Ethylene oxide (EtO) is a colorless, flammable gas widely used as a sterilizing agent in various industries, including the medical, pharmaceutical, chemical, and agricultural sectors. Due to its potential health risks, the Environmental Protection Agency (EPA) has established strict regulations to limit EtO emissions and maintain air quality. In this blog, we will discuss the key users of EtO, the impact of these regulations on air quality, the importance of using advanced detection methods like the phx42 FID to find leaks, and the necessity of continuing to monitor and enforce these standards.

1. Who Uses Ethylene Oxide and Its Health Risks

EtO is primarily used by several industries:

a. Medical and Pharmaceutical Industries:

EtO is a highly effective sterilizing agent, making it a popular choice for sterilizing medical equipment and pharmaceutical products that cannot withstand high temperatures or moisture. This includes items such as surgical instruments, sutures, catheters, and implantable medical devices.

b. Chemical Industry:

EtO is used as a precursor to produce ethylene glycol, a critical component in the manufacturing of products like antifreeze, polyester fibers, and plastic bottles. It is also used to manufacture other chemicals, such as surfactants, detergents, and adhesives.

c. Agriculture:

In some cases, EtO is used to fumigate and sterilize agricultural products, like spices and grains, to eliminate bacteria, fungi, and pests.

d. Food Packaging:

While less common, EtO may also be used to sterilize certain types of food packaging materials that are sensitive to heat or moisture.
EtO is classified as a carcinogenic substance, with long-term exposure linked to an increased risk of certain types of cancer, including leukemia and lymphomas. Additionally, acute exposure can cause respiratory irritation, headache, dizziness, and other neurological symptoms. Given these potential health impacts, it is crucial to regulate EtO emissions to protect both the environment and public health.

2. EPA Regulations on EtO Emissions

In 2008, the EPA revised the National Emission Standards for Hazardous Air Pollutants (NESHAP) to further limit EtO emissions from industrial sources. The 2008 regulations established stringent control measures for EtO emissions, including requirements for control devices, monitoring, recordkeeping, and reporting.

In response to growing concerns about the potential health risks of EtO exposure, the EPA has continued to strengthen its regulatory framework. In 2016, the EPA’s Integrated Risk Information System (IRIS) program updated its risk assessment for EtO, significantly lowering the acceptable exposure level.

3. The Impact of Regulations on Air Quality

Since the implementation of stricter EPA regulations, there has been a significant decrease in EtO emissions. Monitoring data indicates that facilities subject to NESHAP requirements have achieved substantial emission reductions, resulting in improved air quality in surrounding communities.

In addition to federal regulations, some states have adopted even more stringent standards for EtO emissions. This has led to further reductions in emissions and improvements in air quality at the state level.

4. Using phx42 FID to Detect Leaks and Limit Exposure

The phx42 Flame Ionization Detector (FID) is an advanced leak detection technology that helps industries reduce EtO emissions and limit human exposure to this hazardous substance. The device works by detecting organic compounds like EtO in the air and providing accurate, real-time measurements of their concentrations.

By utilizing the phx42 FID to identify and locate leaks in the equipment and processes that handle EtO, industries can quickly address and repair these issues, minimizing the release of EtO into the environment. This, in turn, leads to reduced emissions and improved air quality, thus protecting the health of workers and surrounding communities.

The use of advanced detection technologies like the phx42 FID is essential in ensuring the effectiveness of EPA regulations and meeting emission reduction goals. Moreover, these tools contribute to the ongoing efforts of industries to minimize their environmental impact and protect public health.


EPA regulations on EtO emissions have had a significant positive impact on air quality and public health. By establishing strict standards and consistently enforcing them, the EPA has been successful in reducing EtO emissions and limiting human exposure to this hazardous substance. The use of advanced leak detection technologies, such as the phx42 FID, plays a crucial role in identifying and mitigating EtO emissions, contributing to improved air quality and a safer environment. It is essential to continue monitoring and enforcing these regulations to maintain and enhance the progress achieved in air quality improvement, ensuring a healthier future for all.

We hope you will join us in welcoming the newest member of our merry band, Tori Duran.

Tori has joined as our Marketing Associate and Chateau Onboarding Coordinator.  From the very beginning, Tori has already made a tremendous contribution in working with prospects, customers and new Chateau users.  The best part is that she is keeping Rex super busy – which is a good thing for him!

We were all delighted that Tori got to coordinate our 16th Brownie Celebration as soon as she came on board. So she knows how this works: good things happen at LDARtools- and we all celebrate.

When asked what she likes best about her new role, Tori, said….

My favorite part about my new role at LDARtools is working with all of the remarkably intelligent, kind and enthusiastic people that make up the LDARtools team. LDARtools really does have some fascinating products and it’s all made that much better by the people who show up every day to make it work. Everyone has been so welcoming and it’s clear that they all love working here…and now I do too!

(Special personal update: on April 15, Tori’s last name will slide from “Duran” to “Moses” as she and Brendan (Rex and Valerie’s youngest son) are getting married. Pray for Tori- because Brendan is a piece of work!)

Thank you all for participating in our 16th Brownie Celebration. This was all possible because we had NO phx21s or phx42s in our repair lab, due to our experienced Level 1 Certified Repair Techs, enhanced automated support system, and improved technician training methods.

Nothing makes us happier than to see our customers enjoying their well-earned brownies. Special thanks to everyone who shared pictures with us! We hope you all will participate in our next one!

By Kilian Regan, Chief Product Officer, and Kevin Moses, Director of Operations, LDARtools

The year was 1996 and 11-year-old me (Kevin Moses), and my 9-year-old brother, were up to no good, or so we thought. Mom and Dad left us in the hands of our very capable teenage sister, who was undoubtedly talking on the cordless phone in her room. Recently Dad left a video in the VCR called “Fugitive Emissions” and this was the moment we had been waiting for.

Popcorn made, we sit down to what must certainly be a sequel to the 1993 Movie, “The Fugitive” with Harrison Ford. To our dismay, Harrison Ford never came on screen. 
I presume an important part of the aforementioned video (which as one can guess, we did not finish), was the dark art of emissions reporting. Much later in life, I, along with Kilian Regan (co-author) had the opportunity to learn a great deal about emissions estimating from the great Graham “Buzz” Harris while working on the development of the Chateau LDAR Software. There has been a lot of conversation recently about API fugitive emissions testing, but not as much about what happens after that. This article aims to share a high-level overview of how facilities report fugitive emissions to regulators.

Different Methods Available

The EPA provides a few ways emissions can be reported, and a facility must use the one that utilizes the best available data. Generally speaking, this will result in lower emissions being reported; the less data available, the more over-estimating will occur.
  1. The Correlation Equation method converts ppm to mass flow using equations provided by the EPA. This is the most common method used.
  2. The Average Emission Factors(AEF) method uses an industry average (generally determined by the EPA) to report unmeasured components. This method is used if components do not have monitoring (ppm) data.
  3. Others, such as >10,000ppm or < 10,000pmm (aka Leak, No Leak) OR AEF, are created using a facility’s historical data. These are largely unused and highly complex. They are mentioned only to highlight that they will not be covered in this overview.

The Correlation Equation

This method uses ppm values measured at each component in a correlation equation to report instantaneous emissions, then considers time in service (as well as some other factors) to get mass/time. The EPA has published the data needed to perform these calculations. Equations and values change based on industry, component type, and service.
  • Zero Readings Emission Rates. Assumes there is a very small leak on 0 reading components.
  • Peg Factors Emission Rates for analyzers that peg at 10,000ppm and 100,000ppm.
  • The ppm Correlation Equation for everything in between 0 and analyzer peg.​

The following is an example of a Valve in a refinery in Light Liquid Service:

  • Zero Reading Emission Rate: 7.8E-6 kg/hr
  • Pegged 10,000ppm: 0.064 kg/hr
  • Pegged 100,000ppm: 0.14 kg/hr
  • Correlation Equation: 2.29E-6(ppm)^0.746

Direct Measurement can also be used to replace or update the estimates. An example would be after finding a leak (ppm), another trip would be made to the component with a specialized device, such as a bagging kit or High Flow Sampler, that can capture all of the leak with a known amount of dilution. While the reading from the device is measured in concentration, the known dilution allows an accurate mass flow rate of the leak to be calculated.

Fig 1

Calculating Emissions Between Data Points

Linear interpolation (trapezoid) is the most commonly used calculation method and assumes that emission rates increase/decrease linearly between routine data points. As with almost everything about emission reporting of fugitives, the only thing known, is the likelihood it is not actually true. The change in the leak was almost certainly caused by an event, but there is no way to prove this with the data available.

There are exceptions to the linear assumption. One example is the emissions after a leak and before a repair attempt. The emissions rate is assumed to continue at the same rate until the repair attempt, as logic would suggest. See Chart 1 for an illustration of this.

Other methods of calculating the emissions between data points exist, but result in total emissions being essentially the same over time. The important issue is to not change calculation methods from one period to the next, as doing so could impact overall reported emissions.
One interesting thing about these calculations, as well as an example of complexity, is that data before and after the reporting period is needed to calculate the time-weighted emissions. For example,  if a connector was monitored once in 2021, the calculator must look to 2020 data to get a starting point for the line. It will also look to 2022, and if there is no data yet, the line will continue straight. This means the calculated emissions for 2021 would change every time there is new monitoring on any annual component in 2022. See Chart 1 for an illustration of this.

Chateau Fugitive Emissions Example

This is the simplest and most emissions overestimating method. It involves looking up a rate by industry, component type, and service, and multiplying by hours in service. It is used most commonly on connectors that do not require inspections or for heavy liquid components. There is almost always a large overreporting using this method as the emission factors were developed before any LDAR programs were in place, and used data from components that had never been inspected for leaks. In some cases, credits can be applied to this population of components if certain controls are in place.

Fig 3

Author’s Note

There are a lot of “always — except if” in the emissions estimating world. There is competing data published by the EPA, and the State Agencies, making it very complex. This article is a general overview of the art and is not intended to be advice or instruction. To learn more about fugitive emissions and how to handle this complexity, please contact an LDAR managing company.
Originally published by The Fugitive Emissions Journal

Since joining LDARtools in July 2021, Glen has distinguished himself as a valuable member of LDARtools.

He has played a key role in selecting and implementing the new talentLMS learning system, configuring our new online Knowledge Base for Chateau (and other software products), as well as streamlining our internal document management process.

His attention to detail and leadership have been huge assets for each project, and as recognition for his extraordinary efforts, he has been promoted to the position of Document Manager.

We look forward to his continued contributions.

Congratulations to Glen!

On January 2nd, 2023, there were NO phx21 or phx42s in our Repair lab.
Thank you to all the phx21 & phx42 Level 1 Techs and users. As a result of continued teamwork and diligence, this is all possible.

We hope you’ll be a part of this celebration!
Click here to RSVP before February 28th

You can also email to RSVP.

Please include “Brownie Celebration RSVP” in the email subject line.

Please also provide the following information in the body of your email:

City, State  ZIP
Street Address Line 1
Street Address Line 2
Complete shipping address (cannot be a PO Box)
Email address
First and Last Name
Site ID or Company Name
Number of phx21 & phx42 friends will be at your celebration (48 max)
Thank you again to all the phx21 & phx42 Level 1 Techs and users.

The link is active until February 28th.

Please see below for details on our holiday hours and operations.

Monday, December 26, 2022

  1. Warehouse open  8 a.m. – 5 p.m.
  2. Customer drop-offs/pickups only
  3. No FedEx or UPS deliveries/pickups

Tuesday, December 27, 2022

  1. Warehouse open 8 a.m. – 5 p.m.
  2. All normal shipping operations resume

Friday, December 30, 2022

  1. Warehouse open 8 a.m. – 3 p.m.
  2. Normal shipping operations during business hours

Monday, January 2, 2023

  1. Warehouse open  8 a.m. – 5 p.m.
  2. Customer drop-offs/pickups only
  3. No FedEx or UPS deliveries/pickups

Tuesday, January 3, 2023

  1. Warehouse open 8 a.m. – 5 p.m.
  2. All normal shipping operations resume

Have a blessed and safe holiday.

Thank you to everyone who participated in our first Annual phx Tech Tip Contest. We had great inquiries, and have found our top three winners.

  • First grand prize winner of $250 is Josolyn Rodriquez with HPC Industrial Group. Her ideas and presentation were spectacular. Congratulations!
  • Second winner is Ann McKeon with Renewable Energy Group. Thank you so much for your contributions and recommendations!
  • Third winner is Barry Selcer with HPC Industrial Group. We appreciate your ideas and participation!

We hope you all and more participate again next year!

We recently delivered our 1000th phx42 to a lucky customer. We are super excited about the news.

We would like to say thank you to all of our suppliers, distributors, and most importantly, our customers.


Happy Labor Day from LDARtools!

We’ll be closed on Monday. If you need assistance over the long weekend to meet a compliance deadline, please call 877-788-1110 ext. 704 and we will do our best to find someone to help you.