UPDATE: Fire guts industrial complex in Sydney's west

A grass fire which spread to an industrial estate, sending billowing black smoke across Sydney's west, has been brought under control.

The fire started in some grass at the back of an industrial estate near Copeland Street, Kingswood, near Penrith.

Factories and multiple cars caught fire, with more than 80 firefighters on scene to fight the blaze.

Crews surrounded the burning 200sqm car factory on two sides but flames licked at other buildings and threatened a supply of gas cylinders.

There were 16 crews on scene in the windy conditions and water tankers were requested from the Rural Fire Service.

The two nearby schools were preparing for a possible evacuation.

The Facebook page of St Joseph's College indicated that students and staff were staying inside and closing windows and doors.

NSW Fire and Rescue’s Commissioner Greg Mullins said the huge blaze was concerning, coming so close to the fire season.

“I was watching this unfold on the dispatch system, it literally took minutes,” he said.

“What this underlines is that we’ve had a warm winter, we’ve had very little rain and once we get high winds – that’s all you need for grass fires to take off.”