Canadian manufacturers had a notable pull-back in sales in August following four consecutive monthly increases.

Sales decreased 3.7% to $52.0 billion, erasing most of the gains from the previous two months, Statistics Canada reported today.

StatsCan said the biggest factor in the drop was the petroleum and coal products industry, where sales have fallen by nearly $1 billion in two months.

The drop in the petroleum and coal sector was due to falling prices — which were off by 5.9% — coupled with unplanned production slowdowns at two major plants.

Petroleum and coal product sales fell 7.7% in August, decreasing by over $600 million.

The drop, however, was not limited to petroleum and coal, as 18 of the 21 manufacturing industries, accounting for 96% of Canada’s total manufacturing sales, reporting declines.