Process Safety · Lesson 39 · 8 min read

The Injection Point Can Become the Corrosion Hotspot

A chemical injection connection can protect a process, improve separation or control deposits, yet it can also create a concentrated damage location. The main line may appear healthy while the pipe wall directly below an injection point loses thickness. Treat the point where the chemical meets the process as an integrity location with its own design, operating and inspection evidence.

The hazard mechanism: a useful chemical can be locally aggressive

A chemical that is suitable for the process does not automatically become harmless at the injection point. Before it disperses, a concentrated stream may contact a limited area of the pipe wall. Its composition, delivery arrangement, flow pattern and the receiving stream all influence where exposure occurs. Local damage can therefore be much more severe than an average corrosion rate suggests.

The UK Health and Safety Executive explains that localised corrosion can cause failure much sooner than uniform wastage would predict. HSE also says material selection and corrosion control should cover foreseeable changes in temperature, pressure and composition, supported by suitable inspection and maintenance. [3] The practical message is simple: do not use broad system condition as proof that a small, high-consequence location is healthy.

Official offshore learning: failure beneath the injection point

BSEE Safety Alert 319 describes an 18-inch low-pressure production header that ruptured on a Gulf of Mexico platform under normal working pressure. The rupture opened a long split, released production fluids, sprayed three workers and led to evacuation of the platform. BSEE concluded that corrosive loss of pipe integrity had occurred immediately below a chemical drip injection point used for an acidic demulsifier. [1]

The official investigation report gives important context. It identified internal corrosion as the likely cause and found metal loss at the ruptured piping. It also reported that chemicals had been introduced without injection quills that would have discharged them into the middle of the flow stream. The report said an earlier eight-point non-destructive examination had not tested at or downstream of the injection points, where the damage was developing. [2]

These facts belong to that incident; they are not a universal design rule for every service. The transferable lesson is to verify the intended injection arrangement and align inspection locations with the credible damage mechanism.

Why routine inspection can miss the real threat

An inspection programme can exist and still leave a local mechanism uncovered. A few acceptable readings elsewhere on a large header do not establish the condition immediately below an injection fitting or along the area affected by poor mixing. Inspection planning should start with the expected damage location and choose an authorised method capable of finding it.

Operating history matters too. A change in chemical, concentration, injection rate, nozzle or quill arrangement, process flow, shutdown practice or line-up can alter exposure. A repaired fitting is not necessarily the end of the issue if the surrounding pipe wall was not assessed. When leakage, blockage, repeated fitting damage or unexplained wall loss appears, treat it as evidence that the damage model and inspection scope may need review.

Hypothetical FPSO example: the records do not match the field

Hypothetical example—not a documented incident: An FPSO team prepares to restart a produced-water chemical injection package after maintenance. The drawing shows a quill, but the field tag and work record do not confirm what is installed inside the live header. Historic thickness readings are available on the straight pipe, although none clearly represents the injection location or the downstream mixing zone.

The supervisor does not treat the first chemical dose as a functional test of integrity. The restart is held within the installation’s approved decision process while operations, corrosion and inspection specialists reconcile the as-built arrangement, chemical service and examination evidence. Any required access, inspection or corrective work is planned under the applicable isolation and work controls.

The example does not prescribe a shutdown threshold, inspection technique or quill design. Those decisions depend on the service, equipment and competent technical authority. Its lesson is that uncertainty at a concentrated damage location is a reason to obtain evidence, not to assume the wider header represents it.

Critical controls and leadership actions

BSEE recommends procedures for the proper use, installation and verification of chemical injection equipment, together with visual and non-destructive examination of corrosive chemical injection points. [1] Leaders should translate that principle into clear ownership across process, corrosion, inspection, maintenance and operations disciplines.

First, keep the design basis traceable: what is injected, under which process conditions, through which installed arrangement and with what compatibility evidence. Second, make field verification part of the barrier. A drawing, purchase record or completed work order does not by itself prove the internal component or discharge position. Third, define inspection locations from the damage mechanism and preserve enough records to detect change over time.

Finally, manage changes deliberately. Replacing a chemical, altering its rate, modifying an injection fitting or operating at different flow conditions can change the corrosion threat. Confirm the assessment, inspection response and acceptance criteria through the installation’s approved management-of-change and integrity processes.

Three practical actions

• Reconcile: match drawings, chemical service, field identification and maintenance records so the installed injection arrangement is known.
• Target: ask whether the inspection plan covers the injection point and credible downstream damage zone with a suitable authorised method.
• Respond: escalate leakage, repeated fitting damage, blockage, unexplained wall loss or an unverified change before normalising the condition.

Technical video

No directly relevant official incident or technical video was verified for this lesson. The BSEE alert and investigation report below are the primary learning sources; unrelated promotional animations have not been embedded.

Takeaway and team discussion

Key takeaway: a healthy average thickness does not prove that the pipe wall beneath a chemical injection point is healthy.

Discussion question: which injection point has the weakest evidence that its installed arrangement and inspection locations match the actual corrosion mechanism?

Continue in the Process Safety hub, and connect this lesson with mechanical integrity and management of change.

Verified primary references

1. BSEE Safety Alert 319: Chemical Injection Point Corrosion Causes Production Header Failure, 29 February 2016.
2. BSEE accident investigation report: Green Canyon Block 338-A, 16 October 2015.
3. HSE Technical Measures Document: Corrosion and selection of materials—localised corrosion, materials and inspection principles.

Published and sources checked 21 October 2026. Educational discussion only: apply approved installation procedures, competent corrosion and inspection assessment, and applicable requirements. No universal inspection interval, thickness limit or permission to work on live equipment is supplied.

Discuss this article in the comments →

Register interest in future HSSE email updates