Meaning of 'force majeure'

[Tan Elaine]

Oil major Shell has declared force majeure on some customers, following a fire that forced the closure of its 500,000 barrels-per-day refinery in Singapore, a senior executive said on Sunday. (A few days ago, a fire broke out at the Shell refinery in Pulau Bukom. The fire took about two days to put out.)

What does the phrase in bold mean in relation to the text?

Thanks.

[5jj]

Shell are saying that they cannot be held liable for failure to fulfil contracts, because nobody can be held responsible for an 'Act of God'.

Force majeure - Wikipedia, the free encyclopedia