Assessing OSH risks at intermitten plastic recycling facilities

1. INTRODUCTION

Currently, plastic recycling by mechanical methods is very popular in Vietnam as well as in the world, because mechanical recycling is easy to implement and has high recycling potential. However, this activity is still highly spontaneous in craft villages. Although there are still facilities with automatic and modern scale and production lines, there are still many establishments with intermitten manual lines using old and outdated machines. Some of the main stages in intermittent plastic recycling (washing, preliminary shredding, crushing, etc.) have high and very-high risks. This article presents the results of the occupational health and safety (OSH) risk assessment (RA) and proposes some control measures in small and manual plastic recycling facilities in Vietnam.

2- RESEARCH METHODS

– Data collection method: Survey method, interviewing employees and employers, measuring environmental parameters at plastic recycling facilities.

– Hazard identification method: It is combined with a number of hazard identification methods such as checklists, job safety analysis, combined with direct interviews with workers as well as employers of facilities manufacturing raw materials from recycled plastic.

– Risk assessment method for occupational safety hazards: Using a qualitative risk assessment method for occupational safety hazards, the risk matrix is presented in Table 1.

     Table 1. Labor safety risk matrix

– Risk assessment for occupational health hazards: Using a semi-quantitative risk assessment method. Based on the “VNIOSH Method – 2017” and current QCVN/BYT standards on occupational hygiene, occupational health risk assessment methods used for typical health hazards in plastic recycling are: microclimate, dust, noise , chemicals, these parameters are measured at factories or workshops that produce plastic beads from waste plastic. The process of risk assessment is performed based on the measured values and referenced with the corresponding value in the above method.

3. RESULTS OF RISK ASSESSMENT AND CONTROL MEASURES

Surveys at manual plastic recycling facilities show that there are many hazards that need to be assessed and controlled. However, at each stage, there are many other potential hazards that need to be specifically assessed. The following are the results of the risk assessment at some key stages according to the steps in the process of producing recycled plastic beads.

– At the raw material warehouse: At most manual plastic recycling facilities, the raw material warehouse is placed in the same area with the production workshop, so the main hazards are fire and explosion, residual organic matter on the packaging, microorganisms, tripping. fall bruised limbs, muscle aches, microclimate…. The reason is that the raw materials were collected in the market and dumped in a mess (under the influence of summer heat in the Northern region, the raw materials released foul smell etc….), electrical wires running on the workshop floor, wetness, short-circuited and lead to fire and explosion…. Risk assessment results show that there is a risk of fire and explosion, discomfort, allergies, rashes caused by microorganisms, molds/substances. organic matter, high temperature are high-risk hazards. The hazards of muscle fatigue, falls are medium-risk.

– Pre-washing/washing materials: Hazards such as injury due to clamped by machinery, sharp objects stabbing hands, slippery, tripping, allergies, rashes, caustic hand and foot skin caused by microorganisms, fungi Mold, organic matters left in the packaging combined with moisture causing a very uncomfortable feeling, electrical cords running on wet ground prone to electric shock are hazards that are assessed as high risk. In addition, the washing machine is a single machine, the worker inserts the materials into the machine and this work is done in batches, so there will be muscle pain, this hazard is assessed as medium-risk. .

– Drying raw materials outdoors: Workers have to carry raw materials after washing them to dry outdoors and have to pluck them to dry between hot and humid summer temperatures, workers are prone to heatstroke, heatstroke thus this stage is deemed high-risk. This stage depends very much on the weather, the hazards of microclimate, ergonomics etc… and are assessed as high risk.

– Preliminary hashing of raw materials: This stage appears in establishments that buy raw materials in the form of tarpaulins, or bavia from tarpaulin factories… of large size, so preliminary hashing is required. The main hazard is rolling, clamping, cutting into the hand which is assessed as very high risk. The risk of electric shock, working posture is also high risk in this stage.

– Loading ingredients into blender/crusher: A common hazard is clamping, falling into the blender/crusher. The main reason is the improper arrangement of materials and equipment in the factory. Raw materials are piled high, bumpy, higher than the location of the grinder/crusher, workers standing on the pile of ingredients to put them into the grinder/crusher and sometimes they are careless and use their feet to step on the ingredients. machine…, slipping and falling in the grinder/crusher in operation…. Risk assessment results considered this stage highly-risky. In addition, at this stage, there are hazards such as tripping, egonomi is assessed as high risk.

– Loading material for heating stage: After crushedraw materials are loaded by workers into the heater, at this stage the main danger is muscle, bone and joint pain and is assessed as having medium risk.

– Monitoring the spinning heating process: When the material is heated to a certain temperature (depending on the type of plastic), the plastic will melt, during the extrusion heating process, there will be gas explosion, plastic drops liquid, hot burns workers occurs frequently. This is also a common hazard in automatic recycling facilities. VOCs (volatile organic compounds) are detected in this process. The factory is cluttered, and the power cord runs on the floor of the factory, so workers are prone to slips, tripping on wires, objects and edges of equipment. The risk assessment results for these hazards are high-risk. VKH hazards are assessed as very high risk on summer days in the North, noise is of medium risk.

– Supervision of fiber shaping cooling process: Workers have bruised limbs due to tripping on the edge of the base of this unit, which is a common hazard and is considered high-risk.

– Granulating-Packing plastic granules: At this stage, there is a risk of microclimate and ergonomic, workers have to carry bags of plastic beads with a weight of 25kg. The risk assessment results for hazards are high risk. Slip hazards are medium risk.

– Maintenance/repair/cleaning of machinery: At this stage, there are many hazards that are assessed as high risk such as sharp objects in the hands, clamps on equipment, high falls, chemicals/organic substances, etc. organism, microorganism.

General assessment and control measures

Most of the production stages of recycled plastic pellets have working positions that are rated as high-risk. In the stages of preliminary chopping, feeding the grinder/crusher, there are many hazards such as sharp objects hitting the hands or clamping that are very risky. During the fiber extrusion heating process, the phenomenon of gas explosion, which shoots liquid plastic droplets, often causes burns to workers.

The occupational health hazards are expressed through parameters such as microorganism, noise, dust, organic vapors…. Measurement results show that most of the production stages in these facilities have temperature within the range of 32-37oC, all exceed the allowable limit according to standard QCVN 26:2016/BYT, especially in the spinning heating stages, the temperature rises from 36-37oC and is considered to have high level of risk. Noise is mainly due to crude, old and outdated machinery, measured at many stages with a value greater than 90 dB. According to VNIOSH – 2017 method, noise is assessed at medium risk. Toxic VOCs were detected in plastic recycling facilities, particularly in the granulation (heating, spinning, granulating) areas but at low levels and assessed as an acceptable risk. . However, it is necessary to have control methods for these factors because they can enter the body through the respiratory tract, digestive tract, skin and accumulate in the employee’s body up to a certain time, which can develop into diseases. Organic matter left in the packaging is also a hazard that needs to be controlled (unpleasant smell…).

Occupational safety hazards need to be controlled and preventive measures should be immediately implemented such as redesign of power lines, rearrangement of machinery locations, warehouses, factories… and basic measures such as administrative control methods (compliance with 5S rules, signs…). The safe working rules, especially the safe implementation process in the grinding/grinding stage, the fiber heating stage, it is necessary to have studies to avoid the phenomenon of plastic explosions flying into workers, leading to injury. burn. Occupational health hazards need to be taken measures to strengthen the mechanism to collect, absorb toxic gas, ventilate dust, and shield to isolate noise…. Employees meed to be trained in OSH and fully equipped with equipment. personal protective equipment. It is strictly forbidden to eat and drink in the factory. In addition, these facilities need to supplement or strengthen the waste and wastewater treatment unit after the recycling process.

CONCLUDE

Risk assessments in manual plastic recycling facilities have identified many high-risk, very high-risk occupational safety hazards. The factory layout is not reasonable and scientific, so there are many great dangers. Occupational health hazards in which physical hazards such as noise are also at medium risk require mitigation measures. Toxic VOC gas is only at detectable levels, but it is also a hazard that needs attention and a control plan because it is a possible carcinogen if exposed for a long time. Some control measures such as administrative control measures, occupational safety and health training, industrial sustainable development, etc. are easy and effective to be implemented and need to be implemented immediately.

Dr. Nguyen Thịi Thu Thuy

VNNIOSH

(Source: Vnniosh.vn)