Two companies could face penalties of more than $1.5 million after being charged over separate Adelaide workplace accidents that occurred within 24 hours of each other.

Federal workplace health and safety regulator Comcare has filed legal proceedings in the Adelaide Magistrates Court against the national employers – waste management company Transpacific Industries and construction company John Holland.

Transpacific faces two charges of breaching the Work Health and Safety Act over a flash fire at its Wingfield Chemical Waste Processing Plant on July 25, 2013, which allegedly knocked a worker to the ground.

Comcare says the fire broke out during a trial to distil a new industrial solvent from a chemical waste product and resulted in the worker being treated in hospital for burns.

John Holland faces three charges following an incident the following day at the South Road Superway construction project, when a portal crane allegedly collided with an elevated work platform, leaving a worker requiring medical treatment.

Each offence carries a maximum penalty of $1.5 million.

“It is alleged that both companies failed to ensure, so far as was reasonably practicable, the health and safety of their workers and exposed them to a risk of death or serious injury or illness,” Comcare said in a statement today.

Dates have yet to be set for the hearings.