Vehicles line up to refuel as a gas station reopens for business today in northeastern Japan. Radiation fears in the country are prompting panic buying by shoppers.

TOKYO — Some shops across Tokyo began rationing goods — milk, toilet paper, rice and water — as a run on bottled water coupled with delivery disruptions left shelves bare today nearly two weeks after a devastating earthquake and tsunami.

The unusual sights of scarcity in one of the world's richest, most modern capitals came a day after city officials reported that radioactive iodine in Tokyo's tap water measured more than twice the level considered safe for babies.

Radiation has been leaking from a nuclear plant 140 miles northeast of Tokyo since it was slammed by the March 11 quake and engulfed by the ensuing tsunami. Feverish efforts to get the plant's crucial cooling system back in operation have been beset by explosions, fires and radiation scares.

Today, two workers at the Fukushima Dai-ichi plant were treated at a hospital after stepping in contaminated water while laying electrical cables in one unit, nuclear and government officials said. The water seeped over the top of their boots and onto their legs, said Takashi Kurita, spokesman for plant owner Tokyo Electric Power.

The two workers likely suffered “beta ray burns,” Tokyo Electric officials said, citing doctors. They tested at radiation levels between 170 to 180 millisieverts, well below the maximum 250 millisieverts allowed for workers, said Fumio Matsuda, a spokesman for the Nuclear and Industrial Safety Agency.

More than two dozen people have been injured trying to bring the plant under control.

The developments highlighted the challenges Japan faces after a magnitude-9.0 quake off Sendai triggered a massive tsunami. An estimated 18,000 people have been killed and hundreds of thousands have been left homeless as officials scramble to avert a major nuclear crisis.

Radiation has seeped into raw milk, seawater and 11 kinds of vegetables, including broccoli, cauliflower and turnips, grown in areas around the plant.

The U.S. and Australia were halting imports of Japanese dairy and produce from the region, Hong Kong said it would require that Japan perform safety checks on meat, eggs and seafood, and Canada said it would upgrade controls on imports of Japanese food products.

Concerns spread to Europe. In Iceland, officials said they measured trace amounts of radioactive iodine in the air but assured residents it was “less than a millionth” of levels found in European countries in the wake of the 1986 Chernobyl disaster.In Tokyo, government spokesman Yukio Edano pleaded for calm, and said the government was considering importing bottled water from other countries to cover any shortages. Officials urged residents to avoid panicked stockpiling, sending workers to distribute 240,000 bottles — enough for three small bottles of water for each of the 80,000 babies under age 1 registered with the city.

A man walks today along streets in the devastated city of Ishinomaki in northeastern Japan. The earthquake and tsunami have left an estimated 18,000 people dead and hundreds of thousands homeless.