South Korean petrochemical firms are bolstering safety measures to avoid violating a new workplace disaster law, which sends CEOs to prison in case of fatal accidents.

According to industry sources Monday, petrochemical firms are on edge after an explosion killed four workers and injured four others at Yeochun NCC’s factory in Yeosu, South Jeolla Province on Friday.

Due to the accident, Yeochun NCC is likely to become the first petrochemical firm to be punished by the controversial workplace disaster law enacted last month, under which owners and CEOs of companies with five or more employees can face a minimum one-year prison sentence or a fine of up to 1 billion won ($833,600) in the event of serious workplace disasters.

The explosion at Yeochun NCC startled Hanwha Solutions, which holds a 50 percent stake in the company. The accident came as a shock, as Hanwha Solutions’ chemical division launched an Environmental Health and Safety Management Committee just two days before the explosion.

Upon launch of the committee, Hanwha Solutions pledged to have zero workplace accidents and disasters, and to establish a culture where staff and executives voluntarily abide by safety, health and environmental standards. However, the committee and pledge had apparently failed to prevent the explosion at Yeochun NCC.

Meanwhile, other petrochemical firms are making all-out efforts to prevent a second Yeochun NCC case. In June, LG Chem launched the “Magnolia Project” to overhaul its safety system at work sites. Lotte Chemical recently applied strengthened safety regulations to all work sites, and aims to spend 500 billion won over the next three years on safety measures. Meanwhile, Kumho Petrochemical last year conducted an organizational reshuffle and created a new task force dedicated to safety.