It is Dow’s policy to adhere to a waste management hierarchy that minimizes the impact of waste and emissions on the environment. First, we work to eliminate or minimize the generation of waste and emissions at the source through research, process design, plant operations and maintenance. Second, we also find ways to reuse and recycle materials. Next, unusable or non-recyclable hazardous waste is treated before disposal to eliminate or reduce the hazardous nature and volume of the waste. Treatment may include destruction by chemical, physical, biological or thermal means. Disposal of waste materials in landfills is considered only after all other options have been thoroughly evaluated. Total waste disposed of in 2020 was 1.39 million metric tons.
In 2016, Dow began using a new metric, Process Safety Containment Event (PSCE). Our PSCE metric is derived from an industry best practice, API RP-754. As an industry leader in sustainability performance, we have been heavily involved in the development of this metric. We believe aligning to this measure will help us achieve an even higher level of performance related to the containment and control of the materials we handle and produce.
Similar to the approach we are now taking with injury and illness measurement, our PSCE metric focuses on both incidents that have the greatest impact, as well as incidents with the greatest potential for significant impact, including process damage, interruption or possible impact on our surrounding communities. We have defined Levels 1-4, with Level 1 incidents having the highest actual or potential impact. By 2025, our goal is to reduce the number of Level 1 and Level 2 events by more than 80% from our 2015 baseline.
In 2020, the company had 29 PSCEs, well below our target line for achieving our 2025 goals, but up from our 2019 performance. We will continue our focus on PSCE reduction, specifically targeting improvement in the quality and use of our operating discipline and in our mechanical integrity preservation management system implementation. We also will strive to continue to understand and prevent our near misses with the greatest potential for avoidance.