Controversy dogs the Algonquin Incremental Market Project nearly six months after construction began. On Sept. 1, the Federal Energy Regulatory Commission approved the start of construction on the portion of the natural-gas pipeline near the Indian Point Energy Center, a 2000-MW, two-unit nuclear powerplant 35 miles north of New York City. But a variety of opponents are asking the Nuclear Regulatory Commission to order a construction halt on that part of the line.