Sulfur Content in Diesel Fuel: Limits and Regulations

EPA Regulations and The Clean Air Act

Since the 1990s, diesel fuel quality has been an essential topic of discussion due to the increased regulations that the U.S. EPA has implemented over the years as a result of the Clean Air Act (CAA). One of the main goals of this Act was to set and achieve National Ambient Air Quality Standards (NAAQS) in every state. The 1990 CAA amendments were later revised to include the issuance of technology-based standards that require the maximum degree of reduction of emissions of hazardous air pollutants. New regulations meant engine manufacturers and diesel fuel producers would have to work together to determine how to meet the new standards best.

Effects of Emission Regulations on Diesel Fuel

The most easily attainable and regulated fuel property that the EPA regulated in the 90’s was sulfur content. Historically, ASTM standards have limited sulfur content to .5% (wt.). A few years later, in October 1993, a limit for Low Sulfur diesel fuel was introduced as 500 ppm = 0.05% (wt.) to facilitate the particulate sulfate reductions to meet the emissions standards.

Fast forward to June 2006, the maximum sulfur level in the U.S. was reduced to 15 ppm (Ultra Low Sulfur Diesel) for on road (highway) diesel engines and fuel supplies and was subsequently adopted by all nonroad, locomotive and marine (NRLM) diesel fuel and equipment in 2014. In addition, the regulations prompted engine manufacturers to deploy catalyst-based emission control devices, such as NOx absorbers and Diesel Particulate Filters (DPF), to meet new diesel emission tier standards.

Sulfur emission reduction has also been an important subject for the maritime industry. In 2010, marine standards that were previously exempt were further reduced from previous levels to 1,000 ppm within the Sulfur Emissions Control Areas (SECAs) for North America and the U.S. Caribbean Sea. In January 2020, new international rules put forth under the International Maritime Organization also reduced the global sulfur limit (outside SECAs) in marine fuels to 0.5% or 5000 ppm (down from 3.5%), and the change is expected to have a ripple effect throughout the fuel industry.

The U.S. Energy Information Administration (EIA) has noted that the change in sulfur limits has wide-ranging repercussions for the global refining and shipping industries, as well as petroleum supply, demand, trade flows and prices. From market disruptions from the COVID pandemic and today’s economic pressures on buying and selling bulk diesel fuel to meet demands, monitoring the sulfur content of your diesel fuel is still important decades after emission standards were implemented.

Reducing sulfur content in diesel fuel has placed a new demand on diesel engines and emission control systems in operation today. Factoring in the aging and foreign fuel supplies in circulation and storage, along with the ever-changing regulations means ensuring that equipment fuel supplies meet the required specifications is now necessary.

Check out our recommended testing for diesel fuels here.

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Published February 3, 2023

Impact of Cold Temperatures on Your Cooling System

Coolant analysis can shed light on developing internal problems and catch concerns early before harmful problems can occur. Making the proper adjustments, when needed, is critical for maintaining proper cooling system performance.

How do Temperatures Affect Coolant?

When outside temperatures drop, proper freeze protection is required to avoid freezing or lack of coolant flow within the cooling system. When coolant freezes, it is most likely due to improper water-to-glycol ratio in the cooling system. Freezing can cause cracking and damage to the engine block and/or cooler allowing coolant and lubricant to mix. Once lubricant and coolant mix, further damage to the asset will occur leading to an expensive unexpected repair.

Finding the Proper Glycol Mixture

The proper glycol mixture with the water is crucial. Testing and maintaining the proper dilution provides a lower freeze protection, while also maintaining proper coolant properties. Water by itself has a freeze point of 32 degrees Fahrenheit (0 degrees Celsius). Using only water or too much water dilution will lower other coolant protection properties and can lead to system corrosion and lower than desirable pH control. However, too much glycol can cause the coolant to become too viscous, slow down coolant flow within the system and an over-saturation of corrosion inhibitors resulting in a precipitation concern. Plugging and/or inadequate coolant flow will impact proper protection for the cooling system and increase the time needed for the engine to reach proper operating temperatures. Lubricant not reaching proper temperatures allows for more metal-to-metal contact and engine wear concerns.

Routinely Test Your Cooling System to Avoid Problems

Overall, roughly 40% or so of preventable engine failures occur due to the cooling system not functioning properly. Most concerns in the cooling system are created by improper maintenance of the cooling system and coolant in service. Coolant chemistry reactions occur due to mechanical issues, coolant properties not being maintained and/or contamination of the system.

Learn more and find answers to your coolant testing and analysis questions here.

A proper fluid analysis program should include testing all fluids in the asset to have a better understanding of the fluid and equipment health. With trend analysis, you can catch concerns easier and faster and be able to take action on the proper recommendations to identify and address the issue before you have expensive, unexpected equipment downtime.

Winter temperatures should not keep your equipment out of service. Reach out today and pull a coolant sample to take out the guesswork out of knowing if the coolant in the system meets requirements for properly protecting your cooling system.

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Published January 10, 2023

Are You Certified in Oil Analysis?

Today’s oil analysis capabilities offer a great deal more than just monitoring component health. With today’s technology, along with performing the proper tests, we can:

  • Monitor the condition of the oil
  • See if it is suitable for continued use
  • Reduce the amount of used oil disposal
  • Adjust maintenance intervals
  • Adjust component replacement schedules
  • Improve forecasting and budgeting
  • Increase component life hours

With all of this in mind, it begs the question, are you able to maximize the return on investment from your oil analysis program? I believe the answer to this question would be for you to become certified as an Oil Monitoring Analyst (OMA I) via the Society of Tribologists and Lubrication Engineers (STLE).

What is an Oil Monitoring Analyst (OMA I)?

Predictive maintenance professionals who oversee the oil analysis program for a shop/plant would be suited for OMA I certification. At POLARIS we call this person a Program Champion. At POLARIS we believe the single most important ingredient in a successful oil analysis program is the Program Champion inside it. OMA I certification might also be beneficial for other members of a maintenance team to obtain as well (i.e. mechanics, operators, engineers, etc.). Anyone with the following core responsibilities would be a viable candidate for OMA 1 certification:

  • Responsible for oil sampling
  • Reviews oil analysis reports and performs the correct tests
  • Maintains overall care of equipment and maintenance actions

Becoming OMA I Certified

OMA I certification is obtained by scoring 70 percent or higher on the designated exam that standardizes the body of knowledge for an Oil Monitoring Analyst. Once obtained, the certification is valid for three(3) years, after which individuals are required to recertify to maintain their OMA I status.

OMA I Exam Topics

  • Sampling
  • Application/Test Methods
  • Data Interpretation
  • Troubleshooting
  • Lubrication Fundamentals


  • 16 hours of training in oil analysis-related courses, which may include company training programs
  • One year of experience utilizing oil analysis in the field of lubrication

Society of Tribologists & Lubrication Engineers (STLE)

So what are you waiting for? Get your Oil Monitoring Analyst I (OMA I) certification today. Visit the STLE website for a list of recommended reading materials for certification.

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Published December 23, 2022

ATP (Adenosine Triphosphate) Content Testing for Diesel Fuels

Do You Know What’s Happening in Your Diesel Fuel?

Ultra-low sulfur diesel and biodiesel fuel are particularly vulnerable to water contamination during transport and storage. Once water gets into the diesel fuel system, it creates the opportunity for an invasion of microorganisms. Microbes attack the fuel/water interface, where they thrive and multiply. Once established, they embed themselves in a thick layer of slimy deposits, creating several troublesome maintenance problems, including premature fuel filter plugging, clogged injectors, fuel storage tank corrosion, and leakage.

Proactively Detect Potential Microbial Activity

The new ATP (Adenosine Triphosphate) Content Test measures ATP, the primary component found in cells responsible for transferring energy in living organisms. An accurate measurement of ATP within diesel fuel provides a clear indication of when action should be taken to mitigate unwanted, harmful biological growth in the fuel system or tank.

With this new laboratory test, your sample’s results and analysis are are available faster compared to standard turnaround time for bacteria, fungi and mold testing included in basic diesel fuel test packages.

Click to View the ATP  Content Testing Technical Bulletin

If you’re interested in this new test, please reach out to your account manager or email

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Published December 8, 2022

Coming Soon: New Diesel Fuel Sample Bottle

In the coming months, customers who are testing diesel fuel will see a change in their diesel fuel test kits. The kits will include a smaller-sized metal sample bottle (a 500 mL rather than a 750 mL bottle). This new bottle can be used for collecting and sending in diesel fuel samples for all routine diesel fuel testing packages. Through recently implemented changes in diesel fuel testing procedures in the laboratory, the amount of diesel fuel required to perform testing has been reduced.

  • Smaller collection bottle means less diesel fuel from your machine
  • Reduction in the bottle size means lower shipping costs and less environmental waste
  • There will be no changes to test packages or kits, customers will begin to see the new bottle within newly ordered kits


If you have any questions, please reach out to our customer experience team at or by phone 1.317.808.3750 (Monday – Friday, 7:30 a.m. – 7:00 p.m. ET)

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Let us prove it to you.

Published November 1, 2022

Program Insights: Time to Make Adjustments and Improvements

How many times have you heard “in these unprecedented times” since 2020? Well the precedent has been set, times have changed and they are not going to change back…

The reality is: labor shortages are requiring staff to become more creative, oil supply has forced companies to extend their drains, equipment availability lead times are so far out that new equipment is not an option (even if you could, interest rates are continuing to rise). In addition to these challenges, parts and service are driving downtimes to be longer and longer. The truth is, these challenges are not going away anytime soon. So, what can you do now to solve some of these challenges?

Your Maintenance Program Isn’t the Same Anymore

You simply cannot hold on to the maintenance program you had in the past. Your program needs to be proactive – even world-class preventive maintenance programs are changing. Programs are finding new ways to drive efficiency, reduce rework and keep expenses down – all while keeping production up. These programs regularly turn to the experts at POLARIS Laboratories® to learn how they can keep being the best.

What Can You Do Today?

Programs that are seeing positive improvements and big impact aren’t making groundbreaking changes, they are making small, incremental changes that result in big impact, such as:

  1. Participating in our extended drain comments program to prolong the life of their oils
  2. Adding sampling valves to equipment to provide an accurate, consistent sample in half the time
  3. Scheduling quarterly Program Enrichment Reviews to learn what issues occur the most and on what pieces of equipment
  4. Discovering new tools and ways to integrate data to drive efficiency and effectiveness

Slow Down to Speed Up

In business it has been said “sometimes you need to slow down to speed up”.  When was the last time you asked for expert advice on how to improve your program? We know how busy you are, we understand the pressures of outside factors on your daily workload. The good news is, even though you may have hundreds of things to worry about and take care of, POLARIS Laboratories® has one focus: your preventive maintenance.

Call us today and talk to our experienced Reliability team. Ask their advice what you can do to make an impact and alleviate your maintenance challenges. They are here to help you implement a better program. As mentioned at the start of this blog, the unprecedented times are now precedented.  Things will only change if we do. Call us at 877-808-3750 or fill out our contact form – we’re here to help.

Proven Impact. Proven Uptime. Proven Savings.
Let us prove it to you.

Addressing Industry-Specific Coolant Concerns with Analysis

Maintaining your cooling system does not have to be a complicated task or result in a neglected system. Understanding the fluid and equipment needs are key to proper maintenance in the field. With proper maintenance, the fluid and equipment health can provide the adequate functions to protect and remove heat from the component parts as needed.

Different applications and environments play a critical role and can exacerbate potential problems that may hinder the cooling systems ability to circulate, remove heat and then dissipate the heat before circulating again through the system. These functions are critical for the cooling system to maintain and protect the equipment. Adequate coolant testing based on industry can identify possible issues and/or concerns. Because the fluid chemistry plays a critical role in the cooling system’s ability to transfer heat and prevent corrosion which protects overall system health.


In today’s market, there is a high demand to maintain equipment. The average life for most fleets is 3.5 to 4 years, however, due to supply issues and current economic conditions, many are looking to extend the life of their fleet. Common coolant system concerns that can result in issues are often overlooked until failure occurs. These concerns can be monitored as part of an effective predictive maintenance program:

  • High Temperature Issues
    • Glycol concentration
  • Chemistry Issues
    • Corrosion inhibitor
    • Mixing
  • Contamination
    • Scale hardness
    • Glycol degradation


Higher ambient temperatures in different equipment types may require different fluids to maintain system temperatures. Monitoring and knowing the fluid types are key for proper maintenance. Common coolant system concerns to monitor include:

  • OEM Requirements and Coolant Supplier Support
    • Understanding equipment recommendation for glycol to water concentrations
  • Contamination Issues
    • Scale hardness
    • Glycol degradation

Power Generation

The duty cycle for this industry is “long term, low maintenance” requiring a focus on the coolant chemistry. Typically, fluids in the system are in a state of inactivity. Operating only when needed, when serviced or when demand is required. Common coolant concerns to monitor are:

  • Contamination
    • Degradation acids
    • Grounding concerns
    • Air leak
    • Scale
  • High temperature
    • Glycol concentration
      • Maintain proper OEM glycol to water concentration
    • Chemistry issues:
      • Corrosion inhibitor
      • Mixing


The marine industry encompasses a large range of coolant systems; however, these systems will be deployed with very little access to repair parts or facilities for extended times. Increasing the system’s integrity is critical. There is a wide variety of coolant formulations to meet proper regulations and knowing the coolant formulation is key for making adjustments when needed.

  • Chemistry issues
    • Mixing
    • Maintaining proper fluid corrosion inhibitor levels
    • Understanding equipment recommendation for glycol to water concentrations
  • Contamination issues
    • Air leaks
    • Internal/External contamination concerns


With concerns of raising inflation, high fuel prices and changes in supply availability demands, keeping equipment in operation and extending all fluid life are becoming more of a necessity. Common coolant system concerns (often overlooked until related failure occurs) can be monitored as part of an effective predictive maintenance program.

  • High Temperature Issues
    • Glycol concentration
      • Freeze point and boil point protection
    • Chemistry issues
      • Corrosion inhibitor
      • Mixing
    • Contamination
      • Scale hardness
      • Glycol degradation

Learn more about test methods for coolants here.

Overall, all industries will have similar goals to maintain equipment and get the full life from the equipment as expected, if not longer. With proper fluid analysis and monitoring, concerns can be identified early before further damage internal causes a premature failure.

If you’re interested in learning more about recommended coolant testing and analysis for different industries, sign up for our upcoming webinar What Coolant Testing is Right for You? on August 25, 2022 at 11 a.m. ET.

Register Here

Reach out to our team to see how we can support your fluid analysis program and help increase uptime in your fleet.

Contact Us

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Published July 28, 2022

A Program Snapshot: HORIZON® Management Reports for Lube Marketers

The HORIZON data management system is robust in all that it can provide to a fluid analysis program. Team training is conducted on features like the Dashboard, Reading a Sample Report, Equipment List Management, Mobile App and Sample Submission – which are all important for program success. But, one feature of HORIZON that is often underutilized or undertrained is Management Reports. These reports provide lube marketers and program champions an overview of their fluid analysis program and provides specific areas for improvement.

There are twelve management report options in HORIZON. This means you can view twelve different sets of data in different areas of your program. For lubricant marketers specifically, the information provided in these reports can provide a look at how distributors and end users are utilizing their fluid analysis programs offered through the lube manufacturer.

Out of the twelve reports, there are three that I believe have significant value when it comes to information lube marketers are looking for: Program Condition, Turnaround Time and Severity Summary. A lubricant marketer can use the information provided in these reports as a touchpoint by sharing a snapshot of the overall program. This ensures the loyalty and pride in their product and the information provided will show that their distributors and end users are successfully monitoring the condition of their equipment.

Program Condition Report

When reviewing the first section of the Program Condition Report, components due/overdue, you can see if the equipment is being tested and if the integrity of equipment is still in tack. The program condition data tells you if the team is being compliant and testing regularly – and it can be the starting point to set a trackable goal.

Turnaround Time Report

The Turnaround Time Report is crucial to program success, too. The information provided in this report reassures the laboratory is meeting their goal and the samples are getting to the laboratory within five days of sample being collected.

The report helps identify areas of improvement, for example, shipping challenges. The graph provides a topic of conversation that some folks may not think about: the importance of getting samples to the laboratory as soon as possible to get results fast and avoid any potential downtime.

Severity Summary Report

The Severity Summary Report will help identify trending of the results, either up or down. This allows the users get in front of a potential problem and help identify some actions that needs to be taken. This opens up a discussion of the lubricants and where some improvements can be made.


If you are a lubricant marketer, I encourage you take a look at the management reports HORIZON offers. These reports make it easy to get a high-level overview of your customers, distributors and end users’ use of their fluid analysis program. If you need assistance, reach out to your account manager!

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Let us prove it to you.

Published July 15, 2022

Don’t Delay When it Comes to Your Fuel Reports

Read Your Reports

Read your analysis reports as soon as you get them. If you took the time to test your fuel that means you’re trying to avoid an issue (clogging fuel filters, injector warranties) or you’re looking to troubleshoot problems you’re experiencing (lack of power, fuel quality concerns). Don’t wait until it’s too late before you evaluate your report results – failure can occur at any moment.

Review the Test Data

On analysis reports, test values that have diagnostic significance will be flagged or highlighted in some way (boldface type, color coded, etc.). You should begin your review with analyzing these flagged results.

Review each test value individually and then look for coordinating data that can help confirm the analysis. Knowing your test properties will help tremendously with understanding the test results. If you’re unsure or need help interpreting results, you can contact the laboratory for more explanation. A quality, dependable laboratory will spent the time helping you understand the analysis.

Analyze the Analyst’s Comments

After reviewing the data, it’s then time to look at the data analysts’ comments. Many laboratories set the overall severity based on the analyst’s interpretation of the results, rather than one single severe reported limit. The comments will outline the wear patterns, if applicable, then the condition of the fluid. These comments can also include sources of contamination and recommended maintenance actions.

Ensure Sample Information Accuracy

If incomplete information was provided for the sample, the analysts cannot provide a quality and effective analysis of your fuel. Simply submitting the sample as “diesel fuel” limits the analysis because there are different grades of diesel fuel (ULS #1, #2) and each have separate ASTM alarm limits. If needed, contact the laboratory to provide updated information and then ask for a re-evaluation of the sample.

Provide Feedback to the Laboratory

Feedback on test results and maintenance actions provided to the laboratory is crucial to effectively understanding and managing your fuel program. Laboratories test your fuel with the intention of providing you with accurate, reliable and timely results so you can maximize your Return Of Investment (ROI) of your program. In order for the laboratory to help improve your program, it’s important to open the lines of communication when it comes to results and actions taken by your team.

Download How to Read a Diesel Fuel Report

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Published June 13, 2022

Will You Accept Your Reliability Mission this October?

The maintenance and reliability world is rapidly progressing with technology advancements and new digital solutions to integrate programs and data. We’re committed to help you, our customer, leverage these new advancements and innovations and achieve optimal equipment reliability.

Mission: Reliability, the 7th-annual Customer Summit, will focus on providing you the tools, resources and education so you can bring your program full circle.

Experience a Summit Like No Other

Mission: Reliability, taking place in Indianapolis October 3-5, will be unlike any Customer Summit to date or maintenance conference in the industry. Attendees will gain a full circle experience and see all aspects of maintenance and equipment management; from the lubricant manufacture, to the original equipment manufacturer, to the oil analysis provider, to seamless integration solutions.

In addition to keynote speakers, general and breakout sessions, workshops and networking, POLARIS Laboratories® has partnered with Allison Transmission and Cummins, to provide additional education and tour opportunities for Summit attendees. These exclusive OEM tours include:

  • Allison Transmission
    • Innovation Center (Indianapolis, IN)
    • Electrification and Environmental Center (Indianapolis, IN)
  • Cummins
    • Technical Center (Columbus, IN)
    • Augmented and Virtual Environment Lab (Columbus, IN)

During these tours, Mission: Reliability attendees will get a first-hand look at manufacturing and technology innovations these OEMs are putting in place to prepare for the future of equipment reliability.

We’re excited to bring these additional learning experiences to this year’s attendees and hope you will join us for Mission: Reliability in October. Will you accept your mission?

Proven Impact. Proven Uptime. Proven Savings.
Let us prove it to you.

Published June 9, 2022