DAILY Ex - 19 SEPTEMBER 2026

Operational Ex - restarting is a decision, not a button

Yesterday’s industry reporting brought a useful operational story from Spain.

ArcelorMittal has returned Blast Furnace A at Gijón to operation after a shutdown following a steam explosion on 9 September 2026.

According to reports citing the company, a burst water pipe caused the steam explosion. There were no injuries, damage was limited to structural elements around the platform, and the blast furnace itself was not damaged. The furnace was nevertheless safely shut down so the incident could be investigated and repairs carried out before restart. Blast Furnace B remained operating.

Important distinction:

This was not reported as an ATEX/IECEx or flammable-atmosphere explosion.

So why discuss it in Daily Ex?

Because the interesting part for a Head of Operations is the decision between incident and restart.

Something happened. The plant stopped. The problem was investigated. Repairs were made.

And eventually somebody had to decide: We can operate again. That same decision exists throughout the hazardous-area industry. After a trip, repair, shutdown, modification or abnormal event, the Ex question isn’t merely whether the machine runs. It is whether the plant has returned to its demonstrated/documented Ex-safe condition.

That may require confirmation that:

HAC assumptions remain valid → Ex equipment integrity is restored → ventilation/inerting/gas detection are available → temporary equipment has been removed or assessed → overrides are cleared → PTWs are closed → inspections are completed → deviations and MoCs are understood.

The Head of Operations doesn’t need to personally verify every Ex gland. But somebody must provide enough evidence for Head Operations to make the restart decision.

And that leads to today’s use case.

Operational Ex use case - “We only changed the product”

Imagine a production team wants to introduce another solvent or raw material into an existing process. No new machine. No new electrical installation. No construction project. From the production perspective, this can look like a recipe change.

From an Ex perspective, the question is different: Does the demonstrated safe condition still apply?

The new material may have a different flash point. Its vapour may belong to another gas group. Its auto-ignition characteristics may affect the required temperature class. Its release behaviour may alter the hazardous-area classification. For powders, particle characteristics and dust explosibility may change. And changing flow, transfer or material properties can also change the electrostatic charging situation.

Suddenly, the existing HAC, EPD/Explosion Protection Document, equipment selection and operating controls may no longer describe the process that is actually being operated.

This is exactly why Management of Change belongs in Operational Ex. The Head of Operations does not need to calculate gas groups, temperature classes or zone extents. The operational responsibility is more fundamental: Recognise that the change may invalidate an assumption - and don’t release it until the right competent person has checked it.

Today’s question for Head of Operations

Look at one product/raw-material change introduced during the past 12 months.

Ask: "Was it assessed against the existing HAC and Ex basis before production started?" If the answer is “I don’t know”, you have found something worth checking. Operational Ex isn’t about turning the Head of Operations into an Ex engineer. It is about knowing when to ask the Ex engineer before making the operational decision.

How does your site trigger an Ex review when the process changes but the equipment doesn’t?