Perhaps nothing is more alarming and disagreeable than the odors emitted from a cadaver. As a human body decomposes, different types of gases are expelled from the remains. The expulsion of a malodorous stench commences within a matter of a day following death, if a body is left unattended. The stench magnifies – and significantly so – over time. Decomposing human remains present what is known as a biohazard. This fact raises the question of whether odors from a dead body are classified as biohazards.

Most Prevalent Gases Released by Decomposing Human Remains

Before diving into the issue of decomposition odors and biohazards, you need to understand some basics about the gases involved. The most common gases that emit from decomposing human remains are:

  • Cadaverine
  • Putrescine
  • Skatole
  • Indole
  • Hydrogen sulfide
  • Methanethiol
  • Dimethyl disulfide
  • Dimethyl trisulfide

These various gases combine to form the overwhelming, nauseating stench associated with a decomposing cadaver. These various gases emit different odors that smell like:

  • Rotting fish
  • Feces
  • Mothballs
  • Rotten eggs
  • Rotten cabbage
  • Garlic

As these gases combine, the uniquely awful stench associated with death is created.

Two Particularly Dangerous Chemicals

Two potentially dangerous chemicals are created as a result of the decomposition process: Cadaverine and putrescine. In large quantities, these chemicals can be harmful to humans. The danger is found in the liquid forms of cadaverine and putrescine and not the gaseous incarnation.

Emphasis needs to be placed on the fact that these two types of liquid chemicals only present a risk of harm to humans when present in high quantities. A decomposing human cadaver is not capable of producing liquid cadaverine or putrescine in quantities sufficient to harm a person.

Biohazards and Gases from a Decomposing Human Cadaver

Although the stench emitted from a decomposing human body appropriately is described as unbearably unpleasant, the stench and the gases combining to cause it, are not classified as biohazards. In other words, dangerous pathogens are not present in the gases associated with the stench of decomposing remains. Thus, humans are not at risk of contracting a disease from exposure to the odor of a dead both.

Having clarified this important point, the stench itself can be so horrible that a person exposed to it can become nauseous. However, becoming nauseous is very different from becoming ill because an individual contracted a disease through some sort of pathogen like a virus or bacterium.

Other Decomposing Animals and Odors

A person not trained in the forensic sciences is not likely to be able to discern between the stench associated with a decomposing human body and that of other mammals. The reality is that different animals (including humans) emit a different array of gases when decomposing after death. Thus, there technically is a difference in the gases emitted, resulting in what really are different types of stenches. This fact is why cadaver dogs are able to discern between human remains and those of other animals. Some forensic experts can discern the difference as well. Moreover, a chemical analysis of the gas composition can ascertain what type of mammal has died.

How Would a Person Encounter a Decomposing Human Body?

In considering the biohazardous risks associated with a decomposing human body, a fair question is how and why would a person come into contacted with such a cadaver? The reality is that an “average person” is not highly likely to encounter the remains of a deceased person well into the decomposition process.

The most common type of situation in which a person encounters a decomposing body emitting gases is when a family member or friend has died what is classified as an unattended death. An unattended death is one in which a person dies alone and whose remains are not promptly discovered. In cases of an unattended death, days, weeks, or even months can pass before the remains are found.

Scene of Decomposing Remains is a Biohazard

Despite gases not being biohazards, the scene of a decomposing corpse does present a true biohazardous situation. Blood and other bodily fluids can contain dangerous pathogens, viruses and bacteria capable of causing serious diseases in humans that come into contact with these substances.

Because of these risks, decomposing body cleanup necessitates the use of biohazard-rated personal protective equipment that includes:

  • Protective eyewear
  • Gloves
  • Smock or uniform
  • HEPA mask or respirator

The health risks and the inconceivable stench underscore the advisability to retain the services of a decomposing body cleanup professional, or an unattended death cleanup company, to address the remediation of this type of situation. In addition, it’s never advisable for a person to embark on cleaning up after the unattended death of a loved one. Losing a person in such a manner – or in a homicide or suicide – is truly traumatic enough. A person’s emotional state and grieving process doesn’t need to be further aggravated by trying to undertake decomposing body or unattended death cleanup on his or her own.


Emily Kil

Co-Owner of Eco Bear Biohazard Cleaning Company

Together with her husband, Emily Kil is co-owner of Eco Bear, a leading biohazard remediation company in Southern California. An experienced entrepreneur, Emily assisted in founding Eco Bear as a means of combining her business experience with her desire to provide assistance to people facing challenging circumstances. Emily regularly writes about her first-hand experiences providing services like biohazard cleanup, suicide cleanup, crime scene cleanup, unattended death cleanup, and other types of difficult remediations in homes and businesses.