping to a vessel to bring it back online. Unbeknownst to them, they were working in an environment with a high concentration of nitrogen and less than 1 percent oxygen, leading to their rapid unconsciousness and, ultimately, their death.
This tragedy highlights the potential risk posed by nitrogen, particularly in confined spaces and industries where the gas is commonly used.
A Pattern of Nitrogen-Related Incidents
An analysis of workplace deaths and injuries caused by nitrogen asphyxiation between 1992 and 2002 conducted by the Chemical Safety and Hazard Investigation Board (CSB) revealed 85 such incidents. These incidents resulted in 80 fatalities and 50 injuries, underscoring the seriousness of nitrogen-related risks.
Among these, 67 incidents involved workers in or near confined spaces, highlighting these areas as particularly vulnerable to nitrogen-related hazards. Failure to detect oxygen-deficient atmospheres was a major contributor to these incidents. Approximately 10 percent of fatalities occurred during attempted rescues of fallen colleagues. Cases of mix-up between nitrogen and breathing air also contributed to the overall incidents.
The Importance of Warning Systems
Regulatory standards, like those set by the Occupational Safety and Health Administration (OSHA), require the identification of all confined spaces in the workplace and their classification as permit-required if they present hazards. Such spaces should have clear warning signs posted. The CSB goes a step further, suggesting the implementation of flashing lights, audible alarms, and auto-locking entryways to prevent unauthorized access.
The Need for Continuous Atmospheric Monitoring
Regular and systematic testing of the atmosphere within confined spaces is critical to ensure safety. Before workers enter a confined space, the atmosphere should be tested and confirmed safe. Continuous monitoring while workers are in the space is equally vital.
Ensuring Ventilation with Fresh Air
For workers entering a confined space without wearing a supplied-air breathing apparatus, providing continuous ventilation with forced-draft fresh air is crucial. Fresh-air ventilation is particularly applicable when an area has recently been purged with nitrogen or some other gas, and the area has been brought to a minimum safe breathing level of 19 1/2 percent oxygen.
The Crucial Role of a Rescue System
Human instinct often leads us to attempt rescue when we see someone in trouble. However, in an environment where nitrogen asphyxiation is a risk, this instinct can prove deadly. Comprehensive training in recognizing the dangers of nitrogen-enriched environments and proper rescue procedures can help prevent tragic outcomes.
The Integrity of Breathing Air
In situations where the oxygen concentration is low, workers must be supplied with breathing air through a self-contained breathing apparatus or an airline respirator. It is essential to ensure an uninterrupted flow of air and an alternate power source for the air compressors.
Preventing Mix-Ups between Nitrogen and Breathing Air
Distinguishing between nitrogen and breathing air is crucial to avoid dangerous mix-ups. Clear labels and incompatible fittings can prevent the accidental cross-connection of these gases.
The Power of Training
A well-informed workforce is the best defense against nitrogen-related hazards. Training must include the use of ventilation systems, retrieval systems, and atmospheric monitoring systems. Workers should also be trained in hazard communication and safety practices for entry into confined spaces.
The Bottom Line
While nitrogen forms a significant part of the air we breathe, it can pose a severe threat under certain conditions. Recognition of these dangers, coupled with effective training, warning systems, and rescue systems, can help prevent nitrogen-related incidents. Awareness and vigilance are key to managing the silent yet potent risk of nitrogen.