03/17/2012 04:04 pm ET Updated May 17, 2012

Brazil Navy: Oil Stain Spotted In Chevron Field

* Company filed this week to halt production at field

* Spill last year led to $11 billion civil suit

March 17 (Reuters) - The Brazilian navy said it spotted a thin stain of oil extending for about half a mile (1 km) in the same offshore field operated by U.S. oil company Chevron where a high-profile spill occurred last November.

Navy staff found the stain on Friday after flying over the area off Brazil's Atlantic coast, according to a statement late on Friday. The navy, oil industry regulator ANP and environmental protection agency Ibama will monitor and coordinate actions with Chevron to control the stain, the statement added.

Chevron filed to halt production operations temporarily in Brazil on Thursday after it detected a "small new seep" of oil in the Frade field.

The company said it was taking the step as a precautionary measure to study its "reservoir management plans" in Brazil, where it has spent over $2 billion developing the largest foreign-run oil field. If approved by Brazilian regulators, the suspension will shut down a field with the capacity to produce 80,000 barrels a day, more than 3 percent of Brazil's oil output.

A Rio de Janeiro-based public relations executive for Chevron said the company did not have an immediate comment on the navy statement.

Chevron's previous spill in November leaked as many as 3,000 barrels from sea-floor cracks. It resulted in an $11 billion civil lawsuit, the largest environmental damages case in Brazil's history, although the total amount of oil was less than 0.1 percent of the BP spill in 2010 in the Gulf of Mexico.

Chevron said on Thursday there was no evidence yet the two spills were related.

ANP, Brazil's navy and Ibama officials will meet early next week to assess the situation, the statement added.