Residents near a Tokyo Electric Power Co. nuclear reactor were ordered to evacuate because of a possible radiation leak as Japan’s strongest earthquake in a century shut power plants and oil refineries.

About 1,800 residents living within 1.2 miles of the Fukushima Dai-Ichi No. 1 reactor were ordered to evacuate, said Ryohei Shiomi, spokesman at the Emergency Information Center of the Nuclear and Industrial Safety Agency. Residents within 12 miles were told to stay indoors.

Firefighters continued to battle a blaze at Cosmo Oil Co.’s refinery, 40 kilometers east of Tokyo, said Seiichi Aso, a spokesman at the local fire department. The blaze started at the 220,000 barrel-a-day plant’s storage tanks, Cosmo Oil spokesman Yusuke Kaneda said. JX Nippon Oil & Energy Corp. said it shut its refineries in Sendai, Kashima, and Negishi.

Millions of homes were without electricity as utilities shut 11 nuclear power reactors. The shutdowns amount to about 20 percent of Japan’s 4.6 million barrels a day refining capacity and about 20 percent, or 12 gigawatts, of Japan’s total installed nuclear capacity, Sanford C. Bernstein analysts including Neil Beveridge said in a note today.

Reactors operated by Tokyo Electric Power Co., Asia’s biggest utility, Tohoku Electric Power Co. and Japan Atomic Power Co. were shut, the trade ministry said in an e-mailed statement. A fire broke out at a turbine building at Tohoku Electric’s Onagawa reactor, company spokesman Kazuya Sugawara said, adding that there’s no risk of a radiation leak.

Tokyo Electric shut seven reactors at its Fukushima Daiichi and Daini atomic plants while three reactors at Tohoku Electric’s Onagawa station were halted, the trade ministry’s Nuclear and Industrial Safety Agency said in the e-mailed statement. Japan Atomic Power shut the No. 2 reactor at its Tokai plant, the agency said.

More than 3.4 million homes serviced by Tokyo Electric were without power following the quake, Daisuke Hirose, a spokesman for the utility, said today by phone.

Electric Power Development Co. shut its 600-megawatt No. 2 unit of Isogo coal-fired plant in Yokohama, spokesman Hiroshi Nakatani said by telephone.

Tokyo Electric’s Kashiwazaki Kariwa, Chubu Electric Power Co.’s Hamaoka and Hokkaido Electric Power Co.’s Tomari nuclear plants are operating, the agency said.

Showa Shell Sekiyu KK said it halted shipments at refineries in Keihin and Yokkaichi. Liquefied natural gas import facilities at Sodegaura, Ohgishima and Negishi weren’t affected by the earthquake, Atsuhiko Ashikawa, a spokesman for Tokyo Gas Co. said today.

Officials at ports and energy companies in China, Taiwan, South Korea, and Russia said the quake and tsunami aren’t expected to affect operations.

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