What is landfill gas?

What is landfill gas? 

Gases are formed in a landfill when buried
wastes decompose (breakdown by 
bacteria) or volatize (change from a liquid 
or solid to a vapor). These bacterial and 
chemical processes create gases that are 
unlikely to pose any serious health 
hazards, but they may cause odors that 
some people find unpleasant.   

What do I smell? 

The most common type of landfill is the 
municipal solid waste facility, which 
accepts household and non-hazardous 
commercial and industrial waste. It 
typically contains 60% organic material,
such as food and paper. Because organic 
material tends to produce a great deal of
gas, municipal solid waste landfills have
the potential to produce odors. 
Sulfides and ammonia are the most 
common sources of odor in landfill gas. 
Sulfides produce a strong, rotten-egg 
smell that humans can detect even at very 
low concentrations. Ammonia produces a 
pungent odor that many people are 
familiar with because it is often used in 
household cleaning products. Both are 
normally present in the air, regardless of 
the presence of a landfill. 
                              
                

Is landfill gas hazardous to 
my health?
  
Landfill gas may cause temporary 
discomfort, but it is not likely to cause 
permanent health effects. At extremely 
high concentrations, humans may 
experience eye irritation, headaches, 
nausea, and soreness of the nose and 
throat. People with respiratory ailments 
such as asthma are especially sensitive to 
these effects. However, these temporary 
conditions are reversed as soon as the 
gases are reduced or eliminated.  
There is another group of chemicals, 
called non-methane organic compounds 
(NMOCs), which may be present in the air 
near a landfill, though they are not likely to 
reach harmful levels. NMOCs may occur 
naturally, or be formed by chemical 
processes. There is concern that longterm exposure to high levels of NMOCs 
could lead to health problems, but health
studies have been largely inconclusive. 
Currently, there is not enough information 
about the impacts that lifestyle choices, 
such as tobacco use, may have on 
compounding the health effects from 
exposure to landfill gases. 
Many people find the odors emitted from a 
landfill to be unpleasant. Although these
odors are undesirable, no medical 
attention is usually required. Landfill odors 
may cause temporary symptoms such as
nausea and headache, but their effect on
the comfort of individuals is difficult to 
evaluate, because different individuals 
may react differently to the same type and 
intensity of odor. 


What other hazards are 
associated with landfill gas?
  
The migration of landfill gas creates health 
and safety concerns when the gas enters 
buildings and other confined areas. Under 
these circumstances, landfill gas may 
contribute to the following hazards: 
 EXPLOSION HAZARD
Gases may form an explosive mixture 
when combined with air in specific 
proportions. Methane (odorless), is the
only gas likely to be produced in high 
enough concentrations to pose any 
real explosion hazard. However, 
methane is only explosive when
diluted to concentrations between 5% 
and 15%. There also must be an 
ignition source for an explosion to 
occur. 

 ASPHYXIATION HAZARD 

Asphyxiation occurs if there is not 
enough oxygen in the air to breathe. If 
landfill gases collect in a confined 
space, they have the potential to 
create an oxygen-deficient 
environment. Carbon dioxide is the 
gas most likely to create an
asphyxiation hazard. Symptoms of 
asphyxiation include headache, 
increased breathing and heart rate, 
and dizziness. These symptoms are 
reversed when exposure is eliminated.