The massive Gulf of Mexico oil spill has prompted global investors responsible for $2.5 trillion in assets to pressure major oil and gas companies to reveal the prevention and response plans they have in place for any similar disaster.

Domestic and international investors from 58 firms sent letters to the CEOs of 27 oil and gas companies asking them to reveal their risk oversight measures for their offshore oil operations around the world.

Deepwater oil production has tripled since 2000 to five million barrels a day and has the potential to double again by 2015, according to Cambridge Energy Research Associates. There are now 14,000 deepwater wells, 2,000 feet or deeper, in the world.

"The shareholder harm that has flowed from the BP spill has focused investor attention on governance, compliance and management systems needed to minimize risks associated with deepwater offshore oil and gas development," the investors say in the letter.

The campaign is being organized by Ceres, a coalition of investors, environmental groups and public interest organizations. A letter did not go to BP, which has seen its stock plummet since the spill, but was sent to the three largest deepwater oil producers, Petrobras, ExxonMobil and Royal Dutch Shell, among others.

A letter also was directed to 26 insurance companies that provide insurance for offshore drilling activity. The letter asks if insurers are considering adjustments to their exposure to offshore oil and gas operations.

The letters to energy companies asks, among other things, what their spill contingency plans are and their position on possible new stiffer regulations and enforcement on offshore drilling. Companies are asked to replay by Nov. 1.