West Texas Intermediate oil futures added to losses on Thursday, after data showed that manufacturing activity in the Chicago-area expanded at a much slower rate than expected in July. On the New York Mercantile Exchange, crude oil for delivery in September hit a session low of $99.10 a barrel, the weakest level since July 15, before trimming losses to last trade at $99.36 during U.S. morning hours, down 0.91%, or 91 cents. U.S. oil futures ended Wednesday’s session down 0.69%, or 70 cents, to settle at $100.27 a barrel. Nymex oil prices were likely to find support at $98.68, the low from July 15 and resistance at $101.67, the high from July 30. Market research group Kingsbury International said earlier that its Chicago purchasing managers’ index fell by 10.0 points to 52.6 in July from a reading of 62.6 in June. Analysts had expected the index to decline to 63.0 in July. It was the biggest monthly fall since October 2008 and left the barometer at its lowest level since June 2013. The disappointing data came after the U.S. Department of Labor said that the number of individuals filing for initial jobless benefits increased by 23,000 last week to 302,000 from the previous week’s total of 279,000, which was the lowest in 14 years. Also Thursday, data showed that the U.S. employment cost index rose at the fastest rate since September 2008 in the second quarter. Investors now turned their attention to Friday’s U.S. jobs report for July, which was expected to indicate that the recovery in the labor market is continuing. Elsewhere, on the ICE Futures Exchange in London, Brent oil for September delivery slumped 0.34%, or 36 cents, to trade at $106.15 a barrel.