MANILA, Philippines—For the second time this week, local oil firms slashed prices of gasoline, diesel and kerosene by P1 per liter starting midnight Friday night as crude prices plunged below $49 per barrel.

Pilipinas Shell Petroleum Corp. and Petron Corp. implemented the price cut at 12:01 a.m. Saturday while other local firms are expected to follow suit.

Just last Tuesday, the LPG Marketers Association slashed its prices by P2 per kilogram or P22 per 11-kg cylinder of liquefied petroleum gas.

The price cuts brought prevailing pump rates in Metro Manila of unleaded gasoline to a range of P36.07 to P41.51 a liter, diesel to between P34.97 and P38.17 a liter, and kerosene to between P41.80 and P47.49 a liter.

Oil prices fell to their lowest level in more than three years, dropping below $50 a barrel on Thursday (Friday in Manila), after shedding close to $100 since July as an ailing global economy cut back consumption.

Just as an economic boom had driven up commodity prices for six years, the present slowdown means the world needs less oil, which is depressing prices. Thursday’s drop came as a spate of new indicators showed how badly the economy was faring amid fears about the health of the financial system.