Every employer engaged in building work must ensure that, where flammable liquids are used or applied at the workplace, this is done in such a manner an employer must ensure that no fire or explosion hazard is created, and the workplace is effectively ventilated: Provided further that where the workplace cannot be ventilated effectively the employer must provide every employee involved with a respirator, mask or breathing apparatus of a type approved by the chief inspector,* and must take steps to ensure that every such employee, while using or applying flammable liquid, uses the apparatus supplied to him.