drumAlternate Operating Scenarios (AOS) and Maintenance, Startup, Shutdown (MSS) events are some of the most discussed topics among Oil & Gas manufacturers and their regulators, and it’s a topic ERA Environmental has covered on its industry advice blog too.

    If you need to learn more about the role of AOS and MSS for your facility, we suggest you start with ERA’s free guide to Oil & Gas Compliance Challenges, or read through our quick primer article. Today’s article will focus on some small best practice tips and advice to make managing your AOS / MSS reporting and tracking even easier (and more cost-effective too).

    Don’t Fear the Regulator

    Being confused about the difference between an AOS and MSS, or not knowing under which category to report emissions from a certain operating scenario is nothing to be ashamed of, and it’s not something your regulators will penalize you for if you come to them for advice. In fact, in many cases where Oil & Gas air regulations are changing, state regulators are in the same boat and would be happy to work with you to create some regulatory clarity.

    Unfortunately, many Oil & Gas EHS Managers are afraid to come to their state regulators with questions about MSS and AOS because they fear it will prompt a full investigation into a facility or be used as an admission of guilt for future deviations. These fears are unfounded.

    Regulators are a vital resource to manufacturers that want to do good business, stay compliant with air emissions regulations, and put in an honest effort into compliance even when they aren’t 100% sure how. Regulators aren’t out to catch or snare EHS Manufacturers that need help - all regulators want is to help you be in compliance.

    That being said, to have a good relationship with your regulators you do need to have good record keeping practices and are able to provide all of the information they need to do their jobs. It’s only when gaps in your record keeping appear that regulators become wary. If you aren’t sure how to categorize air emissions generated from an on-site activity, you had better know which type of emissions and what quantity was released before you ask your regulators for assistance.  

    It’s also always better to ask for clarification before taking an action than asking a regulator for forgiveness after the fact.

    AOS/MSS Deviations: When in Doubt, Report - Accurately

    It is no secret that whenever something goes wrong and you release unauthorized emissions during an AOS or MSS activity, your best choice is to be 100% transparent and report those emissions to your state regulator as quickly as possible. There is never any benefit to sweeping those emissions under the rug. Even if you’re not sure how to categorize the deviation, or if you’re not positive it should be considered a deviation, getting a notification in writing in front of your regulators is the safest and most responsible route. They will be able to help you sort things out after the deviation notification in order to minimize or avoid noncompliance fines.

    However, ERA Environmental also advises manufacturers to take the time to ensure the emissions you do report in that deviation notification are as accurate as possible - if you’re using an automated reporting platform this will only take a few minutes and won’t jeopardize your notification timeline. Submitting an inaccurate deviation notification is not in your best interest in the long term.

    Sometimes EH&S Managers grossly overestimate the resulting emissions in order to avoid underreporting and creating more trouble for themselves. However, overestimating too much triggers increased regulator scrutiny, urgency, and increased potential fines. Being conservative and overestimating is still acceptable, but having an accurate report  that doesn’t over- or underestimate is even better.

    Instead of guessing, have a system in place that can accurately track and report emissions from an AOS or MSS activity on demand. This typically means having an automated EHS platform that is capable of virtual process mapping - modelling out the emission factors and processes of any potential AOS or MSS set up and tapping into Continuous Monitoring System (CMS) data.

    When you provide an accurate and realistic report within the required deviation notice timeline, it shows your regulators that you have taken the event seriously, are on top of your emission data, and are trustworthy. It also saves you the time of having to revisit the event afterwards to generate the “real” emissions report… you’ll already have the real world data from the get go.

    Get Authorized MSS and AOS in Writing

    If you have a large number of MSS activities to plan for and write into your permit, or if your facility is one that experienced a change in MSS state regulations (like Oil & Gas facilities in Texas, all of which had to get their planned MSS events authorized by January 5th, 2014), you may be unclear which of your MSS activities have been authorized by your regulators.

    The simplest solution is to ask your regulator for a document outlining which of your activities have been approved. It doesn’t need to be as complex as your Title V permit, just a bare-bones outline of authorized MSS activities (and their approved schedules) and AOSs (of which there can be many). Keep this document handy and accessible in a centralized file sharing system so that anyone who might need to can access it.

    If you’re in the process of rewriting/modifying your permits, applying for a new permit, or adding new MSS/AOS to your permits, it will be important to know which activities are already authorized.

    ERA recommends that you write in as many potential MSS and AOS setups as possible and get them authorized so that you’ll be covered for nearly any situation, and that means it can get more difficult to know what was already authorized in your permits, what has been approved recently, and what is pending approval.

    Although your Title V permit will also need to contain these approved activities, it can be much easier to keep track of them if they are also contained in a second, streamlined document. The hours saved from digging through a long operating permit could have a significant impact if you were faced with an unplanned MSS event or other emergency requiring an AOS to be run.

    It’s about getting your MSS and AOS information put down in writing in the simplest way possible. Not only will you get a clear picture of your acceptable actions, but it will make the  audit process much faster if a regulator comes to check in.

    Document Before, During, and After Any MSS Activity or AOS

    Documentation is usually the last thing on an EHS manager’s mind when there’s a malfunction or significant maintenance event happening in their facility. Our first instinct in an EH&S crisis is to act quickly to resolve the issue, minimize damage, and cease the release of emissions. And those should all be top priorities.

    But documenting your actions, the emissions, and the timeline must also be on that top tier of priorities. No matter how well you manage an emergency on site, your regulators only have your documentation as proof. You could have done everything right, but without the paperwork to prove it, it’s as if your proper response never happened at all.

    So get everything down in writing the moment it happens so that you can have a real-time report of how you handled the MSS activity or ran the AOS according to federal and state regulations.

    This real-time report includes the before, during, and after operations of your facility. Each one is essential for demonstrating that unplanned MSS events were unanticipated and unpreventable and that you made the right decisions given the information at hand.

    For example, if you have Continuous Monitoring Systems in place that are notifying you the minute a flare stops operating at a minimum regulated combustion temperature, you should look back on the flare’s record for the hours before the MSS event to determine the event’s history before it required attention.

    It’s also essential to record the “Close-Out” of any MSS or AOS: when the event ended, sign off on every action taken, do a damage report, hours worked, and a root cause analysis. Many of these steps get forgotten for non-emergency tasks like planned routine maintenance. Although you may not need to collect the same information for a planned MSS emissions report versus an unplanned MSS deviation report, it’s always better to keep the most comprehensive records possible, even if it’s just for your internal tracking.

    Get Your Free Copy: AOS & MSS Reporting Guide

    Ask an ERA Expert:

    Do you have any questions or concerns about the topic covered in this article? Want more insight? Now is your chance to ask one of ERA’s Environmental Specialists. Please leave your question or comment below and we’ll make sure one of our expert scientists responds. 

    Image Credit: Laughlin Elkind (creative commons)


    This Blog Was Co-Authored By:



    Alex Chamberlain
    Post by Alex Chamberlain
    June 26, 2014
    Alex Chamberlain is a writer for ERA Environmental Management Solutions.