The sale of the Decatur complex, which BP acquired in its 1998 merger with Amoco, is part of the company's refocused petrochemicals strategy, pursuing what it calls a "competitively advantaged portfolio" through world-scale, low-cost facilities that utilise its proprietary technology including the production of purified terephthalic acid, or PTA, a key raw material in the production of polyester and plastics.

"BP's world-leading technologies and global positions allow us to compete in today's highly competitive marketplace," BP's global downstream business CEO Tufan Erginbilgic said.

"Our strategy is to significantly improve the cash breakeven performance of the business, enhancing earnings potential and making it more resilient to bottom-of-cycle conditions.

BP is spending $US200 million ($A281.88 million) to upgrade its plant in Cooper River, South Carolina and its sister facility in Geel, Belgium - the largest PTA-producing sites in the Americas and Europe, respectively.

The investment will enable the two facilities to lower operating costs, improve reliability and reduce emissions.

Earlier this year, BP also started up its new Zhuhai 3 unit in China's Guangdong province.

Using the latest technology that is capable of producing up to 1.25 million tons per annum, Zhuhai 3 is the world's largest single-train PTA production unit, and one of the most efficient PTA production units in the world.

The Decatur complex, which BP indicated no longer fits with the company's new strategy, an produce 1MMtpa of PTA, as well as paraxylene, a raw material for PTA production.

The site also is the only commercial manufacturer of naphthalene dicarboxylate, a specialty chemical used in new-generation polyesters and resins used to make LCD flat-panel displays, ultra-thin data storage tape and other products.

Of the five operating units on the Decatur site, three produce PTA, one makes paraxylene and the other makes NDC.

"The decision to explore a sale of this facility was not taken lightly. It has been a significant part of our company and of the Decatur community for a very long time," BP global petrochemicals chief operating officer Rita Griffin said.

"We believe the site -- and its more than 400 employees -- would be a very attractive addition to the portfolio of another operator. We're determined to find a buyer who will recognise its value and keep it a viable and vibrant part of the region for years to come."