- OSH in general
- OSH Management and organisation
- Prevention and control strategies
- Dangerous substances (chemical and biological)
- Biological agents
- Carcinogenic, mutagenic, reprotoxic (CMR) substances
- Chemical agents
- Dust and aerosols
- Endocrine Disrupting Chemicals
- Indoor air quality
- Irritants and allergens
- Occupational exposure limit values
- Packaging and labeling
- Process-generated contaminants
- Risk management for dangerous substances
- Vulnerable groups
- Physical agents
- Psychosocial issues
- Sectors and occupations
- Groups at risk
There are six basic types of protective clothing against chemical and microbiological hazards: 1) gas-tight, 2) air-fed non-gas-tight suits, 3) suits against pressurised liquids, 4) suits against sprayed liquids, 5) suits against solid particles, and 6) suits offering limited protective performance against liquid chemicals. Furthermore, several subtypes exist. Within each type, the efficacy against different chemicals, microbes, and mechanical strength varies depending on the structure of the clothing and material properties. Clothing types 3, 4, and 6 may cover the user's body only partially. This article provides information about the selection, use, and maintenance of protective clothing against chemical and microbiological hazards.
Occupational risks relating to health and safety have to be managed, first by choices of the work methods and materials, second by technical measures, and lastly by the use of personal protective equipment (PPE)     . In an ideal situation, PPE should not be needed. In the workplace, the employer has to define the acceptable risk level which has to be at least the statutory occupational exposure level, but preferably less than that level.
PPE are often also needed during the time when new technical risk management measures are being planned, constructed, and introduced into use. When all the planned risk management measures are in place, the residual risk level needs to be controlled so that it remains below the acceptable risk level.
Personal protective equipment can be used for minimizing the risks, but very rarely can remove the entire risk. The efficacy of the protective clothing which is meant against chemical or biological hazards requires that it is chosen, stored, used, and maintained correctly. The usability and maintenance should be taken into account to match the protective clothing and its intended use.
The provision of protective clothing is covered by a European directive , which has been transposed into member state legislation. The main points of the directive are given below.
PPE must be used when the risks cannot be avoided or sufficiently limited by technical means of collective protection or procedures of work organization.
Employers' obligations: PPE must comply with the relevant provisions on design and manufacture with respect to safety and health (CE marking based on EU Regulation 2016/425/EU) .
All personal protective equipment must: - be appropriate for the risks involved, without itself imposing any increased risk - correspond to existing conditions in the workplace - take account of ergonomic requirements and the worker's state of health - fit the wearer correctly after any necessary adjustment - be provided free of charge and kept in good condition - be compatible with other PPE used. Workers must be consulted over PPE, and provided with instruction and training on its use.
Risk - combination of likelihood and severity of consequence
The decision to use PPE as a control measure and its selection needs to be based on a risk assessment.
Risk assessment should identify all hazards present and provide a measure of risk. Information should be available on the safe level of the hazards. Since the measure of existing risk and the safe level are known, it should be possible to decide how efficient the PPE needs to be. Physical, thermal and acoustic risks also need to be assessed in the selection of protective clothing in addition to the chemical and biological hazards. The likelihood of accidents has to also be assessed and realistic worst case scenarios are devised. The risk may concern the whole body or part of the body. The PPE should cover all body parts that are at risk. The use of the dust, liquid or gas tight clothing raises the risk of elevation of body temperature, which has to be taken into account in planning the task to be carried out.     .
Risk is a combination of likelihood of exposure and severity of consequence caused by exposure. Likelihood of skin exposure can be estimated in the following classes:
- very unlikely
- unlikely but possible
- multiple exposures likely
Severity of exposure can be:
- no effect
- treatable injury
- debilitating injury or
For chemicals, the hazard phrases from the safety data sheets should be used to assist in the assessment of risks. The risks for cancer, mutagenic or genotoxic effects, asthma, or intoxication are examples of the most severe hazards. Chemical burns may be classified into to several categories of severity. The effects of exposure to solvents may be irritation and discomfort, but long term inhalation or skin exposure may lead to severe nervous system disturbances .
Chemical protective gloves and clothing is needed when the chemicals are:
- allergic sensitizers
- skin carcinogens or
- pose a percutaneous risk.
The classification of chemicals on the safety data sheet informs about the hazards posed by the chemical in use. "Skin notation" next to the occupational exposure level signifies the percutaneous risk. Percutaneous risk means that the chemical can penetrate through the skin and cause effects e.g. intoxication, cancer, or other effects in a body. Currently the safety data sheets may also contain exposure scenarios, which directly inform about the kinds of risk management measures along with the protective clothing which should be used in specific tasks where hazardous chemicals are present.
The risk assessment needs to account for:
- type of [Dangerous substances (chemical and biological)|chemical/hazardous agent]]: solid, liquid, gas, vapour, aerosol
- duration of exposure (time in seconds, minutes or hours)
- contact characteristics such as continual contact, intermittent contact, accidental contact, amount of probable splash)   .
The protection of the health and safety of workers from the risks related to chemical agents at work is covered by a European directive , which has been transposed into member state legislation.
Viruses, bacteria, prions, fungi, and parasites are biological agents, some of which are hazardous. Safe air concentrations for hazardous biological agents are seldom known. The risk assessment has to focus on which kinds of hazardous biological agents are present, how hazardous are they, and what are the routes for exposure: (1) inhalation, (2) ingestion; (3) contact with the mucous membranes of the eyes or nasal tissues; or (4) penetration of the skin through lesions or abrasions . The hazardousness depends on the effects that the biological organism can cause and the treatability of the effects i.e. disease. The protection of workers from risks related to exposure to biological agents at work is covered by a European directive . In the directive, the biological agents are classified into four risk groups, according to their level of risk of infection:
- group 1: biological agent means one that is unlikely to cause human disease;
- group 2: biological agent refers one that can cause human disease and might be a hazard to workers; it is unlikely to spread to the community; there is usually effective prophylaxis or treatment available;
- group 3: biological agent means one that can cause severe human disease and present a serious hazard to workers; it may pose a risk of spreading to the community, but there is usually effective prophylaxis or treatment available;
- group 4: biological agent signifies one that causes severe human disease and is a serious hazard to workers; it may present a high risk of spreading to the community; there is usually no effective prophylaxis or treatment available.
The prevention of the disease requires a combination of measures such as isolation, hygiene, medication, vaccination, and PPE. Biological agents as liquid or solid organic airborne particles, behave in the same way in the air as inert or inorganic particles. Each type of organism has its size range that has to be taken into account for PPE selection.
Protective clothing against biological hazards may be needed in microbiological laboratories, biotechnological production, waste treatment, sewage work, caring for infected animals or humans, emergency clean-up, treatment of hospital risk waste, pandemic preparedness and response, crime scene investigation, and bioterrorism incidents .
Risks are also dependent on the human characteristics of the clothing users . The clothing itself may cause additional risk. Medical issues have to be considered: allergies, heat stress, physical stress, and psychic stress. Claustrophobia may prevent the use of encapsulating suits.
Protective clothing affects:
- heat stress
- ease of communication
- hand function (dexterity, grip, tactility)
- health of skin.
Poor motivation for using PPE correctly might be the highest risk factor, which may cause the PPE to fail to protect the wearer. The best cure is to make sure that PPE users are fully informed about the risks and the details of the methods that are used for managing the risk, as well as being themselves involved in the PPE selection process. Assessments on the efficacy of the risk management measures are needed.
Chemical protective clothing
Basic principles of selection
Where chemical exposure cannot be prevented by other means, individual protection measures including PPE needs to be applied . Chemical protective clothing (CPC) should be selected to reduce the hazardous exposure well below the danger level. The aim is that the exposure is not at the statutory occupational exposure level, but at a level which the employer can trust to be safe for the employee. For protection, only PPE that has a CE-mark should be used.
The first choice to be made is the clothing type. The types are categorised in accordance to the leak tightness and the structure of the clothing (Table 1). Second, the resistance to permeation or penetration by chemicals has to be considered. The clothing also needs to be of adequate mechanical strength to suit to the task to be carried out. Maintenance and user comfort must not to be overlooked. Many CPC materials catch fire easily. If this risk is present, the CPC needs to be selected accordingly. If the risk posed by the chemicals used concerns only a part of the body, the CPC can be selected to protect only that part of the body, e.g. arms. For such CPC, the letter marking PB (partial body) is added after the marking of the type. The CPC can be meant for limited use (or single use) or they can be reusable. The requirements for reusable CPC are usually stricter than for CPC for limited use .
One CPC product often represents several types. It is common that type 3 protective clothing is also a type 4, 5, and 6 clothing, and also clothing protecting against biological hazards and radioactive contamination.
Types of chemical protective clothing
Type 1 CPCs, gas tight suits, are divided into several sub-types. Type 1a has a breathable air supply inside the chemical protective suit. The air supply can be e.g. self-contained open-circuit compressed air breathing apparatus. In type 1b the breathable air supply is worn outside the CPC. In type 1c, a positive pressure of breathable air can be provided via air lines . Types 1a-ET and 1b-ET are meant for emergency teams . Type 1 CPC may be needed for example against dimethyl sulphate, ammonia, chlorine, cyanogen chloride, hydrogen cyanide, sulphur mustard, or Sarin.
The leak tightness for type 1a, and for types 1b in which the facemask is permanently joined to the suit, is ensured with a test that measures how pressurised air is held by the suit. Type 1b suits which have facemasks that are not permanently joined to the suits have to be tested with the same pressure test but also inward leakage test. The inward leakage shall not be greater than 0.05% when measured in the ocular cavity of the mask. Inward leakage test is also used for type 1c and type 2 suits.
Type 2 CPC are not gas tight and a positive pressure of breathable air is provided into the suit e.g. via air lines. The suits can be used against aerosols, sprays or gases, for instance in the manufacture of drugs or other hazardous materials, if the task requires that the employee stands still .
Type 3 CPC (and PB) has liquid-tight connections between different parts of the clothing. The CPC can be used in tasks where the contaminants are not air-borne, chemicals may splash under pressure, or the work space is confined and the employee has to lean on contaminated surfaces. The type 3 CPC is not tested for leakage of a gas or particles, but it is tested for leaks by compressed jets of water . The materials can be the same as those used in type 1 or 2 CPC.
Type 4 CPC (and PB) has spray-tight connections between different parts of the clothing. The CPC can be used in tasks where the contaminants are not air-borne, there is a risk of small splashes of chemicals, and the work space is not confined. The type 4 CPC is tested by spraying it with water  . The materials can be the same as for the type 5, but the seams are taped.
Type 5 CPC is intended for use against air-borne solid particles. It is often used to lessen the respiratory exposure such as those encountered in asbestos work and other tasks with hazardous dusts. The leak tightness of the suit is evaluated through two criteria.
One special test is for the total inward leakage (TIL), i.e. the overall mean penetration through the suit while worn by test persons in sodium chloride aerosol atmosphere. The TIL can be used as laboratory based efficacy measure for the CPC. For the type 5 CPC the TIL has to be less than 15% for 8 test persons out of 10 . This is a factor to be seriously considered while selecting the type 5 clothing against hazardous chemicals.
Type 6 CPC (and PB) is meant for tasks where limited protective against liquid chemicals is needed. The overall efficacy of the clothing is tested with a similar spray test as used in type 4 CPC, but with only 10% of the liquid load . The material efficacy against chemicals is measured in percentages, while the types 1–4 are classified in units of micrograms per square centimetres. The type 6 CPC should be only used against small and rare splashes of irritant substances.
CPC has several markings e.g. standard number, type, size and pictograms (Figure 2 and Figure 3).
The first marking means that the clothing is for protection against chemicals and the latter marking means that one must adhere to the manufacturer's instructions.
Leak tightness and resistance to permeation against hazardous chemicals are the two basic factors in selection of the CPC. Chemical permeation tests are required for types 1–4 CPC. The measure of chemical permeation is breakthrough time. It is the time elapsing between the initial application of a test chemical to the outside surface of a protective material and the time when the permeation rate through the material exceeds 1,0 µg x min-1 x cm-2 or 0,1 µg x min-1 x cm-2 . The breakthrough time is always specific for the pair: CPC material and chemical. Generalising the breakthrough times for materials types with the same material names is common, but this should be done with great caution, since the breakthrough time is not necessarily the same for the materials with the same names.
EN standards require the breakthrough times to be reported as protection classes (Table 2).
Table 2: Protection classes for chemical permeation and corresponding breakthrough times
|Protection class||Breakthrough time, min|
|1||10 - 30|
|2||30 - 60|
|4||120 - 240|
|5||240 - 480|
Source: EN 14325 
Breakthrough time is not same as the safe usage time of the clothing. Breakthrough times can be used in comparing several products and also as a warning about totally unsuitable products. The efficacy of the selected clothing has to be always related to the risks involved in the task.
Types 1a-ET and 1b-ET have to be tested against permeation of 15 chemicals that are listed in the standard EN 943-2 . The test chemicals represent a wide range of aggressive chemicals. Thus, the clothing that meets the requirements according to this standard, will offer protection against a wide range of chemicals. If the breakthrough time for those solvents, gases, acids and bases is not over 30 min, the instructions for use must clearly state that this CPC does not offer protection against continuous exposure to the chemical.
Chemical penetration concerning the type 6 of chemical protective clothing
In the test for chemical penetration, a small quantity of liquid is dispensed onto the surface of the protective clothing material, which is laid in an inclined gutter at an angle of 45°. The liquid is allowed to run off and the quantity that penetrates the material is measured. The type 6 CPC (and PB) will fulfill its requirements, if for one test chemical of those that are listed in the standard EN 13034, the penetration is less than 5%. The chemicals are sulphuric acid (30%), sodium hydroxide (10%), o-xylene, and butan-1-ol   Other test chemicals can also be used.
CPC must possess minimum performance requirements for mechanical strength. In laboratory tests preceding the EC type examination of types 1–4 clothing, the following mechanical properties are assessed:
- abrasion resistance
- flex cracking resistance
- flex cracking at temperature of -30°C (not mandatory test)
- trapezoidal tear resistance
- tensile strength
- puncture resistance   .
The same properties are measured and classified for the CPC types 5–6 with the exceptions that the tensile strength for type 5 and flex cracking for type 6 are not essential  .
The results of the assessment are given as protection classes in the CPC's instructions for use. Each class can be used in a comparison between different CPC. The larger the number of the protection class the better is the clothing with respect to that property .
Resistance to ignition
In the ignition test of the CPC, a flame is passed over the surface of the material. The material should not form droplets and should prove to be self-extinguishing . Passing this test does not mean that the CPC would not burn in fire. This requirement must be met for CPC of types 1, 2, 5, and 6.
Protective clothing against biological hazards
The statutes state the workers' exposure to biological hazards must be prevented. Where the exposure cannot be prevented by other means, individual protection measures including PPE must be used. Workers have to be provided with appropriate protective clothing or other appropriate special clothing .
According to the standard EN 14126 protective clothing against biological hazards is classified into the same types of leak tightness as chemical protective clothing . As a way of recognizing the clothing, the suffix B is added, e.g. type 3-B. The pictogram "protection against biological hazards" is also used (Figure 4).
The clothing materials are tested for resistance:
- Against penetration by contaminated liquids under hydrostatic pressure. This the only viral test for the clothing. There are six classes of hydrostatic pressure from 0 to 20 kPa, with bacteriophage PHI-X174 being used as a challenge virus, and the extent of penetration of the bacteriophage is examined.
- Against penetration by infective agents due to mechanical contact with substances containing contaminated liquids. In this test, rubbing and liquid migration may allow the staphylococcus aureus bacteria to penetrate through the protective material. Breakthrough time is the measure of the penetration. Times from 0 to more than 75 min are divided into 6 protection classes.
- Against penetration by contaminated liquid aerosols. The bacteria are measured as colony forming units, and the number of units is subdivided to 3 protection classes.
- Against penetration by contaminated solid particles. The bacteria are measured as colony forming units, and the number of units is subdivided to 3 protection classes.
In the selection of the protective clothing, one should be note that the efficacy offered by the protection class 1 is not very high. The larger the number of the protection class, the better is the clothing for that specific property.
Physical strain while using protective clothing against chemical and biological hazards
Working in impermeable protective clothing has significant effects on the thermal load generated by its users. The clothing limits heat and moisture transport and this leads to elevation of skin and core temperature. This can result in various health effects ranging from transient heat fatigue to serious illness, even death. The type of the clothing and its ventilation, the work activity, climate conditions, and the characteristics of the wearer of the clothing all influence the development of the heat stress   . CPC types 1–3 are made from impermeable materials, types 4–6 may also be made of microporous materials, but only type 6 materials can be breathable.
The physical performance of the users has to be examined before starting the occupational use of leak tight protective clothing and periodic examinations have to be conducted. Spiroergometry is used to evaluate Finnish chemical emergency rescuers .
The tasks need to be planned with care. The clothing user needs rest breaks. If the environment is hot and work load is heavy, the working time may have to be limited e.g. 20 min. The user should be monitored for physiological factors such as heart rate, temperature, and body water loss .
Ease of use and compatibility with other equipment
Protective clothing against chemical and biological hazards makes it more difficult to carry out the work, but the hindrance should be as small as possible. Comfortable work conditions make the work more efficient, and thus efforts should be expended in the selection of the clothing. The user has to be able to perform all the movements, assume the working positions he or she will have when performing the work, and be able to use the working tools. In order to ease the work load the clothing should be selected so that its donning and removal are easy. The removal has to be straightforward also since different kind of emergencies may arise, and the clothing may need to be taken off quickly. A poor fit of the clothing may result in reduced efficacy of the clothing  .
If other PPE are needed together with the protective clothing, the efficacy of the entire PPE has to be ensured. Special care has to be taken to ensure that the wearer, who has to wear hearing protection will be protected and be able to communicate and hear warning signals. Difficulties may also arise in combining gloves, footwear, respiratory mask, and eye shields so that they are tight enough. When using protectionagainst fall from heights, attention should be paid to the mechanical strength of the protective clothing.
Workers have the right to be consulted over the selection and purchase of protective clothing. Wearer trials are needed to ensure the usability of the protective clothing. An evaluation of the maintainability of the clothing is also needed before the selection.
The purchase of protective clothing should always be based on a risk assessment. Instructions for the purchase have to be clear. In order to ensure that the purchaser is sufficiently informed to be able to purchase the correct protective clothing, the purchaser should be involved in all the phases of the selection process. The suit which is evaluated as possessing proper materials and construction, and which conforms to the specifications should be purchased . Personal protective equipment must be provided free of charge by the employer to the employees.
The legislation requires workers to be provided with training on the use of protective equipment   . Training should be given to protective clothing wearers, supervisors, support personnel and others whose workplace role influences the clothing wearers. Information is needed on:
- workplace risks;
- reasons why the use of the clothing is necessary;
- the limitations imposed on the wearer by the clothing;
- personal responsibility for wear and care of the clothing
- possible causes for the inefficacy of the clothing;
- periods of work and rest;
- need for consumption of liquid, and
- decontamination procedures.
Provisions for self rescue and rescue assistance need to be planned in advance. One crucial part of the training is the response in the case of an emergency.
User training includes donning and removal of the protective clothing. The training should include pre-use checks, safe work methods and monitoring the clothing while in use. The user training should be carried out under realistic conditions and with actual equipment following the same procedures as in the real work task. In user training, the final check of size, fit, and compatibility is investigated. Training has to prohibit misuse due to a lack of understanding of clothing limitations, e.g. wearing a splash garment as a way to offering vapour protection.
Pre-use checks include checking for defects in:
- ensemble assembly
- garment and components
- interface (closure, zippers)
- sufficiency of ventilation rate (gas-tight clothing).
The training should be supported with regular refresher courses. Records should be kept for trainees, trainers and training content   .
Planned management of the care and maintenance of protective clothing is essential. Damaged protective clothing can put users at extra risk as they can have a false sense of security. The instructions for use of protective clothing contain guidance on cleaning and disinfection or decontamination as well as on storage. In addition for clothing made of treated materials, there needs to be information when the reapplication of repellance treatment is necessary. The manufacturer must also provide information about repair of the clothing        .
During decontamination, the contaminants are removed or neutralized from the chemical protective clothing. Gross decontamination allows the user to exit safely or remove the protection. Normal decontamination permits the reuse of the types of protective clothing that are reusable. Decontamination can be made physical (pressurised water, scrubbing) or chemical methods (inactivate the contaminant) or by using combination of these techniques. There has to be a plan for the decontamination process before allowing the workers to enter areas where there are hazardous substances. The decontamination procedure should not put other people or the environment at risk or damage the PPE. Workers assisting in decontamination also have to be protected. The effectiveness of decontamination should be checked e.g. visually searching for signs of discolorations, swelling, corrosive effects, stiffness or degradation of the material  . Single use clothing is used when the contamination cannot be effectively removed from the clothing. Single use clothing is commonly used against microbiological agents or hazardous dusts, e.g. asbestos.
The storage must be arranged to prevent damage to the suits. Exposure to sunlight, dust, moisture, chemicals, extreme temperatures and mechanical damages e.g. folding must be prevented. Potentially contaminated suits must be stored separately from normal work clothing and unused protective clothing.
Regular inspection is necessary and should include inspection when the clothing is first received, inspection when the clothing is selected for a particular chemical operation, inspected after use in training and previous maintenance, periodic inspection of stored equipment, and filling in an inspection questionnaire about cases. Records must be kept of all inspection procedures containing item identification number, date of inspection, person conducting the inspection, results, and unusual findings.
In all repair work, the manufacturer's instruction must be followed or the suit must be sent to repair location authorised by the manufacturer.
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