The imminent prospect of a three-fold increase in the volume of oil passing through the Turkish straits has heightened concerns in Turkey about the wisdom of shipping so much hazardous liquid through the center of Istanbul, a city of 15 million people. The newly completed pipeline linking Kazakhstan's Tengiz oilfields with the Russian Black Sea port of Novorossisk began pumping oil at the end of March, and the first tankers are due to make their way through the straits as early as June. But the environmental and safety issues are caught up in a wider debate about the geopolitics of Caspian oil.

The dangers to shipping posed by the Bosphorus, as it snakes its way through Istanbul, linking the Black Sea with the Sea of Marmara, even found their way into classical mythology. According to legend, Jason and the Argonauts were forced to negotiate the lethal 'Clashing Rocks' at the mouth of the strait. Today the Bosphorus is still one of the trickiest -- and busiest -- navigable waterways in the world.

To try and publicize the dangers, the Turkish environmentalist group 'Peace With Nature' has publicized a "nightmare" scenario, in which a collision between tankers in mid passage turns the Istanbul strait into a river of fire that engulfs the city, causing massive loss of life and destroying historic monuments.

"That's not so far-fetched," says the group's Yuksel Ustun, recalling the Nassia disaster in 1994, when a Cypriot-registered tanker collided with a freighter, drifted and foundered ashore -- not far, ironically, from the mythical site of the 'Clashing Rocks' at the Black Sea entrance to the strait. The Nassia's cargo of 19 million gallons of crude oil burned for a week, and 28 sailors were killed. If the accident had occurred just a few hundred meters further downstream, the currents would have carried the burning ship straight into the center of the city.

Despite the potential hazard, Ustun's appeal to the residents of Istanbul to physically stop the tanker traffic if necessary is unlikely to elicit more than a token response. Most Turks are too preoccupied with the effects of an economic crisis, and civil protest on environmental issues is still in its infancy.

Neither is the government in a position to do much, even if it wanted to, since the 1936 Montreux Convention explicitly guarantees the free passage of shipping through the Turkish straits. Critics point out that when the treaty was drawn up, an average of 17 ships a day passed through the Bosphorus, and supertankers did not even exist. The Turkish Maritime Pilots Association calculates that nearly 5,000 tankers completed the passage last year, over 2,000 of them longer than 200 meters.

Shipping Minister Ramazan Mirzaoglu has said, however, that Turkey could invoke concessions wrested from the International Maritime Organization (IMO) in 1994 to try to regulate a rise in shipping traffic arising from Kazakh oil, perhaps by staggering the number of passages. Better piloting procedures and a new radar tracking system are also due to be introduced shortly. "The Turkish straits are at the saturation point," Mirzaoglu warned at the end of March, foreseeing gridlock if the Kazakh oil is shipped to international markets by sea.

That statement dismayed Russia, which has accused Turkey of trying to block the maritime shipment of Kazakh oil in a bid to promote the alternative Baku-Ceyhan pipeline project. Experts detect an element of truth in that assessment, as far as it goes. "Turkey may benefit from alternative pipelines being built," said an oil industry analyst, "but it has no need to exaggerate the dangers of a shipping disaster in Istanbul. They are plain for all to see."

Nevertheless, Russian influence over the future of Caspian oil has never been greater. As Tengiz-Novorossisk looks set to flourish and Baku-Ceyhan continues to flounder, tensions between Turkey and Russia, and possibly even Kazakhstan, could mount. Turkish politicians would do well to remember that at the summit of Turkic-speaking nations, held at the Ciragan Palace on the Bosphorus at the end of April, the lingua franca was not Turkish, but Russian.