Embattled BP has been slapped with a record fine for its Texas City explosion five years ago. 

The FTSE 100-listed major has agreed to pay the largest ever penalty of $50.6 million for failing to correct safety hazards in the wake of the 2005 explosion which killed 15 people. 

In a statement, the US Occupational Safety and Health Administration (OSHA) said the hefty figure 'rightly reflects BP's disregard for workplace safety'.

The Texas City Refinery disaster occurred when a container was over-filled with explosive chemicals which ignited a spark across nearby trailers.

The British oil major agreed to pay $21.3 million back in 2005 and struck a four-year agreement to enhance worker safety.

However, in October 2009 the OSHA found BP guilty of failing to correct 270 violations and issued the company with a $87.4 million fine in two parts. The first part consisting of $56.7 million was later reduced to $50.6 million, which BP has agreed to pay for the violations.

Steve Cornell, head of BP's US Refining business, issued a statement: 'This agreement demonstrates BP's commitment to work with OSHA in order to enhance safety performance at Texas City.

'We have significantly improved the safety of our operations at Texas City over the last five years and determined to carry this effort forward effectively in the future.'

The outstanding $30 million - for over 400'new wilful violations' - is still being contested by the company.

BP has also agreed to invest $500 million in safety and infrastructure improvements at the refinery - the third largest in the US - over the period 2010 to 2016.

Secretary of Labour Hilda Solis comments: 'This agreement achieves our goal of protecting workers at the refinery and ensuring that critical safety upgrades are made as quickly as possible.'

However, the figure pales into insignificance compared to its Gulf of Mexico oil spill, of which the clean-up costs have already surpassed the $6 billion mark.

The company is currently on the verge of intercepting the stricken Macondo well through a relief well which will mark the final stage in its efforts to permanently plug the well.

On Thursday, coast guard Admiral Thad Allen said that the final 'bottom kill' operation may not even be required if cement that was used during the 'static kill' effort at the top of the well has managed to plug the space between the inner piping and outer casing.

Officials are expected to know more today, once a test analysis has been carried out.

Shares in the group rose marginally to 410.48p.