Environment : A Strait of Trouble : More than 1,300 ships use the narrow Bosporus strait each day. Some of those are oil tankers. And that has plenty of people worried.

Accidents happen.

One recent night it was an Egyptian freighter whose bow carved into the coast road. Last year it was a ship that sank with a load of 17,000 sheep, whose ghostly, bloated carcasses floated up to the surface for months.

But it is the prospect of tankers shipping out millions of tons of crude oil pumped from fields under development in Russia and Central Asia that really frightens shipowners and officials involved with the 1,350 ships per day that use the Bosporus strait.

“All over the world they are discussing how many miles oil tankers should be kept away from uninhabited coastlines,” said Altan Koseoglu, the Turkish official who supervises the waterway running through this city of 10 million people. “Here we are talking about 50 meters. It makes me very worried, and the risk is rising every day.”

As traffic chokes the strait, mishaps multiply. In 1988, there were 11 ship accidents in the strait; in 1991, there were 56, Koseoglu said. A few have involved tankers, and now several million barrels of oil are passing through the strait each year.

One evening in November, 1979, Istanbul had a taste of a real environmental catastrophe along the 20-mile-long strait: A Greek freighter collided with the Romanian oil tanker Independenta, triggering an explosion. The tanker sank in a lake of burning crude oil that sent a heavy pall of thick, black smoke billowing up over the city.

“The blast was heard all over Istanbul. It burned for days and the smoke came out for weeks,” said Sami Kohen, a veteran commentator for the daily newspaper Milliyet. “The wreckage was there for years.”

Citing fears that the Independenta disaster could easily happen again, Turkish officials made known at a special briefing this month that Turkey will not tolerate the growth of oil tanker traffic and may be forced to introduce some kind of quota system for the congested shipping lane.

Such a move could threaten the right of ships of all flags and cargoes to pass through the Turkish strait with no restrictions, as guaranteed in the Montreux Convention of 1936 and a century of international treaties. Particularly affected would be Russia, which uses the strait for access to the Mediterranean.

The Bosporus, along with the Dardanelles strait, helps link the Black Sea to the Mediterranean via the Sea of Marmara and the Aegean Sea. Russia, Ukraine, Bulgaria, Romania and Georgia rely on the strait as a regional route for all seagoing shipping trade. Increasing use of the Volga-Don and Danube-Rhine river systems brings connections to Azerbaijan, Kazakhstan, Turkmenistan and many countries in the Balkans and Central Europe.

Back in the 1930s only a few foreign-flag ships a month passed through the strait. Now, about 60 a day go through. “We are getting close to the maximum traffic possible,” Koseoglu said. The proportion of oil traffic is already rising on a waterway that is just 700 yards wide at its narrowest point and where swirling, unpredictable currents can reach seven miles an hour, Turkish officials say.

“It is not possible for large amounts of oil to pass. . . . We don’t want to raise Montreux. But we are not afraid to challenge it,” said Tevfik Okyayuz, a senior Foreign Ministry official.

If no action is taken, Turkey claims, there could be an annual 150 million tons of Russian, Kazakh and Azerbaijani oil shipped out of the Black Sea and throughthe Bosporus within 10 years. The amount is rising due to the arrival of Western oil companies eager to exploit new concessions in the former Soviet Union, and the need of the former Soviet republics to sell oil for hard cash.

At an annual volume of 150 million tons, Turkey says, the oil would fill about 1,200 super-tankers, which, because each supertanker blocks the Bosporus for six hours, could close off the strait for 300 days a year.

Still, the new oil consortiums are in their infancy, and only one to five supertankers actually use the strait each year. Critics accuse Turkey of raising the issue in an attempt to influence politically charged proposals to build oil pipelines across the Caucasus and Central Asia.

Negotiations on the pipeline routes have been pursued in the Azerbaijani capital of Baku and London this month and were being resumed this week in the Turkish capital of Ankara.

Several routes, all of which would bypass the strait and thus remove the dangers of oil tankers, have been proposed.

One might lead from the Tengiz oil field, under development by Chevron in Kazakhstan, go across the Caspian Sea and through Baku and then connect to an existing Turkish pipeline that ends at the Mediterranean. Another one might lead from Baku, either through Georgia or via the Aras river valley through Armenia. An alternate route would take the oil from Baku through Iran and end at the Persian Gulf. The current pipeline from Tengiz goes to Novorossiysk, Russia, on the Black Sea, where the oil is loaded onto ships that pass through the strait. One plan would simply build up that pipeline.

Azerbaijan holds the key, since the contract for its $1.5-billion, 900-mile-long pipeline is closest to signing. After undergoing a coup in June, Azerbaijan has insisted on renegotiating key areas of the extraction and pipeline contracts. Companies in that consortium include British Petroleum/Statoil, Amoco, Pennzoil, Unocal, MacDermott and the Turkish state oil company.

Turkey favors the route through the Caucasus via Georgia to its big oil terminal at Yumurtalik in the Mediterranean bay of Iskenderun. It is suspicious of routes that must pass through Iran and is using the Bosporus environmental argument against the use of any Black Sea port, including Novorossiysk.

Russia worries about any Turkish action in the strait that could reduce its access to the Mediterranean, for which Moscow has fought and negotiated for centuries.

It appears to favor, for an interim period at least, increased traffic through the strait by small oil tankers.

“We should not allow any one country to have a monopoly on the region . . . control of the pipe valve,” said Albert Chernishev, Russia’s ambassador to Turkey. In a Turkish newspaper interview, he cited southern Russia’s limited access to warm-water ports.

Russian diplomats also point out that there is currently fighting or instability on all trans-Caucasus routes, including areas in Turkey where Kurdish guerrillas are active.

Turkish officials counter that storms make loading impossible for 165 days a year at the shallow Novorossiysk port, where some in Russia are proposing to expand existing oil facilities. Storms disrupt Yumurtalik’s deep-quay loading only one day a year.

“There are also about $1 billion in transit fees at stake. That is why we are offering incentives. Nobody gives anything for free,” said Okyayuz of the Turkish Foreign Ministry. “But there’s a wrong image. Turkey is pushing the pipelines to save the Bosporus, not the Bosporus just to get pipelines.”