A Story From the Field: A Workshop That Fell Silent

Khru Weerapong heads the automotive department at a vocational college in Mueang Nakhon Nayok district. Every October, his workshop is normally full of noise: wrenches clattering on concrete, engines turning over, and the laughter of vocational certificate and diploma students working in teams around the training benches. This year was different. After days of relentless rain, the Nakhon Nayok River broke its banks. Water flowed into the college grounds and sat in the ground-floor workshops at roughly forearm height for five days.

On the day the water finally drained away, Khru Weerapong pulled on his rubber boots and walked into the workshop. A thin layer of mud covered the concrete floor and had started to dry into flaky plates that cracked under his feet. The smell was not the familiar, almost comforting smell of engine oil that he had worked with for twenty years. It was a damp, sour mustiness mixed with mud and the unmistakable odor of drains.

The training engines used for strip-down and rebuild practice were coated with a cloudy film of dried floodwater. The bottom drawers of the steel tool chests still held standing water. In the tool store at the back of the workshop, the plywood shelving had started to grow white mold along its edges. In the changing room, the overalls that students had left hanging on hooks were covered in black spots of mold, and the safety boots lined up underneath gave off a smell that made him turn away.

In a few weeks, several hundred students would be back for practical training. At a staff meeting, the college director asked a simple question: "When will the technical departments be ready, and how can we be sure the workshops are safe for students?" Khru Weerapong knew that simply hosing down the floor was not going to be a good enough answer.

Vocational colleges across Nakhon Nayok, Prachinburi and Pathum Thani are facing similar questions this month. Workshops are a special case. They combine large open floors, heavy machinery, tools that rust, flammable materials, porous storage and changing rooms full of damp clothing. Getting them back into service needs a plan that respects all of these at once.

Why a Workshop Is Riskier Than It Looks After the Water Recedes

Germs from floodwater. Water that has crossed fields, villages and drainage channels carries bacteria such as E. coli and the organisms responsible for leptospirosis. These germs settle in the mud on the floor, under vice benches, in the gaps of tool cabinets and on the handles of the tools that students hold every day. Technical students also tend to have small cuts and scrapes from sharp metal and rough components. Those small wounds are an easy entry point for infection, which makes workshop hygiene more important than in an ordinary classroom.

Mold in porous materials. Plywood shelving, cardboard parts boxes, cleaning rags, cotton overalls and ceiling boards are ideal places for mold to grow. A closed workshop full of trapped humidity allows mold to spread quickly. Airborne spores trigger allergies, sneezing, blocked noses and asthma, and they settle back onto surfaces, starting new colonies wherever conditions are damp.

Odors that make training impossible. Mud, drain smells and musty dampness mixed with the oil and solvent smells of a workshop make the air thick and unpleasant. Some students feel dizzy or nauseous. Teachers end up shortening practical sessions, which affects learning outcomes and assessment schedules.

Costs that spiral. If mold is left to spread through the tool store, shelving, wooden cabinets and training materials that could have been saved may need to be thrown away. A department's limited budget then goes on replacing basics instead of improving teaching.

Confidence of parents and industry partners. Parents want to know their children are returning to a safe environment. Companies that take students on dual-vocational placements also want to see that the college takes its learning environment seriously. A clean, well-managed recovery strengthens those relationships.

Common Fixes That Fall Short

High-pressure washing everything. A pressure washer is excellent for blasting mud off concrete. But if it is aimed carelessly into tool chests, control panels or electrical boxes, it drives moisture deeper into places that are hard to dry. Germs also remain on surfaces that were washed but never disinfected.

Pouring bleach on the floor. Bleach kills some germs on smooth surfaces, but it is corrosive to metal. In a workshop, that means faster rusting of tools, engine parts and machine beds. It also does not penetrate plywood or fabric where mold has taken hold.

Leaving the big doors open. Ventilation is good, but natural air flow alone does not disinfect anything. During a rainy period, opening up the workshop can even bring more humid air inside.

Spraying air freshener. It masks the smell for a few hours. The musty odor from the real source soon returns, and the combination of artificial fragrance and engine oil often makes the air feel worse, not better.

Each of these steps has a place in recovery. Washing, drying and ventilation are all necessary. What is missing is a proper disinfection stage and a way to deal with mold and odor inside materials that cannot simply be scrubbed.

The Solution: Chemgene HLD4H Fogging and Controlled-Dose Ozone Treatment

World Health Disinfection offers a professional disinfection fogging service using Chemgene HLD4H disinfectant, delivered through ULV fogging equipment. The fine mist travels under vice benches, into the gaps of tool chests, around machinery and into corners of the workshop that a mop will never reach. After fogging, our ozone treatment service allows ozone gas to move into porous materials, fabrics and enclosed spaces, acting on mold spores and breaking down odor molecules at the source rather than masking them.

Our Process for Workshops and Tool Rooms

1. Site survey. We walk through each department's workshop with the head teacher, recording flood height, areas of mold, damp materials and items that should be discarded.
2. Clean-up guidance. We recommend shoveling out mud, washing floors and removing badly damaged materials first: soaked cardboard, mud-covered rags and swollen, broken plywood shelving.
3. Area preparation. Electrical circuits that have not yet been inspected are switched off. Fuel cans, thinners and other flammable materials are moved outside the treatment area. Electronic measuring equipment, vehicle diagnostic scanners and items with delicate rubber parts are covered or removed.
4. Disinfection fogging. We fog floors, walls, vice benches, tool chests, handles, stair rails, changing rooms and department toilets.
5. Ozone treatment. The area is closed and treated with ozone at a dose controlled to the room volume. Tool stores and changing rooms with strong odors receive particular attention.
6. Ventilation. Large doors are opened and industrial fans are used to clear the air. Teachers and students only re-enter once the ozone has broken down.
7. Re-check. We check odor and visible mold together with the teaching staff. If walls or shelving are still very damp, we suggest a follow-up treatment once they have dried.

Safety note: No people, animals or plants may be inside during ozone treatment, and the area must be fully ventilated before re-entry. High concentrations of ozone can age some rubber and plastic parts faster than normal. That is why our team controls the dose carefully and always recommends covering or removing drive belts, rubber hoses, seals and sensitive electronics before treatment. Ozone treatment is never carried out where gas cylinders or flammable liquids remain in the space.

Department-by-Department Considerations

Automotive. Training engines, vehicle lifts and parts cabinets have countless nooks and crannies. Teachers should strip, clean and lubricate submerged components according to good mechanical practice. Our team takes care of disinfecting the surrounding work areas, benches and storage.

Machine shop. Lathes, milling machines and drill presses should be inspected by the responsible teacher before use, and protected from rust by wiping and oiling. The floor, benches and surrounding surfaces are fogged with disinfectant.

Electrical and electronics. Training panels, multimeters and measuring instruments should be removed or covered before ozone treatment. A qualified electrician must check the wiring and breakers before power is restored.

Welding and fabrication. Gas cylinders must be removed or have their valves securely closed and be taken out of the treatment area. We will not run ozone in a space that still contains gas cylinders or flammable materials.

Changing rooms and lockers. Damp overalls and safety boots are one of the strongest odor sources in any workshop building. We recommend students take their overalls home and wash them in hot water. The empty changing room and lockers are then fogged and ozone-treated.

Classrooms attached to workshops. Many departments have a theory room beside the workshop. These rooms often have fabric chairs, notice boards and ceiling tiles that absorbed moisture and can be treated alongside the workshop.

10 Reasons Vocational Colleges Choose Fogging and Ozone Treatment After a Flood

1. Disinfection fogging covers the large floor area of a workshop quickly.
2. The fine mist reaches inside tool chests and under machinery, where hand cleaning is difficult.
3. Ozone treatment reduces musty odors in closed tool stores and changing rooms.
4. It lowers the risk of leptospirosis and skin infections for students who often have small cuts from technical work.
5. Chemgene HLD4H leaves no harsh chemical smell, so the space can be used soon after ventilation.
6. Controlled ozone dosing limits the effect on rubber parts and electronics.
7. Practical classes can restart close to the original timetable, reducing postponed practical exams.
8. It saves budget by rescuing shelving and training materials that can still be recovered.
9. It gives the college a clear process to report to management and share with parents.
10. A mosquito spraying service can be added around buildings while standing water remains.

Before and After Workshop Recovery

A Word From a Head of Department

"At first I was worried that ozone would damage our belts and rubber hoses. The team explained exactly what to cover or move out, and they controlled the amount for the size of each room. Afterwards, the tool store that used to smell terrible was much better. The students came back to training and nobody complained about the smell again."
— Head of a technical department at a vocational college in Mueang Nakhon Nayok (a representative field scenario)

Practical Advice for Teachers and Technical Students

• Wear rubber gloves, boots and a face mask while shoveling mud and moving equipment.
• Wash, dry and oil submerged metal tools as soon as possible to limit rust, and set damaged tools aside for inspection.
• Have an electrician inspect wiring and breakers before any machine is switched on.
• Throw away mud-soaked rags and cardboard boxes. They are mold sources that are very hard to clean.
• Wash hands with soap after handling tools or cleaning, and keep cuts covered and away from dirty water.
• Anyone who waded through floodwater and then develops a high fever, headache or muscle pain, particularly in the calves, should see a doctor promptly and mention the flood exposure. Guidance is available from the Department of Disease Control.

Planning the Restart of Practical Training

A workshop recovery goes most smoothly when the college treats it as a short project with clear owners and dates. Here is a simple framework that many technical departments find useful.

Assign one coordinator per department. The head of each department knows its equipment best. They can decide what must be removed, what can stay covered and which rooms are needed first.

Separate the jobs. Mud removal and rubbish disposal are done by college staff and volunteers. Electrical checks are done by a qualified electrician. Tool care and machine inspection are done by teachers. Disinfection fogging and ozone treatment are done by a specialist team. Keeping these jobs separate avoids confusion and makes sure nothing is missed.

Work from the most urgent timetable backwards. If the automotive department has practical assessments in the first week of term, start there. Theory rooms and storage areas that are not urgent can follow.

Record what was done. A short log with dates, rooms, and the steps taken is valuable for management reports, insurance discussions and communication with parents and industry partners.

Plan a follow-up check. Concrete walls and wooden shelves can take weeks to dry completely. Schedule a quick inspection a few weeks after reopening, and call us if new mold or odor appears.

Involve the students where it is safe. Senior students can help with supervised tasks such as sorting tools, cleaning and oiling hand tools, and recording inventory once the mud has been removed and the area has been disinfected. This speeds up recovery, gives them a sense of ownership over their workshop, and keeps them away from the riskier early clean-up work that is better left to adults with proper protective equipment.

Keep communication simple. A short message to parents and partners, explaining which workshops were treated, when they reopen and what precautions are in place, is usually enough to answer most concerns before they turn into worries.

Understanding Ozone and Workshop Materials

Teachers in technical departments know their materials well, so it is natural that they ask detailed questions about how ozone interacts with the things in their workshop. Here is a plain explanation of what we consider when planning a treatment.

Metals. Steel tools, cast-iron machine beds and aluminium parts are not meaningfully affected by a controlled, short ozone treatment. The far bigger risk to metal is the floodwater itself and the humidity that follows. That is why wiping, drying and oiling tools quickly matters so much more than anything else.

Rubber and some plastics. Natural rubber and certain soft plastics can age faster with repeated or very high ozone exposure. Drive belts, hoses, seals, gaskets and wiring insulation on training rigs fall into this group. Our approach is simple: control the dose to what the room actually needs, keep the treatment time appropriate, and cover or remove sensitive rubber items beforehand.

Electronics. Diagnostic scanners, oscilloscopes, multimeters, programmable controllers and computers should be removed or covered. Their bigger enemy is moisture that got inside during the flood, so they should also be checked by a qualified person before being powered on.

Fabrics and porous materials. This is where ozone is most useful. Overalls, seat covers, foam, plywood and ceiling boards absorb odors and harbor mold in ways that surface cleaning cannot fully reach. Ozone gas can penetrate these materials and act on the odor and spores inside.

Flammable liquids and gases. Fuel, thinners, paints and gas cylinders must always be removed from the area before fogging or ozone treatment. This is a firm rule for every job, not just for workshops.

Why Hygiene Matters So Much in Hands-On Learning

In an ordinary classroom, students mostly touch their own desk, pen and notebook. In a workshop, they share almost everything. A single socket set might pass through a dozen pairs of hands in one morning. Students lean on the same benches, grip the same vice handles, pull the same drawer pulls and wipe their hands on shared rags. They also touch their faces, eat snacks during breaks and sometimes skip washing their hands when they are in a hurry to finish a job.

That shared contact is part of what makes practical learning valuable, but after a flood it also means that any germs left on surfaces can travel quickly between students. Disinfecting the workshop thoroughly before students return, and encouraging regular hand washing afterwards, is a simple way to protect everyone.

It is also an opportunity to teach. Technical students will go on to work in garages, factories and construction sites, many of which may also face floods in the future. Showing them how a professional recovery is planned and carried out, with attention to safety, sequencing and documentation, is a practical lesson in workplace responsibility that they will carry into their careers.

Frequently Asked Questions

Q: Will the disinfectant make our tools rust?
A: Chemgene HLD4H is not corrosive in the way bleach is. However, any tool that was submerged should still be wiped and oiled according to normal workshop practice after cleaning.

Q: Do we need to move machinery out of the workshop?
A: Not for large machines. Their electronic controls should be covered, and small measuring instruments should be removed before ozone treatment.

Q: We have fuel cans and thinners in the store room. What should we do?
A: All flammable materials must be moved outside the treatment area before work begins. This is a safety requirement for everyone.

Q: Can you treat one department at a time?
A: Yes. We can schedule departments in order of urgency, based on each department's practical timetable.

Q: When can staff go back in after ozone treatment?
A: After the area has been ventilated and the ozone has broken down. Our team will tell the teachers when it is safe to reopen.

Q: Which areas do you serve?
A: Mueang Nakhon Nayok, Ban Na, Ongkharak, Pak Phli and nearby provinces including Prachinburi, Pathum Thani and Chachoengsao.

Bring the Sound of Engines Back to Your Workshop

Talk to World Health Disinfection about a fogging and ozone treatment plan for workshops, tool rooms and teaching buildings at vocational colleges in Nakhon Nayok.

See Our Disinfection Service – Click Here

Book Ozone Treatment – Click Here

Call 065-556-6294 · LINE @whd268 · worldhealthdisinfection@gmail.com

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References: WHO – Floods and health and the Department of Disease Control, Ministry of Public Health.