To meet society's current and future energy needs, MPC must do our part as responsible stewards of the environment we all share. We are committed to minimizing our environmental impact and reducing our footprint through advanced practices and investments to protect biodiversity, reduce waste, reduce freshwater withdrawal and improve air quality.
MPC employs multiple proactive measures to protect plant and animal species and preserve their natural habitats. Our Operational Excellence Management System provides the procedural framework to ensure we account for the potential effects of our activities on ecosystems and prepare necessary mitigation procedures. Our approach also involves ongoing collaboration with applicable state and federal regulatory agencies, including the U.S. EPA, U.S. Fish and Wildlife Service, U.S. Bureau of Land Management and U.S. Army Corps of Engineers.
We are continually working to reduce the volume of waste we generate and to find alternatives for disposal, such as energy recovery and recycling. Since 2013, approximately 95,800 tonnes of waste from our refineries has become an alternative fuel source for the cement industry, avoiding approximately 230,000 tonnes of CO2e emissions. We also work with companies that specialize in metals reclamation, in lieu of using landfills, to manage many of thes 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.
Reducing Freshwater Withdrawal
MPC strives to actively manage and monitor water use throughout all operations. Responsibly managing the use and sourcing of fresh water is especially critical in water-stressed regions in the U.S. We continually evaluate opportunities to reduce and manage our use of this shared resource, and to further our commitment to water conservation, we voluntarily set a companywide target to reduce freshwater withdrawal intensity by more than 20% by 2030 from 2016 levels.
Through a variety of innovations at our refineries, we have reduced our freshwater withdrawal intensity by over 9% since 2016 and have plans for additional reductions. We adopted a formal, refinery-wide “Focus on Water” program to further assess water use, understand and mitigate water risks and identify opportunities to reduce water use.
Improving Air Quality
We have a comprehensive approach to improving air quality that aims to lower emissions of criteria pollutants by producing cleaner fuels, reducing gas flaring and minimizing fugitive emissions. From 2002 to 2020, we reduced our criteria pollutants by 54 percent, while the footprint of our refining and natural gas assets expanded. We have invested over $1 billion to achieve these substantial results. We are also making ongoing improvements within our gathering and processing operations designed to further reduce fugitive emissions.
We are an industry leader in reducing emissions from refinery flares. Our flare reduction strategy focuses on source reduction (preventing gases from entering the flare system), waste gas recovery and optimizing flare combustion efficiency. The majority of our 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 emissions.