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 radiactivity — into the ocean Monday to make space at a storage site for water that is even more highly radiactive.

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. The water in that leak contains radioactive iodine at rates 10,000 times the legal limit.

Suspecting they might be targeting the wrong channel to the pit, workers tried to confirm the leak's pathway by dumping several pounds (kilograms) 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.

Radioactive water has pooled throughout the plant because the operator has been forced to rely on makeshift ways of pumping water into the reactors β€” and allowing it to gush out wherever it can β€” to bring down temperatures and pressure in the cores.

Government officials conceded Sunday that it will likely be several months before the cooling systems are completely restored. And even after that happens, there will be years of work ahead to clean up the area around the complex and figure out what to do with it.

The makeshift system makes it difficult to contain the radiation leaks, but it is aimed a preventing fuel rods from going into a full meltdown that would release even more radiactivity into the environment.