Should air contaminant emissions from large dairies be tracked and regulated in Oregon? A legislative task force concluded in July 2008 that they should.The Legislature didn't implement the recommendation, and dairy industry officials say voluntary actions are better than regulations. Buta proposal for a new mega-dairy in Eastern Oregon has prompted legislators to take a second look. A Senate committee will hold a public hearing Thursday on SB 197, which would require the Oregon Environmental Quality Commission to adopt a program for regulating air contaminants from dairy confined animal feeding operations. In Oregon, dairies and other confined animal feeding operations must obtain a National Pollutant Discharge Elimination System Permit, which details how manure will be stored and disposed of. There are no rules, however for air emissions.