Chlorine accident

This is to inform you – in accordance with the Chemicals Act – of the possible risk of a chlorine accident and to provide you with basic instructions in the event of a chlorine accident at the Ülemiste Water Treatment Plant. Tallinna Vesi does everything in its power to ensure that the risk of such accidents is minimised by following all safety requirements during transport, storage and use of chlorine.

The Ülemiste Water Treatment Plant produces drinking water from surface water. In this process, chlorine is used as a disinfectant chemical.

There are several protective mechanisms in place to keep risk factors under control. We provide regular training for our staff and organise training exercises. We also work closely with the Estonian Rescue Board to be prepared to act quickly in the event of major accidents.

Tallinna Vesi has an operating authorisation No OKK-19-11 issued by the Estonian Consumer Protection and Technical Regulatory Authority on 28/11/2011 for an indefinite period. The hazardous chemical is handled at the water treatment plant, operated by Tallinna Vesi at Järvevana Road 3 in Tallinn. Due to the storage and use of chlorine, the Tallinn Water Treatment Plant is classified as a category B enterprise with a major hazard. This major hazard is a large-scale chlorine leak.

Tallinna Vesi has prepared and submitted to the competent national authorities a chemical data sheet, a risk analysis, a description of the safety management system and an emergency plan. Information on the date of the latest state supervision exercised on site can be found on the website of the Estonian Rescue Board (Enterprises with a major hazard and dangerous enterprises > Estonian Rescue Board (rescue.ee)), and detailed information on the inspection plan can be obtained from the Estonian Rescue Board (rescue@rescue.ee) and the Estonian Consumer Protection and Technical Regulatory Authority (info@ttja.ee, phone +372 667 2000). A detailed safety data sheet on chlorine is available.

The map below shows the chlorine accident impact zone:

Chlorine gas is toxic when inhaled, suffocates, irritates the eyes, skin, and respiratory tract.

Chlorine has a strong oxidising effect and is extremely toxic to aquatic organisms.

Chlorine gas is a greenish-yellow gas with a pungent odour, heavier than air. A cloud of chlorine spreads downwind from the accident site. It combines with water vapour in the air to form a white mist. Gas accumulates in lower places, ditches, and underground communications as it spreads downwind. Chlorine gas evaporates into the atmosphere with rising air currents.

Nature of a major accident risk, scenario and possible impacts:

Damage to container during chlorine transport
Leakage is unlikely, but the chlorine container may be damaged during transport and may break to a greater or lesser extent. To prevent accidents, Tallinna Vesi implements all precautionary measures and has prepared an emergency plan.
Fire and explosion risk
The risk arises when a container overheats. Following a possible explosion, a large amount of chlorine would be released into the air. The risk factor is minimised by continuous inspection and maintenance of the containers and by following all safety requirements when handling chlorine.

Measures applied to limit consequences

Human factor
The staff involved in working on hazardous sites are trained and have a relatively long working experience, including workplaces and equipment provided with appropriate instructions.
Personal protective equipment
Various personal protective equipment and measuring instruments are in use.
Accident recovery tools
Neutralising agents and sufficient water supply are in use.
Action in case of fire
Basic firefighting equipment and adequate water supply are available.

How to recognise intoxication?

Chlorine causes damage to tissues, irritates mucous membranes, causes a dry cough, runny nose, and sometimes vomiting.
Higher concentrations may cause chest pain, tears and coordination disorders.

How to act in case of a chlorine accident?

In case of an emergency, a signal “Attention everyone!” will be sounded at the plant by activating the warning siren (60 sec siren / 30 sec pause / 60 sec siren / 30 sec pause / 60 sec siren) along with the notification in Estonian „Tähelepanu – klooriavarii!“ (“Attention – chlorine accident!”) Note! The siren is not heard in the entire impact zone, but only in the nearby residential buildings (Järvevana Road 3). Act according to the notifications and instructions given by the rescue service.
- The test siren will last for 30 seconds along with the notification in Estonian „Tähelepanu – tegemist on katsetuse/õppusega“ (“Attention – this is a test / training exercise”). The siren is tested quarterly, 4 times a year, and the training exercises are organized once a year (exact times have not been set).
If you are in the impact zone at the time of the accident, you will also receive a message from the Estonian Rescue Board.
In the event of an accident, follow all instructions given by the rescue service.
When outdoors, immediately leave the impact zone, moving crosswind.
Use a wet towel or other cloth to breathe if you smell chlorine. If the smell of chlorine is strong, use a shower – water neutralises the chlorine gas.
If possible, go to higher floors indoors and stay there. Close the doors and windows, vents and ventilation.
When in the car, close the doors and windows, turn off the ventilation, and drive away from the impact zone.
Inform your neighbours of the danger.
Turn on one of the two ERR’s (Estonian Public Broadcasting) radio stations (Vikerraadio or Raadio 4) and listen to the instructions given there.
Turn on the TV channel ETV and listen to the instructions given there.
Information is also available from the Estonian Rescue Board (rescue.ee) and from the state helpline 1247.

Handler of the hazardous chemical: AS Tallinna Vesi, Water Treatment Plant, Järvevana Road 3

Information on safety measures and other chlorine-related questions:
Water Treatment Plant Manager: 62 62 510
Technologist: 62 62 610
Chief Operating Officer: ivar.ruubel@tvesi.ee
Technologist: ae.leier@tvesi.ee

Information on chlorine accident can be found on the website at www.tallinnavesi.ee

Information was prepared by: Ae Leier (updated: 12/06/2024)

In accordance with the Chemicals Act, Tallinna Vesi is sending information leaflets by post to all customers within a 2.7 km radius of the Ülemiste Water Treatment Plant from 1 to 5 February 2025, providing information and instructions in the event of a possible chlorine accident. This is a regular proactive notification. The risk of a chlorine accident has not increased. Information leaflet in Estonian and in Russian is available HERE.