The best way to prevent pollution is to reduce the generation of waste at its source. This has been a basic philosophy behind IBM's pollution prevention program since 1971. Where possible, we redesign processes to eliminate or reduce chemical use or to replace chemicals with more environmentally preferable substitutes. We maintain programs for proper management of the chemicals used in our operations, from selection and purchase to storage, use and final disposal.
The total hazardous waste generated by IBM worldwide in 2015 decreased by 32 percent from 2014, to 2,740 metric tons. This reduction was primarily associated with the divestiture of IBM's semiconductor manufacturing operations in July 2015. Excluding hazardous waste from those operations, IBM would have seen a 0.2 percent reduction in the generation of hazardous waste in 2015.
For the hazardous waste that is generated, we focus on preventing pollution through a comprehensive, proactive waste management program. Of the total 2,740 metric tons of hazardous waste IBM generated worldwide in 2015, 58 percent was recycled, 25 percent was sent off-site for treatment, 10 percent was sent by IBM directly to regulated landfills and 7 percent was sent for incineration.
IBM has also focused for decades on preventing the generation of nonhazardous waste, and where this is not practical, recovering and recycling the materials that are generated. Nonhazardous waste includes paper, wood, metals, glass, plastics and other nonhazardous chemical substances.
We established our first voluntary goal to recycle nonhazardous waste streams in 1988. The goal has since evolved on two fronts. The first expanded on the traditional dry waste streams to include nonhazardous chemical waste and end-of-life IT equipment from our own operations, as well as IBM-owned equipment that is returned by external customers at the end of a lease. The second expansion was made to include nonhazardous waste generated by IBM at leased locations meeting designated criteria.
Our voluntary environmental goal is to send an average of 75 percent by weight of the nonhazardous waste generated at locations managed by IBM to be recycled. In 2015, we sent 85 percent of the nonhazardous waste generated by IBM worldwide to be recycled.
Treatment methods that are credited toward the waste recycling target included: reuse, recycle, energy recovery, composting, reclamation and land farming. Treatment methods that result in a non-beneficial use and that are not credited toward our recycling target included incineration, landfilling, and treatments such as aqueous treatment, biodegradation of organics, filtration, neutralization and stabilization.
In 2015, our worldwide operations generated approximately 53,000 metric tons of nonhazardous waste, a decrease of 54,000 metric tons from 2014. This significant reduction was largely due to a decrease in the generation of construction debris from construction projects as compared to 2014. In addition, the divestiture of IBM's semiconductor manufacturing operations in July 2015 resulted in further decreases in nonhazardous waste generation. Excluding construction debris and wastes associated with divested semiconductor manufacturing operations, IBM would have seen a reduction of 5,000 metric tons of nonhazardous waste generation in 2015.
Source reduction and waste prevention initiatives implemented by IBM worldwide were estimated to have prevented the generation of over 5,800 metric tons of nonhazardous waste in 2015, with estimated annual handling, treatment and disposal cost savings and revenue returns totaling $3 million.