WALDSHUT, West Germany (AP) _ About 2.7 tons of a chemical leaked from a factory into the Rhine on Tuesday in the eighth industrial accident along the river in a month, officials said.

The leak of polyvinyl chloride (PVC), a substance used in food wrappers, came from the Lonza chemical factory in Waldshut, authorities said.

The spill was discovered Tuesday morning when a local resident noticed the Rhine turning shades of green and white downstream from the plant, Waldshut police said.

Environmental authorities in Baden-Wuerttemberg state alerted neighboring Switzerland and France.

Company spokesman Friedrich Schildknecht said the chemical poured into the Rhine with waste water after an employee mistakenly left a valve open. The substance will break down quickly in water, he said.

Lorenz Fischer, spokesman for the Baden-Wuerttemberg Environment Ministry in Stuttgart, told The Associated Press about 15 pounds of the leaked substance were in concentrated form and ''relatively poisonous.''

However, Fischer said the chemical was unlikely to endanger fish and plant life because it was lighter than water and would remain on the river's surface.

Waldshut sits on the Rhine where the river forms West Germany's border with Switzerland.

The town is about 36 miles upstream from Basel, Switzerland, where 30 tons of chemicals spilled into the Rhine on Nov. 1 from the Sandoz chemical company, contaminating long stretches of the Rhine.

The Swiss government said Tuesday it would tighten controls on the chemical industry and seek better international cooperation on environmental issues following the Sandoz spill.

Experts said none of the subsequent spills posed serious environmental threats, but the recent rash of accidents has led the West German government to consider stricter industrial safety measures.