pollutants discharged to waters of the united states and remediation of waters affected by such discharge . to our knowledge , we are in compliance with all material requirements associated with the various regulations . the united states congress is actively considering legislation to reduce emissions of greenhouse gases , including carbon dioxide and methane . in addition , state and regional initiatives to regulate greenhouse gas emissions are underway . we are monitoring federal and state legislation to assess the potential impact on our operations . our most recent calculation of direct greenhouse gas emissions for oneok and oneok partners is estimated to be less than 6 million metric tons of carbon dioxide equivalents on an annual basis . we will continue efforts to quantify our direct greenhouse gas emissions and will report such emissions as required by any mandatory reporting rule , including the rules anticipated to be issued by the epa in mid-2009 . superfund - the comprehensive environmental response , compensation and liability act , also known as cercla or superfund , imposes liability , without regard to fault or the legality of the original act , on certain classes of persons who contributed to the release of a hazardous substance into the environment . these persons include the owner or operator of a facility where the release occurred and companies that disposed or arranged for the disposal of the hazardous substances found at the facility . under cercla , these persons may be liable for the costs of cleaning up the hazardous substances released into the environment , damages to natural resources and the costs of certain health studies . chemical site security - the united states department of homeland security ( homeland security ) released an interim rule in april 2007 that requires companies to provide reports on sites where certain chemicals , including many hydrocarbon products , are stored . we completed the homeland security assessments and our facilities were subsequently assigned to one of four risk-based tiers ranging from high ( tier 1 ) to low ( tier 4 ) risk , or not tiered at all due to low risk . a majority of our facilities were not tiered . we are waiting for homeland security 2019s analysis to determine if any of the tiered facilities will require site security plans and possible physical security enhancements . climate change - our environmental and climate change strategy focuses on taking steps to minimize the impact of our operations on the environment . these strategies include : ( i ) developing and maintaining an accurate greenhouse gas emissions inventory , according to rules anticipated to be issued by the epa in mid-2009 ; ( ii ) improving the efficiency of our various pipelines , natural gas processing facilities and natural gas liquids fractionation facilities ; ( iii ) following developing technologies for emission control ; ( iv ) following developing technologies to capture carbon dioxide to keep it from reaching the atmosphere ; and ( v ) analyzing options for future energy investment . currently , certain subsidiaries of oneok partners participate in the processing and transmission sectors and ldcs in our distribution segment participate in the distribution sector of the epa 2019s natural gas star program to voluntarily reduce methane emissions . a subsidiary in our oneok partners 2019 segment was honored in 2008 as the 201cnatural gas star gathering and processing partner of the year 201d for its efforts to positively address environmental issues through voluntary implementation of emission-reduction opportunities . in addition , we continue to focus on maintaining low rates of lost-and- unaccounted-for methane gas through expanded implementation of best practices to limit the release of methane during pipeline and facility maintenance and operations . our most recent calculation of our annual lost-and-unaccounted-for natural gas , for all of our business operations , is less than 1 percent of total throughput . employees we employed 4742 people at january 31 , 2009 , including 739 people employed by kansas gas service , who were subject to collective bargaining contracts . the following table sets forth our contracts with collective bargaining units at january 31 , employees contract expires .
as of january 31 , 2009 what percentage of employees are members of international brotherhood of electrical workers?
.