The Solidarity union claims its members at Sasol are striking over a share ownership scheme offered only to black staff.

A South African trade union with mainly white members went on strike on Monday at a petrochemical firm over a share ownership scheme offered exclusively to black employees.

The Solidarity Union, which has 6,300 members at Sasol’s South African operations, said the move by the firm is “blatant discrimination”.

“The Sasol employees who are members of Solidarity started officially today… the great expected strike,” the union said in a statement posted on their Facebook page on Monday.

The union, on Sunday, described the strike as “the first time in the history of South Africa that white employees strike because of racial exclusion”.

“We intend to switch off a different section of Sasol each day by means of well-laid and strategic plans,” the union said on Sunday.

Companies in South Africa are required by law to meet quotas on black ownership as part of a drive to reverse decades of exclusion under apartheid.

Sasol said last year it would raise its black ownership levels in Sasol South Africa to at least 25 percent in a $1.5bln deal. Sasol converts coal and gas to fuel.

The petrochemical firm, which has around 26,000 employees at its local operations, said it received notification from the trade union of its intent to strike on Monday and was open to engagement with the union.

“We have activated contingency measures to minimise potential disruption to our operations,” Sasol told Reuters news agency.