Is the polyethylene dragon rising from its slumber? After months of inactivity, North American PE makers have announced attempts to raise prices by 3 cents per pound effective Sept. 1. Their actions are being spurred by tightness in supplies of ethylene feedstock caused by unplanned outages at several plants, including those operated by Dow Chemical Co., LyondellBasell Industries and Chevron Phillips Chemical Co. North American prices for PE - the world's largest commodity resin - hadn't changed since a 4 cent hike took hold in February. The market has been in a historic period of low volatility, with only five price movements - all increases - taking hold since January 2013. By comparison, the North American PE market averaged seven price changes per year in the decade from 2003-2012, according to the Plastics News resin pricing chart. Midland, Mich.-based Dow had announced a 4-cent hike for Sept. 1, but all other producers announced 3-cent moves, leading market watc