Sterilant gas monitoring is the detection of hazardous gases used by

health care Health care, or healthcare, is the improvement or maintenance of health via the preventive healthcare, prevention, diagnosis, therapy, treatment, wikt:amelioration, amelioration or cure of disease, illness, injury, and other disability, physic ...

and other facilities to sterilize medical supplies that cannot be sterilized by heat or steam methods. The current

FDA The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...

approved sterilant gases are

ethylene oxide Ethylene oxide is an organic compound with the chemical formula, formula . It is a cyclic ether and the simplest epoxide: a three-membered ring (chemistry), ring consisting of one oxygen atom and two carbon atoms. Ethylene oxide is a colorless ...

hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscosity, viscous than Properties of water, water. It is used as an oxidizer, bleaching agent, and antiseptic, usua ...

and

ozone Ozone () (or trioxygen) is an Inorganic compound, inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , break ...

. Other liquid sterilants, such as

peracetic acid Peracetic acid (also known as peroxyacetic acid, or Percidine) is an organic compound with the formula CH3CO3H. This peroxy acid is a colorless liquid with a characteristic acrid odor reminiscent of acetic acid. It can be highly corrosive. Perac ...

, may also be used for sterilization and may raise similar

occupational health Occupational safety and health (OSH) or occupational health and safety (OHS) is a multidisciplinary field concerned with the safety, health, and welfare of people at work (i.e., while performing duties required by one's occupation). OSH is re ...

issues.

Sterilization Sterilization may refer to: * Sterilization (microbiology), killing or inactivation of micro-organisms * Soil steam sterilization, a farming technique that sterilizes soil with steam in open fields or greenhouses * Sterilization (medicine) render ...

means the complete destruction of all biological life (including

viruses A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almo ...

and sporoidal forms of

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

), and sterilization efficacy is typically considered adequate if less than one in a million

microbe A microorganism, or microbe, is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells. The possible existence of unseen microbial life was suspected from antiquity, with an early attestation in ...

s remain viable.

Hazards of sterilant gases

Since sterilant gases are selected to destroy a wide range of biological life forms, any gas which is suitable for sterilization will present a hazard to personnel exposed to it.

NIOSH The National Institute for Occupational Safety and Health (NIOSH, ) is the United States federal agency responsible for conducting research and making recommendations for the prevention of work-related injury, illness, disability, and death. It ...

's IDLH (immediately dangerous to life and health) values for the three sterilant gases are 800 ppm (ethylene oxide), 75 ppm (hydrogen peroxide) and 5 ppm (ozone). For comparison, the IDLH of cyanide gas (

hydrogen cyanide Hydrogen cyanide (formerly known as prussic acid) is a chemical compound with the chemical formula, formula HCN and structural formula . It is a highly toxic and flammable liquid that boiling, boils slightly above room temperature, at . HCN is ...

) is 50 ppm. The

OSHA The Occupational Safety and Health Administration (OSHA; ) is a regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces. The United States Congress established ...

PEL (

permissible exposure limit The permissible exposure limit (PEL or OSHA PEL) is a legal limit in the United States for exposure of an employee to a chemical substance or physical agents such as high level noise. Permissible exposure limits were established by the Occupational ...

) will be considerably lower than this; 1 ppm for ethylene oxide, or 5 ppm for a 15 minute

short-term exposure limit A short-term exposure limit (STEL) is the acceptable average exposure over a short period of time, usually 15 minutes as long as the time-weighted average is not exceeded. STEL is a term used in exposure assessment, occupational health, industrial ...

. Thus exposure to even low levels of sterilant gas should not be treated casually and most facilities go to great lengths to adequately protect their employees. In addition to toxicity, ethylene oxide is flammable (from above 3%) and ozone is damaging to equipment not designed to resist it. Sterilizer manufacturers go to great lengths to make their products as safe as possible but, as with any mechanical device, they can and sometimes do fail and leaks have been reported. The odor threshold for these gases is above the PELs and for ethylene oxide it is 500 ppm, approaching that of the IDLH. Odor is thus inadequate as a monitoring technique. Continuous gas monitors are used as part of an overall safety program to provide a prompt alert to nearby workers in the event that there is a leak of the sterilant gas.

Monitoring equipment

The monitor alarms are typically set to warn if the concentrations exceed the

permissible exposure limits (PELs), 1.0 ppm for ethylene oxide29 CFR 1910.1047
/ref> and 1.0 and 0.1 ppm for hydrogen peroxide and ozone respectively.29 CFR 1910.1000, App. Z-1
/ref> The PELs are calculated as 8 hour time weighted average values (i.e. the average exposure over a typical shift).

References

{{Reflist, refs= {{Cite web , title=The Myths of Sterilant Gas Safety Exposed , date=16 April 2008 , website=Infection Control Today , url=http://www.infectioncontroltoday.com/articles/2008/04/the-myths-of-sterilant-gas-safety-exposed.aspx {{Cite web , title=Sterilant Gas Mixtures , publisher=SCI Analytical , url=http://scicalgas.com/specialty-gas/medical-gas/sterilant-gas/ {{cite web , url=http://www.atsdr.cdc.gov/mmg/mmg.asp?id=730&tid=133 , archive-url=https://web.archive.org/web/20100528070218/http://www.atsdr.cdc.gov/MMG/MMG.asp?id=730&tid=133 , url-status=dead , archive-date=May 28, 2010 , series=Medical Management Guidelines (MMGs) , title=Ethylene Oxide , publisher=

ATSDR The Agency for Toxic Substances and Disease Registry (ATSDR) is a federal public health agency within the U.S. Department of Health and Human Services (HHS). The agency focuses on minimizing human health risks associated with exposure to hazar ...

{{Cite web , title=Steri-Trac® Sterilant Gas Monitoring System , publisher= ChemDAQ , url=https://www.scicanmedical.ca/site/scican_medical/assets/pdf/chemdaq_steri-trac%EF%BF%BD_sterilant_gas_monitoring_system__en_.pdf {{Cite journal , title=The Essentials of Sterilant Gas Monitoring , author=P. Richard Warburton , date=July 2008 , journal=Managing Infection Control , url=http://www.chemdaq.com/newsite/wp-content/uploads/2016/04/The-Essentials-of-Sterilant-Gas-Monitoring.pdf Sterilization (microbiology) Occupational safety and health