Tokyo ? Workers used a milky bathwater dye Monday as they frantically tried to trace the path of radioactive water seeping into the ocean from Japan’s tsunami-damaged nuclear plant.

The crack in a maintenance pit discovered over the weekend was the latest confirmation that radioactivity continues to spill into the environment. The leak is a symptom of the primary difficulty at the Fukushima Dai-ichi complex: Radioactive water is pooling around the plant and preventing workers from powering up cooling systems needed to stabilize dangerously vulnerable fuel rods.

The plant operators also deliberately dumped 10,000 tons of tainted water — measuring about 500 times above the legal limit for radioactivity — into the ocean Monday to make space at a storage site for water that is even more highly radioactive.

Engineers have turned to a host of improvised and sometimes bizarre methods to tame the nuclear plant after it was crippled in Japan’s magnitude 9.0 quake and tsunami on March 11.

Efforts over the weekend to clog the leak with a special polymer, sawdust and even shredded newspapers failed to halt the flow at a cracked concrete maintenance pit near the shoreline. They still can’t say for sure if the pit, where radioactive iodine was measured at 10,000 times the legal limit, is the source of the leak.

Suspecting they might be targeting the wrong channel to the pit, workers tried to confirm the leak’s pathway by dumping several pounds of salts used to give bathwater a milky hue into the system, plant operator Tokyo Electric Power Co. said Monday.

“There could be other possible passages that the water may be traveling. We must watch carefully and contain it as quickly as possible,” said Hidehiko Nishiyama, a spokesman for the Nuclear Safety and Industrial Agency.