A university laboratory is not an ordinary classroom. It holds culture plates, incubators, specimen freezers, chemical cabinets, shelves of dried plants, soil and insect collections, and years of research notebooks. When floodwater reaches a teaching or research building, the damage goes far beyond wet floors and swollen benches. Flood mold can contaminate work that depends on very clean conditions, and it can affect the health of the students, lecturers and technicians who return to those rooms every day. This guide is written for lab heads, faculty safety officers, facilities teams and university administrators. It explains what post-flood mold does to a lab, why wiping with alcohol alone is not enough, and where ozone treatment fits into a safe recovery.

A Typical Scenario: Every Culture Plate Grew Mold

The science faculty of a university in Pathum Thani had to close its teaching building for almost three weeks after floodwater nearly a meter deep filled the ground floor. That floor housed the undergraduate microbiology lab, a plant and soil specimen store and the central instrument room. The second floor, home to the graduate research labs, stayed dry, but the power was off for the entire flood.

When the water went down, the facilities team shoveled out mud, washed the floors and opened the windows. Dr. Napa, head of the microbiology lab, went up to the research rooms for the first time. The fridge that had been without power for weeks released a rotten smell the moment she opened it. Paper specimen boxes on the lower shelves were covered in green spots, gray patches had appeared in the corners of the ceiling, and the air smelled damp in a way she had never noticed in a lab before.

The real worry began two weeks after the rooms reopened. Her master's students started new bacterial cultures, yet almost every plate showed mold contamination within two or three days, even though they worked in the clean bench exactly as before. Undergraduates in practical classes complained of itchy eyes and sneezing, students with asthma needed their inhalers more often, and a pregnant student asked to stay out of the lab. The team wiped benches with alcohol every day, ran the UV lamps longer and changed lab coats more often, but contamination kept coming back and a grant deadline slipped week by week. This is a typical scenario rather than one documented case, and it repeats at campuses in Nakhon Pathom, Chiang Mai, Ubon Ratchathani and Hat Yai whenever floods reach buildings with labs and specimen rooms.

Why a Flooded Lab Is a More Serious Mold Source Than an Ordinary Room

Molds common after floods include Aspergillus, Penicillium and Cladosporium, and where materials stay wet for weeks, Stachybotrys may also appear. Their spores are always in the air, but they only grow into colonies when they find moisture and food. A flood supplies both: weeks of high humidity and plenty of organic material. University labs add several complications that ordinary rooms do not have.

1. Labs are full of mold food

Culture media, agar, sugars, yeast extract, plant material, seeds, soil, food samples and the cardboard boxes that hold everything are all excellent food for mold. When the power fails, fridges and incubators stop, their contents spoil, and each unit becomes a large source of odor and spores every time the door is opened.

2. Specimen stores are often on the ground floor and sealed

In many older buildings, specimen stores, herbaria, wet collections and research archives sit on the ground floor because they are heavy, and many have no windows to keep out sunlight. They are the first rooms to flood and the last to dry. With almost no air movement, humidity lingers long after the water has gone.

3. Specialized ventilation

Labs have fume hoods, extract ducts and supply and exhaust grilles designed to control airflow, and some have extra filtration. If ducts or fans were submerged, or filters absorbed moisture during the outage, restarting the system pulls spores into the room continuously. That explains why plates keep getting contaminated even when benches are cleaned daily.

4. Building materials and furniture that absorb water

Benches in older labs are often plywood or particleboard with a chemical-resistant top. When the base sits in water, the core swells and holds moisture. Cabinets, gypsum walls, ceiling tiles and wall insulation also soak up water. Mold growing in these hidden places can release spores for months.

5. Chemicals and biological material mixed with floodwater

This is the most important difference. Floods can tip over bottles, wash off labels, crack containers and release biological samples. Before anyone thinks about mold or odor, every lab must be assessed and cleared of hazardous chemicals and biological material under the institution's own safety rules by its safety officer or lab manager. That work is not part of an ozone service and must be completed before any outside team enters.

Health Effects on Students, Lecturers and Staff

Lab users spend long hours inside. A practical class can last three hours, and graduate researchers may be in the lab day and night during data collection. Continuous exposure to air carrying mold spores deserves attention. Common symptoms include:

• Sneezing, a blocked or runny nose and throat irritation
• Itchy, red or watering eyes, which makes precise visual work harder
• Coughing, chest tightness, wheezing and asthma flare-ups
• Headache, fatigue and poor concentration
• Skin itching or rash where skin touches moldy surfaces or papers

Groups who need extra care

People with asthma, allergies or chronic lung disease; anyone with a weakened immune system, such as those on immunosuppressants or undergoing cancer treatment, for whom Aspergillus can cause serious infection; pregnant women; and senior staff with long-term conditions. Many universities also have a nursery or demonstration school on campus, and if those buildings are nearby or share an air system, young children are part of the picture too.

Workers and staff who waded through water or cleaned mud in the first days should see a doctor promptly if they develop fever, severe headache, calf pain, red eyes, diarrhea or an infected wound, and should mention their flood exposure. These can be signs of infections such as leptospirosis that need treatment. Ozone manages the building environment. It is not a medical treatment and never replaces seeing a doctor.

What a University Loses When Lab Recovery Is Incomplete

Lost and delayed research

Mold contamination in microbial, plant tissue or cell cultures means restarting whole experiments, some of which take months per cycle. Some field specimens can never be collected again. Delays ripple into grant reports, publications and students' graduation dates.

Rising costs

Media, reagents, consumables and staff time spent repeating experiments are hidden but significant costs. If mold is left long enough to spread, a full refit multiplies the bill.

Disrupted teaching

Practical courses cannot simply move online. If labs are not ready, hundreds of students may miss required sessions and practical exams must be postponed.

Credibility of results and lab standards

Labs that provide testing services or are preparing for accreditation must show that their environment is properly controlled. Repeated contamination after a flood may force a review of results and weaken client confidence.

Student and parent concern

When students start having allergy or asthma symptoms after lab sessions, word spreads quickly to classmates and parents. Clear communication about how the university restored the rooms, backed by records, goes a long way toward rebuilding confidence.

Common Lab Habits That Fall Short After a Flood

Wiping benches with alcohol every day. Alcohol suits routine cleaning of smooth work surfaces, but it never reaches mold in gypsum walls, ceiling tiles, bench cores or ducts, which are the real spore sources. If the source remains, new spores settle on the bench the next day.

Running UV lamps longer. UV only works where light falls directly. Shadows under shelves, behind cabinets, inside grilles and within porous materials receive nothing, and lamps must be maintained and replaced on schedule.

Painting over stains on walls and ceilings. Fresh paint looks clean, but if the wall is still damp inside, mold keeps growing beneath the coating and soon reappears.

Strong bleach everywhere. Bleach has a place on some hard surfaces, but in a lab it can react with chemical residues to release irritating fumes, corrode metal equipment and leave a chlorine smell that disrupts work.

Restarting ventilation right away. Without checking and replacing filters first, the system carries spores and odor from contaminated ducts straight into the room.

Moving specimens upstairs without sorting. Moldy boxes and papers moved unsorted into clean rooms spread the problem through the whole building.

All of these share one limit: they reach only visible surfaces or places light can touch. A flooded lab needs the whole room volume treated, including air, corners, the back of furniture and grilles, after damaged materials have been removed and the room dried.

WHD Ozone Treatment: A Supporting Step That Covers the Whole Lab Volume

World Health Disinfection (WHD) provides residential and building ozone disinfection for homes, condominiums, hotels, offices, factories, schools and hospitals. Ozone (O3) is a gas with strong oxidizing power. Released into a sealed room, it spreads into every corner, under shelves, behind cabinets, along ceiling joints and into grilles that cloths and UV light cannot reach.

Ozone breaks down the cell structures of viruses, bacteria and mold and breaks apart the molecules behind musty odor. It then reverts to oxygen (O2), leaving no chemical residue on benches, shelves or surfaces used for experiments, which matters in a lab where residues could interfere with results. According to the company, the service has been tested by Thailand's Department of Medical Sciences and Intertek (UK) for eliminating viruses, bacteria and mold at 99.99%, according to the test results the company has received.

Scope and safety to agree before work starts

• Ozone is used only in an empty, sealed room. No people, lab animals, pets or plants may be inside, and no one re-enters until the rest and ventilation period set by the team has passed.
• Hazardous chemicals, infectious waste, biological samples and flammables must be handled, moved or disposed of under university safety rules first.
• Sensitive items such as rubber parts, seals, tubing, high-value analytical instruments and specimens you still need should be removed, or discussed with the team first.
• Ozone comes after mud removal, washing, removal of damaged materials and drying. It does not replace any of those steps.
• Treating a room with ozone does not replace testing and certification of biosafety cabinets or specialized filtration, which must be done by specialists for that equipment.

How the work is done in labs and teaching buildings

1. Planning meeting with lab owners. Review rooms, work types, chemicals and equipment to be removed, and teaching schedules to avoid.
2. Site survey. Check the flood line, visible mold, moisture in walls and furniture, ventilation routes and sealed specimen rooms.
3. Zoning. Separate labs, specimen stores, instrument rooms, lecture rooms, staff rooms and corridors to plan concentration and sequence.
4. Room preparation. Close doors and windows, shut down or set ventilation as planned, open cabinets and drawers, post warning signs and block entrances.
5. Ozone release and contact time. Generators run until the target level is reached, then ozone works for the set time, typically about 30 minutes per zone.
6. Rest and ventilation. Ozone is allowed to revert to oxygen and the room is ventilated before staff return.
7. Final check and handover. The team checks odor room by room, advises on humidity control and provides information for the lab's own records.

10 Reasons Faculties and Universities Choose WHD Ozone Treatment

1. Whole-room coverage. Ozone reaches under shelves, behind cabinets and along ceiling joints, the hidden spore sources behind repeat contamination.
2. No residue on work surfaces. Ozone reverts to oxygen, so benches carry no leftover disinfection chemicals. Learn more about reducing chemical residue with ozone.
3. Clears musty specimen rooms. Sealed stores with built-up odor return to neutral air suitable for long working hours.
4. Tested and certified. Tested by the Department of Medical Sciences and Intertek (UK) for 99.99% elimination of viruses, bacteria and mold, according to the company's certified results.
5. Fits around teaching. About 30 minutes per zone makes it easy to schedule rooms outside class times.
6. Works with your safety officers. The team follows institutional procedures and starts only after chemicals and biological materials have been cleared.
7. Less unnecessary demolition. Remove only what is truly damaged and use ozone for rooms that are structurally sound, keeping budgets under control.
8. Experience across building types. From homes and offices to factories, schools and hospitals. See the ozone disinfection service page.
9. Pairs with surface disinfectants. High-touch surfaces can be treated with Chemgene disinfectant as the team advises.
10. A useful bonus. A free medical-grade disinfectant spray with any ozone job of 15,000 baht or more, handy for staff rooms and common areas after reopening.

The Lab Before and After Ozone Recovery

Note: results depend on handling chemicals and biological materials, removing damaged materials, drying, and controlling humidity after treatment.

Example Case: A Herbarium and Plant Lab in Chiang Mai

This example case is an illustrative scenario based on common patterns, intended to show the right recovery order.

Thana, a staff scientist at an agriculture faculty in Chiang Mai, looks after a dried plant collection and a plant tissue culture lab. Water from the Ping River entered the ground floor at about forty centimeters for several days. The lowest specimen cabinets were submerged, while the upper cabinets stayed dry but sat in very humid air. Afterwards the whole room smelled musty, and tissue cultures next door showed unusually high mold contamination.

Recovery began with sorting. Thana's team moved dry specimens to a humidity-controlled room upstairs, and soaked specimens were separated to decide whether to conserve them or photograph them before disposal. The safety officer handled the chemicals in the tissue culture lab. Contractors removed the wet lower section of gypsum walls, took out swollen plywood cabinets, washed the floors and ran dehumidifiers until the walls were dry. Facilities replaced the ventilation filters for the whole floor.

Only once the rooms were empty and dry did the WHD team treat the specimen store, the tissue culture lab and the ground-floor corridor zone by zone over a weekend with no classes. Entrances were blocked, no staff were in that part of the building, and people returned only after the rest and ventilation period. Thana said the musty smell disappeared and contamination rates returned close to pre-flood levels. He stresses that sorting specimens and drying the rooms mattered most, and ozone was the final step that finished the job properly.

Recovery Checklist for Flooded Labs and Teaching Buildings

Right after the water recedes

• Keep general staff out of labs until the safety officer has assessed chemical, biological and electrical risks.
• Wear protective clothing, gloves, boots and a suitable mask for any cleanup.
• Photograph damage, list losses and record the flood line for insurance and repair budgets.
• Handle fridges and incubators that lost power under infectious waste rules.

Before ozone treatment

• Remove or secure hazardous chemicals, flammables and infectious waste according to procedure.
• Sort moldy specimens, papers and cardboard boxes, keeping them away from clean items.
• Remove wet gypsum, insulation, ceiling tiles and plywood furniture.
• Wash floors and hard surfaces and run dehumidifiers until materials are genuinely dry.
• Replace ventilation filters and have fume hoods and biosafety cabinets checked by specialists.
• Remove high-value instruments and items with rubber parts, or consult the team.
• Make sure no people, lab animals or plants remain in the area.

After ozone treatment

• Re-enter only after the rest and ventilation period advised by the team.
• Clean work surfaces using the lab's normal procedures before experiments resume.
• Run small checks first, such as settle plates to monitor airborne contamination, before restarting main research.
• Keep specimen rooms under humidity control and check corners for mold regularly.
• Record the full recovery process in the lab's files.

Frequently Asked Questions

1. Can ozone replace normal lab cleaning?

No. Ozone is a supporting step after mud removal, washing, removing damaged materials and drying. Afterwards the lab still cleans its work surfaces according to its own procedures before experiments begin.

2. Do chemicals have to be removed first?

They must always be assessed by the institution's safety officer first. Damaged, leaking or unlabeled chemicals are handled under procedure, and the team should be told what remains in the room so both sides can plan.

3. Does ozone affect scientific instruments?

Some materials, such as natural rubber and certain seals, can degrade with repeated exposure to concentrated ozone. Remove high-value instruments or agree protective measures with the team.

4. How long must rooms be closed?

About 30 minutes per zone, plus preparation and the rest and ventilation period. The team schedules rooms around teaching.

5. Does ozone replace biosafety cabinet certification?

No. Biosafety cabinets and specialized filtration must be tested and certified by qualified specialists on their required schedule.

6. What if students develop allergy or asthma symptoms after lab sessions?

They should stay out of that area and see a doctor. Anyone with fever or calf pain after wading through floodwater should see a doctor immediately and mention the exposure. Ozone treats the environment, not people.

Get Your Labs Ready for Teaching and Research Again

Talk to WHD about surveying teaching buildings, labs and specimen stores, and plan ozone treatment together with your faculty safety officer.

Book Post-Flood Lab Ozone Treatment

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

Free medical-grade disinfectant spray with any ozone job of 15,000 baht or more.

Related Services

• Residential and Building Ozone Disinfection
• Chemgene Surface Disinfectant
• WHD Certifications
• Contact WHD

References

• World Health Organization fact sheets
• CDC: Floods and cleanup safety