A lawyer for Hyperion Resources says the company's proposed $10 billion oil refinery in southeastern South Dakota will be a clean, modern plant that helps the nation reduce its dependence on oil from overseas.

Rick Addison, a lawyer from Dallas, says the proposed refinery also will boost the economy in the area.  But a lawyer for project opponents says the state Board of Minerals and Environment should refuse to grant Hyperion an air quality permit because the proposed refinery would emit an unacceptable level of pollution into the air.

The board will hear evidence over a number of days in the next month or so.