We Take Pride in Our Role as Environmental Stewards

Preserving Our Surroundings

MPC owns and maintains 23 wildlife habitats with more than 1,347 acres of land. From prairies and wetlands to locations where bees are kept, each habitat is unique and part of our long-term commitment to environmental stewardship.

Energy efficiency is central to our core values, but it goes beyond environmental sustainability. It's about our company's sustainability as a whole because it strengthens the bottom line.

a beautiful butterfly

Energy Efficiency

Energy efficiency is one of our key metrics with both environmental and financial benefits. By identifying where energy can be conserved cost-effectively, we reduce our operating costs, save our shareholders money and reduce our environmental footprint.

We have implemented multiple programs to improve energy efficiency across our assets including a Focus on Energy program within our refining organization. Through this program, we measure energy efficiency by using the HSB Solomon Associates Energy Intensity Index (EII®). According to the most recent Solomon study, released in 2019, five of our refineries were considered Top Tier, based on EII in their respective equivalent distillation capacity (EDC®) class.

As we implement the “Focus on Energy” program across the 10 additional refineries we acquired from Andeavor, we expect our EII scores will continue to improve. Our energy-efficiency programs and associated metrics have achieved best-in-class performance with numerous U.S. Environmental Protection Agency (EPA) certifications and endorsements through the ENERGY STAR® and SmartWay® Programs, including the ENERGY STAR Partner of the Year award in 2018 and 2019. We were the only oil and gas company to receive this honor in 2018 and 2019.

MPC is the industry leader in recognition under the ENERGY STAR Program, having earned 74 percent of the total recognitions (43 of 58).

View Our 2018 ENERGY STAR Video

Flare Reduction and Efficiency

We are an industry leader in reducing emissions from refinery flares.  As part of the EPA’s refinery flare enforcement initiative, we collaborated with the EPA to define operating parameters, such as Net Heating Value in the Combustion Zone (NHVcz), that ensure flares continuously operate above 98 percent combustion efficiency.  We were the first company to produce and publish the results of our own flare performance tests, which EPA acknowledged was a unique level of cooperation that is rarely seen. Subsequently, we entered into an agreement with the EPA to reduce flaring emissions at our refineries and incorporated the newly developed operating parameters. These same parameters were used by EPA to set regulatory standards for industrial flares throughout industry.


By working with EPA, Marathon helped advance new approaches that reduce air pollution and improve efficiency at its refineries and provide the U.S. with new knowledge to bring similar improvements in air quality to other communities across the nation.

– Cynthia Giles, Former Assistant Administrator for EPA's Office of Enforcement and Compliance Assurance, April 2012


Our flare reduction strategy focuses on source reduction (preventing gases from entering the flare system), waste gas recovery and optimizing flare combustion efficiency. Fourteen of our 16 refineries have flare gas recovery systems that recover gas entering the flare system, so it can be used as fuel within the refinery instead of being burned by the flare. Recovering these gases reduces reliance on purchased natural gas, lowering overall greenhouse gas (GHG) emissions. In total, our refineries have invested more than $500 million on projects that reduce flaring, increasing the value of the gas streams we now recover to more than $30 million per year. We estimate these improvements have resulted in a 90 percent reduction in emissions of volatile organic compounds, an 87 percent reduction in emissions of hazardous air pollutants, and a nearly 60 percent reduction in GHG emissions from flares compared to emissions prior to implementing the program.

Flare Gas Illiustration

Greenhouse Gas Emission Reductions 

We have reduced our greenhouse gas (GHG) intensity significantly since 2014 through our energy efficiency measures and the diversification of our portfolio. For instance, our Focus on Energy program has enabled us to increase refining capacity by nearly 250,000 barrels per day. In addition, our natural gas processing and fractionation facilities have lowered our company-wide GHG intensity since acquisition in late 2015. Overall, our energy efficiency efforts have avoided emitting millions of tons of GHGs per year. Learn more in our Perspectives on Climate-Related Scenarios publication.

View Greenhouse Gas Emissions Charts

Criteria Pollutant Emissions

Energy efficiency and flare reduction also aid MPC's work to reduce criteria pollutant emissions. The graphs below illustrate the success of these efforts. 

From 2002 to 2018, we reduced our criteria pollutants by 42 percent, more than 44,000 tons. Such reductions are not achieved without significant expense. We have invested over $1 billion to achieve these dramatic results. We are also making ongoing improvements within our gathering and processing operations designed to further reduce fugitive emissions.

  View Criteria Pollutant Emissions Charts

Reducing Methane Emissions

Through MPC's master limited partnership, MPLX LP, we operate one of the largest natural gas gathering and processing networks in the country. We are continually advancing opportunities to reduce emissions of methane and other pollutants.  Some key focus areas we are actively addressing include reducing emissions from pipeline launchers and receivers, lowering fugitive emissions from equipment, and replacing pneumatic controllers.      

  Read More

Waste Reduction and Recycling

We are continually working to reduce the volume of waste we generate and to find alternatives for disposal, such as reclamation and recycling. A recent example is the construction of a thermal desorption unit (TDU) at our Galveston Bay refinery. The new TDU will complement units already in operation at our Catlettsburg, Garyville and Robinson refineries. The thermal desorption process uses indirect heat to separate hydrocarbons from oily waste materials. This has three main benefits: (1) hydrocarbons are recovered and returned to the refining process as feedstock, (2) the hazardous characteristics of the waste materials are removed, and (3) the total volume of waste material is reduced. We also work with companies that specialize in metals reclamation, in lieu of using landfills, to manage many of the spent catalysts we use in our processes. These companies recover and recycle metals, such as cobalt, copper, molybdenum, platinum and vanadium. This reduces the overall volume of material to be landfilled and provides a beneficial use for these materials.