September PPE Focus: 4-Gas Monitors

Personal Protective Equipment Focus: 4-Gas Monitors

On one January day that seemed perfectly ordinary, tragedy devastated three families who watched a loved one leave for work that morning and never return. Four workers responded to complaints of sewage backup in a residential area. When they arrived on site, one person removed a manhole cover and descended into the sewer. Not hearing anything from the first entrant, the second worker descended into the manhole. Shortly thereafter, the third worker became concerned for the safety of his co-workers and descended into the manhole. After emergency services arrived on the scene, one rescue worker entered the space without an air tank, desperate to rescue the trapped workers; the gases rendered the rescue worker unconscious in seconds. All three workers died, asphyxiated by the toxic gases.

The rescue worker was flown to the hospital in critical condition; he spent the next week in a medically induced coma. Months later, he was medically cleared to return to work. Other emergency respondents were also treated for their exposure to the hazardous atmosphere within the manhole.

Investigations revealed that rotting vegetation created a dangerous buildup of hydrogen sulfide and methane that displaced the breathable air in the space, asphyxiating the three workers and critically injuring the unprepared rescue worker.

The Dangers of Hazardous Atmospheres

Hazardous atmospheres are a significant hazard when working in confined spaces and when excavating. In underground and sewer work, and in some industrial processes, organic matter that decomposes creates dangerous levels of methane and hydrogen sulfide. These gases displace the breathable atmosphere, forcing oxygen and nitrogen that we need to breathe away as they fill the space. In large concentrations, these gases cause people to lose consciousness and asphyxiate in the oxygen-deprived atmosphere.

In addition to displacing the atmosphere, they also create an explosive potential. One small spark can ignite the gases and generate an explosion. Some processes create excess oxygen, creating a similarly explosive and dangerous situation.

The Need for 4-Gas Monitors

Gas monitors are the essential tool that alerts employees to hazardous atmospheres before they become exposed. The most common version is a 4-gas monitor that analyzes the atmosphere and detects four common hazards: hydrogen sulfide, oxygen levels, carbon monoxide, and the lower explosive limits of a variety of combustible gases, such as methane. Employees who are trained to properly monitor the atmosphere in confined spaces, excavations, or other spaces with potentially hazardous atmospheres, can identify the hazardous atmospheres before another employee can be exposed to them. Specialized monitors are available to test for more specific hazardous atmospheres, which is particularly beneficial in manufacturing and industrial applications whose processes use or create other hazardous gases.

A 4-gas monitor could have alerted the workers to the hazardous atmosphere in the manhole before they entered it, preventing the tragedy that cost them their lives, and robbed their families of their husbands, fathers, and sons. Don’t let a similar tragedy devastate your employees and their families. Provide them with the tools and training that they need so that their families never have to find out that their loved one is never coming home from work again.