Shell Midstream Partners L P : Hurricane Ida Operational Update #3

Update 3

September 20, 2021

Shell Midstream Partners, L.P. (NYSE:SHLX) ("Shell Midstream Partners" or the "Partnership") and Shell Pipeline Company LP ("SPLC") have substantially completed Hurricane Ida impact assessments on most of their owned or operated assets in the Gulf of Mexico and onshore Louisiana. The Partnership can report the following at this time:

• Gulf of Mexico Pipelines:

1. The Partnership's operated pipelines, including Amberjack, Auger, Mattox, Proteus, Endymion, Odyssey, Delta and Na Kika, have been returned to normal operating service after successfully completing all needed safety and stand-up tests.

• 1. Mars: Shell Offshore Inc. and SPLC have conducted a comprehensive damage assessment on the West Delta-143("WD-143") offshore facilities.
  2. • Due to the damage discovered, it is estimated that some parts of the WD-143 facilities will be offline for repairs into Q4 2021 and other parts until the end of Q4 2021. This damage will impact the Partnership's ability to provide service to shippers until such repairs are completed.
     • Given the timeline for repairs to WD-143, the Partnership expects throughput to resume from the Olympus platform at some point in Q4 2021 and from the Mars and Ursa facilities at some point in Q1 2022.
• Onshore Assets:
• 1. The Zydeco pipeline has been returned to full capability and is operating under normal conditions.

Shell Midstream Partners carries several insurance policies in kinds and amounts customary to the industry, which may offset some costs of any asset damage and business losses. The Partnership's business interruption insurance related to lost revenue is expected to begin after sixty days of downtime. The Partnership intends to file all appropriate claims.

The Partnership will continue to provide updates on the company website,

www.shellmidstreampartners.com,as information becomes available.

Shell Midstream Partners' primary focus continues to be the safety of its affiliates' employees and the protection of the environment.

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Update 2

September 10, 2021

Shell Midstream Partners, L.P. (NYSE:SHLX) ("Shell Midstream Partners" or the "Partnership") and Shell Pipeline Company LP ("SPLC") are continuing to perform Hurricane Ida impact assessments on all of their owned or operated assets in the Gulf of Mexico and onshore Louisiana. The Partnership can report the following at this time:

• Gulf of Mexico Pipelines:

1. Amberjack: The pipeline system has been successfully re-staffed and safety assessments are complete. The line is back in service with availability to deliver to Ship Shoal 332 and further into other downstream pipelines. At this time, downstream service to Fourchon station is not available. Crews have been mobilized, and they are continuing to assess and remediate issues at Fourchon station.

1. The Partnership's operated pipelines, including Auger, Mattox, Proteus, Endymion, Odyssey, Delta and Na Kika, are currently in various stages of re-staffing,re-supplying and performing ongoing safety and stand-up tests. The Partnership expects that these systems will begin returning to commercial service within the next week.

• 1. Mars: All parties are continuing to assess and determine the extent of damage to the SPLC operated West Delta 143 facilities, as well as when it will be safe to return to service. Today, Shell Offshore Inc. ("SOI") provided notice to Mars Oil Pipeline Company ("Mars") that, effective as of August 29, 2021, Hurricane Ida constituted an event of force majeure under certain agreements between SOI and Mars, damaging the West Delta 143 facilities and causing a shut-down of such facilities for an unknown duration.
• Onshore Assets:

1. Commercial power has been restored to Houma, and Zydeco is in the process of ramping up to full capability.

The Partnership will continue to provide updates on the company website,

www.shellmidstreampartners.com,as information becomes available.

Shell Midstream Partners' primary focus continues to be the safety of its affiliates' employees and the protection of the environment.

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Update 1 - Press Release

September 02, 2021

Shell Midstream Partners, L.P. (NYSE:SHLX) ("Shell Midstream Partners" or the "Partnership") and Shell Pipeline Company, L.P. are currently working to perform Hurricane Ida impact assessments on all of their owned or operated assets in the Gulf of Mexico and onshore Louisiana. Following initial high-level assessments, the Partnership can report the following at this time:

• Gulf of Mexico Pipelines: Initial flyovers have indicated that there was damage to the West Delta-143 facilities, which are operated by Shell Pipeline Company, L.P. and serve as a transfer station for the Mars Oil Pipeline for production in the Mars corridor. All parties are continuing to assess and determine the extent of such damage, as well as when it will be safe to return such facilities to service.
• Onshore Assets: Operations and maintenance crews are assessing assets and rights-of-way as they are able to gain access to southern Louisiana locations. We are currently assessing the full impact on our systems and when it will be safe to re-start.
• Refined Products Systems: Colonial Pipeline Company's Lines 1 and 2 have been restored after a precautionary shut-down prior to the storm and are now operational. The Partnership owns an interest in Colonial Pipeline Company's parent company, Colonial Enterprises, Inc. Further information can be found at https://www.colpipe.com/news/press-releases/colonial-pipeline-restores-lines-1-2-to-safe-operating-conditions-following-historic-storm.

Shell Midstream Partners carries several insurance policies in kinds and amounts customary to the industry, which may offset some costs of any asset damage and business losses. The Partnership plans to file any appropriate claims under such policies.

The Partnership will continue to provide updates as information becomes available on the company website, www.shellmidstreampartners.com.

Shell Midstream Partners' primary focus continues to be the safety of its affiliates' employees and the protection of the environment.

FORWARD LOOKING STATEMENTS

This press release includes various "forward-looking statements" within the meaning of the Securities Act of 1933, as amended, and the Securities Exchange Act of 1934, as amended. All statements other than statements of historical fact are, or may be deemed to be, forward-looking statements. Forward-looking statements are statements of future expectations that are based on management's current expectations and assumptions and involve known and unknown risks and uncertainties that could cause actual results, performance or events to differ materially from those expressed or implied in these statements. Forward- looking statements include, among other things, statements concerning management's expectations, beliefs, estimates, forecasts, projections and assumptions. You can identify our forward-looking statements by words such as "anticipate," "believe," "estimate," "budget," "continue," "potential," "guidance," "effort," "expect," "forecast," "goals," "objectives," "outlook," "intend," "plan," "predict," "project," "seek," "target," "begin," "could," "may," "should" or "would" or other similar expressions that convey the uncertainty of future events or outcomes. In accordance with "safe harbor" provisions of the Private Securities Litigation Reform Act of 1995, these statements are accompanied by cautionary language identifying important factors, though not necessarily all such factors, which could cause future outcomes to differ materially from those set forth in forward-looking statements. In particular, expressed or implied statements concerning future actions, the effects of Hurricane Ida or other storms, any potential damage to facilities caused by such storms, any potential impacts to the business caused by such storms, any financial impacts caused by such storms and related damage or shut-downs, and the availability of insurance to cover any damage or loss of income are forward-looking statements. Forward-looking statements are not guarantees of performance. They involve risks, uncertainties and assumptions. Future actions, conditions or events and future results of operations may differ materially from those expressed in these forward-looking statements. Forward-looking statements speak only as of the date of this press release, September 2, 2021, and we disclaim any obligation to update publicly or to revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law. All forward-looking statements contained in this document are expressly qualified in their entirety by the cautionary statements contained or referred to in this paragraph. Many of the factors that will determine these results are beyond our ability to control or

predict. More information on these risks and other potential factors that could affect the Partnership's financial results is included in the Partnership's filings with the U.S. Securities and Exchange Commission, including in the "Risk Factors" and "Management's Discussion and Analysis of Financial Condition and Results of Operations" sections of the Partnership's most recently filed periodic reports on Form 10-K and Form 10-Q and subsequent filings. If any of those risks occur, it could cause our actual results to differ materially from those contained in any forward-looking statement. Because of these risks and uncertainties, you should not place undue reliance on any forward-looking statement.

About Shell Midstream Partners, L.P.

Shell Midstream Partners, L.P., headquartered in Houston, Texas, owns, operates, develops and acquires pipelines and other midstream and logistics assets. The Partnership's assets include interests in entities that own (a) crude oil and refined products pipelines and terminals that serve as key infrastructure to transport onshore and offshore crude oil production to Gulf Coast and Midwest refining markets and deliver refined products from those markets to major demand centers and (b) storage tanks and financing receivables that are secured by pipelines, storage tanks, docks, truck and rail racks and other infrastructure used to stage and transport intermediate and finished products. The Partnership's assets also include interests in entities that own natural gas and refinery gas pipelines that transport offshore natural gas to market hubs and deliver refinery gas from refineries and plants to chemical sites along the Gulf Coast.

Inquiries:

Shell Media Relations

Americas: [phone]

Shell Investor Relations

North America: [phone]

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