story correct ninth paragraph say refiners want export ethanol qualify renewable credit export fuel blend ethanol david shepardson jarrett renshaw washington u.s. president donald trump seek ease concern wednesday administration would make major alterations biofuels policy tell iowa governor commit decade-old biofuels program even top official consider change u.s. law require fuel company add biofuels like ethanol country fuel supply renewable fuel standard adopt 2005. trump administration consider low mandatory level worry corn-growing state like iowa iowa governor kim reynolds say hold separate call trump u.s. environmental protection agency epa administrator scott pruitt wednesday urge make change personally commit continue commitment renewable fuel standard reynolds say add call trump positive however white house spokeswoman sarah sanders say administration make assurances renewable fuel standard rfs level definitive decision make rfs say biofuels industry ratchet pressure washington response action epa see threaten program design reduce carbon emissions independent oil refiners meanwhile push trump administration soften requirements ethanol use cost hundreds millions dollars annually refiners want another change would ease cost burden want export ethanol qualify credit renewable fuel program chief executives four company valero pbf energy monroe energy hollyfrontier deliver letter white house wednesday urge change two industry source tell reuters receive assurances white house officials trump direct epa allow credit export end efforts reduce renewable fuel requirements overall last month epa say look cut 2018 biodiesel blend requirements roil market draw criticism country farm belt july propose cut total volumes renewable fuel use next year elect officials corn-growing midwest say satisfy white house reassurances epa publicly agree reduce renewable fuel standards several senators meet pruitt tuesday discuss issue statement meet iowa republican senator joni ernst say express significant concern agency recent move potentially set biodiesel requirements 2018 2019 substantially low volumes senator charles grassley iowa republican say tell pruitt hour-long meet support biofuels good policy also president trump promise reynolds meanwhile urge iowans contact lawmakers administration officials say meet next week u.s. vice president mike pence pruitt washington group 33 senators write trump week urge epa maintain level 2018 increase propose 2019 biodiesel requirements pruitt would want take step undermine objectives statute rfs say epa spokeswoman liz bowman late tuesday senate committee environment public work postpone plan hear wednesday consider nominations four epa officials senator tammy duckworth illinois democrat say place hold two epa nominees ethanol issue ernst say wednesday decline support one nominees concern epa plan renewable fuel trump 'committed u.s. renewable fuel iowa governor