Ranking of methods of protection against harmful production factors

The following is one of several possible schemes for ranking protection methods by their effectiveness ^[1] :

1. Elimination of a harmful physical factor , or replacement of a toxic substance with a non-toxic one.
2. Change of technology and replacement of equipment to mitigate the harmful effects:
   1. Change the physical properties of the materials used.
   2. Change of working methods, excluding contact of workers with harmful substances;
   3. Separation of places of hazardous work from locations of people;
3. The use of collective protective equipment that reduces the impact of harmful factors;
4. Organizational safeguards;
5. Use of personal protective equipment .

The following is a list of protection methods with some examples showing their effectiveness.

Elimination of a harmful physical factor, or replacement of a toxic substance with a non-toxic or less toxic

An example would be Germany's rejection of nuclear power . The complete absence of radioactive substances in power plants guarantees the absence of radioactive contamination even in the event of a terrorist attack or direct hit by a large meteorite . Replacing the riveted joint in shipbuilding with welding eliminated excessive noise exposure ; Noise reduction at textile enterprises was achieved by replacing machines with less noisy ones ( jacquard ones with automatic shuttleless ones ^{[2] [3]} ).

Technology change to mitigate the effects

Examples - The National Institute of Occupational Safety and Health for the prevention of industrial-induced hearing impairment due to industrial noise has created a database with information on alternative equipment that creates less noise. The work was performed as part of the Buy Low Noise program ^[4] . The transition to electrodes with a rutile- containing coating, without manganese, has led to a significant reduction in the incidence of pneumoconiosis and the number of cases of manganese intoxication ^[5] .

Change the physical properties of the materials used

Examples for protection against dust are the replacement of fine dusty powders with a solution; replacing dry grinding with wet ^[7] .

Changes in working methods that exclude contact of workers with harmful substances

Examples are special sealed containers, sealed places for overflow of toxic liquids, etc.

Separation of hazardous work sites from human locations

Examples are mining automation ; use of remote control .

Collective defense technology

Ventilation may be used to protect against air pollution; appropriate noise shields can be used to protect against noise and heat radiation. When working in a heating / cooling microclimate, and to protect against air pollution, air showers can be used. To protect against vibrations, vibration isolation can be used - both as a source of vibrations and in jobs of people ^[8] .

A serious drawback of collective protective equipment is that, compared to personal protective equipment, they are less universal. For example, if a respirator with anti-aerosol filters can be used both to protect a miner from dust at a depth of more than 1 km, and to protect a health worker from infectious aerosols (without any alterations); then the irrigation system used to reduce the concentration of coal dust in the face cannot be used to protect against aerosol in a medical facility. Replacing aerosol filters with gas filters, the same respirator can be used in the chemical industry ; ventilation and gas-cleaning equipment are not universal, and its design is highly dependent on the process and application conditions.

This drawback contributes to the fact that in practice, employers in the Russian Federation often prefer to use cheaper PPE to protect workers - although their actual effectiveness can be significantly lower.

Also, the preference for using PPE is influenced by the fact that their great versatility helped manufacturers and suppliers to unite by creating the PPE Association (ASIZ) in the early 2000s and lobbying their interests collectively and effectively ^[9] .

Organizational safeguards

To protect against harmful production factors, in cases where this exposure creates the risk of chronic occupational diseases due to excessive total exposure (dose), the dose can be reduced by reducing the duration of exposure ( protection by time ^[10] ). To protect people from ionizing radiation at nuclear power plants, fuel is loaded after removing the maximum number of employees at a safe distance from the reactor .

Use of personal protective equipment

When using personal protective equipment for the prevention of acute poisoning, chronic occupational diseases and other negative consequences of exposure to harmful factors, a number of problems arise that interfere with achieving the goal:

1. The use of PPE by workers does not eliminate or reduce the harmful factor itself, nor does it reduce the potential danger.
2. PPE itself, as a rule, has a negative impact on the well-being of the worker, and on his performance, and can cause new risks. For example, for PPE of respiratory organs, it was noted that it is unrealistic to achieve continuous wear of a respirator without forced air supply under the face during the entire shift (p. 24 ^[11] ). This is due to the increased content of carbon dioxide and reduced oxygen content in the inhaled air; additional resistance to breathing; discomfort due to the pressure of the mask on the face, etc. A narrowing of the field of view creates an increased danger when operating mobile equipment, and already in the middle of the 20th century it was noted that wearing an industrial gas mask increases the number of injuries - people stumble more often due to worse visibility down and forward ^[12] . The pressure of the noise-canceling headphones on the head, and the earbuds on the auditory canal, causes discomfort and possibly a headache, which can make prolonged continuous use of these PPEs difficult. PPE of the hearing organ interferes with adequately noticing and responding to warning signals, which can create a life threat. Wearing insulating suits in conditions of a heating microclimate prevents heat transfer by evaporation and convection, and enhances the body's overheating ^{[13] [14]} . At the same time, not constant use of PPE leads to such a decrease in the effect of their use that their sock can become meaningless.
   1. The effectiveness of PPE during their continuous use by a specific worker can significantly differ from that obtained during testing in the laboratory — to a lesser extent, and it is far from always constant. For example, when certifying elastomeric half-mask respirators with gas masks in the USA, the tester should not smell isoamyl acetate, performing various exercises in a room where the gas concentration exceeds the average threshold of smell perception by 25,000 times ^[15] . And the simultaneous measurements of the concentration of harmful substances under the mask and outside (in the breathing zone 25 cm from the face), carried out during work in the workplace , showed that the leakage of unfiltered air through the gaps between the mask and face can reach 45% ^[16] . Therefore, the use of laboratory measurements to assess the protection of workers in a production environment is unacceptable and dangerous. In addition, individual differences (anatomical and differences in the skills to correctly wear and correctly use PPE) lead to the fact that among the group of workers a subgroup may form, whose representatives will have reduced efficiency and significantly lower than expected ^{[17] [18]} . This creates an increased risk of developing occupational diseases among representatives of this subgroup, which is not compensated by the good protection of other workers. In the Russian Federation and other CIS countries, the replacement of gas filters is carried out mainly when there is a smell of toxic gas under the mask, which can lead to a belated replacement of the filter.
       

      Comparison of laboratory (during certification) and the real effectiveness of personal protective equipment for the hearing organ - inserts. Charts are based on Chapter 6 of the 1998 NIOSH Noise Protection Guidelines.
   2. According to the review ( section 1.5 ^[19] ), the real effectiveness of some types of PPE of the hearing organ, even with continuous use, can be lower than the declared value by manufacturers and suppliers on the basis of test results in laboratory conditions (during certification) by 4 times - on average (!).
   3. According to competent experts of the Scientific Research Institute of Occupational Medicine of the Russian Academy of Sciences , PPE from vibration - just like PPE of the respiratory and hearing organs ^[20] - can provide in practice insufficient protection ^[21] .
   4. In ^[22] , it was shown that PPE of the skin has features that also impede in practice obtaining those efficacy values ​​that are obtained during certification in the laboratory.
3. A lot of research has been done on the effects of PPE on performance and well-being. So, in the survey works ^{[23] [24]} it was shown that wearing a full-face mask can reduce performance by 1.35 ÷ 4.16 times, depending on the type of work and conditions at the workplace. This strongly encourages workers not to use RPDs in conditions of a slight excess of the MPC - they prevent them from working. objective data show that the wearing of PPE of the organ of hearing contributes to the growth of injuries due to difficulties in the perception of warning sound signals and communication difficulties ^{[25] [26]} .

Thus, there are many reasons for the non-continuous use of PPE; and an unpredictable decrease in their effectiveness with timely use. A sufficiently serious and extensive study of these causes was the reason for the attempt to ban the regular use of RPD in the USA in the 1970s ^[27] ; and became the basis for considering PPE to be the least reliable way to protect against harmful production factors.

According to the Constitution of the Russian Federation (Article 37, paragraph 3), all citizens have the right to work in safe conditions that meet sanitary and hygienic requirements. Similar provisions exist in the Labor Code of the Russian Federation (Chapter 34, Article 212); and in ILO Convention 148, ratified by the Russian Federation (Articles 9 and 10 ^[28] , the employer must first of all try to reduce the level of air pollution and noise, and only after that, if it is not possible to ensure compliance with the MPC and PDU , must organize the use of PPE).

In industrialized countries, the requirements of national law require the employer to use all possible ways to reduce air pollution to protect workers from air pollution, and only if their effectiveness is insufficient, use respiratory protective equipment ^[29] (p. 3 ^[11] ).

These requirements are general in nature, and their implementation should occur in conditions where for many decades, starting from 1936 ^[30] , the bulk of occupational diseases have not been detected and most of the accidents without a fatal outcome have not been recorded. The falsification of statistical indicators, and the lack of responsibility of the employer for the consequences of its actions (or inaction) in terms of ensuring safe and healthy working conditions, lead to the fact that, in spite of the requirements of the mentioned regulatory documents, and the ranking system of different protection methods, in practice they prefer to use PPE. And non-registration of occupational diseases and accidents contributes to the fact that even PPE is chosen so that they can technically be knowingly insufficiently effective. For example, in underground coal mining, the dust concentration may exceed 1 gram per m3 (more than 100 MPC), and the most ineffective of all RPES - half masks continue to be given to miners ; moreover, without checking whether they correspond to the person in shape.

For the prevention of occupational diseases and accidents, the Social Insurance Fund (FSS) allows the employer to use up to 20% of his contributions to the FSS - without distinguishing costs for improving working conditions; and PPE procurement costs. In practice, however, improving working conditions often requires more costs, more attention and labor than purchasing certified PPE - and employers mostly choose the easy way: According to the Social Insurance Fund, in 2014, 117 million rubles were spent on improving working conditions, and purchase PPE - 3,376 million rubles, ~ 29 times more. A similar ratio was observed in previous years. At the same time, in the Russian Federation there are no requirements established by law for the selection and organization of the use of PPE of the respiratory system, etc., which often leads to the purchase of certified but not adequate working conditions (by its design) and insufficiently reliable PPE ( for example, RPD ^{[20] [ 31]} ).

After the adoption of law 426-ФЗ, requiring a special assessment of working conditions, the employer was able to reduce the classes of working conditions (and, accordingly, deductions to the Social Insurance Fund , the Pension Fund and the Mandatory Health Insurance Fund , increase the duration of the work week, reduce paid holidays, etc. ) Thus, the state actually encourages the employer to use the most unreliable method of protection, and does not in any way control the choice of PPE. This leads to the fact that the real ranking of defense methods in the Russian Federation is opposite to the generally accepted in developed countries; and may be one of the reasons that the mortality rate of the working-age population of the Russian Federation is 4.5 times higher than in the European Union, and 1.5 times higher than in developing countries ^[32] .

• Hierarchy of prevention and control measures Мультиязычная википедия по технике безопасности и охране труда (статья на английском языке).
• How the hierarchy of control can help you fulfil your health and safety duties
• Canadian Centre for Occupational Health and Safety. OSH Answers Fact Sheets - Hazard Control (англ.) . http://www.ccohs.ca (08.05.2016). Дата обращения 8 мая 2016.
• Working at height - Hierarchy of control measures (англ.) . http://www.hse.gov.uk . Health and Safety Executive. Дата обращения 9 мая 2016.