John Rather

When several major oil companies agreed earlier this month to pay nearly $424 million to settle a federal lawsuit brought by scores of water providers claiming damages from the gasoline additive M.T.B.E., one Long Island provider took the largest share by far.

The Suffolk County Water Authority in Oakdale, which supplies water to more than 1.1 million customers in the county, walked away with $73.4 million of the settlement. That figure was by far the highest among the Long Island providers and the other more than 150 water companies from 17 states.

Tucked away in the woods off a winding side road here, the Lawrence Aviation Industries plant has kept a very low profile since it was established in the 1950's. All that most locals ever saw of the place was the gate and guardhouse just beyond a private railroad crossing along Sheep Pasture Road.

And no wonder: Lawrence Aviation made titanium parts for advanced military aircraft like the Grumman F-14 fighter jet.

Environmental officials say that it also made a terrible mess.

A GASOLINE additive intended to reduce air pollution, in large-scale use on Long Island for less than 10 years, is rapidly moving though the region's groundwater, penetrating drinking water supplies.

The additive, M.T.B.E., for methyl tertiary butane ether, has been found in the highest concentrations in shallow wells near gas stations and industrial areas where petroleum spilled. It is also being detected in nearly one in five of the deeper public wells that are the Island's principal sources of drinking water.