INDUSTRIAL HAZARDS

HAZARD

It means anything with potential for producing an accident.

It is a term associated with a substance that is likelihood to cause an injury in a given environment or situation.

INDUSTRIAL HAZARD

Industrial hazard may be defined as any condition produced by industries that may cause injury or death to personnel or loss of product or property.

Industrial hazards are threats to people and life-support systems that arise from the mass production of goods and services.

Toxic and corrosive chemicals, fire, explosions and personnel falling into accidents are the major health and safety hazards encountered in the operations of chemical and pharmaceutical related industries.

ROUTES OF INDUSTRIAL HAZARDS ENTRY INTO THE BODY

There are three main routes by which hazardous chemicals entered the body:

Absorption through the respiratory tract through inhalation.

Absorption or injection through the skin or eyes.

Absorption through the digestive tract.

HAZARD CATEGORIES

Ø  Chemical Hazards

Ø  Gas Hazards

Ø  Dust Explosion

Ø  Fire and Explosion Hazards

Ø  Biological Hazards

CHEMICAL HAZARDS

Some chemicals have the potential to cause fires and explosions and other serious accidents. Chemical exposure may cause or contribute to many serious health effects such as heart diseases, central nervous system damage, kidney and lung damage, sterility, cancer, burns, and rashes. Chemicals may be found in solid, liquid, aerosol, or gas and vapor form.

The degree of danger varies according to the form of the chemical and the factors like,

ü  Its physical properties

ü  Its toxicity

ü  The way it is used

ü  The environment in which it is encountered.

Routes of entry - Inhalation, Ingestion, skin absorption.

Chemical agents can be classified into-

1) Metals - Lead, TEL, As, Hg, Cd, Ni , Co

2) Aromatic Hydrocarbons - Benzene, Toluene, phenol

3) Aliphatic Hydrocarbons - Methyl alcohol

4) Gases -

*  Simple asphyxiants : N₂, CH₄, CO₂

*  Chemical asphyxiants : CO, H₂S, HCN

* Irritant gases: Ammonia, SO₂, Cl₂

* Systemic poison: CS₂

Not all forms of a chemical pose a health hazard. For example, a lead pipe is not a significant health hazard. However, the lead can become a human health hazard if the pipe is welded, producing a lead dust or fumes. The dust or fumes can become inhaled, or it can leach into water and be ingested.

A chemical may be hazardous even in solid form. For example, individuals who are sensitized to nickel may develop dermatitis from skin contact with the metal.

Some solids are not a hazard alone but become hazardous when they come into contact with other chemicals.

MANAGEMENT OF OVER-EXPOSURE TO CHEMICALS

1. Removal from Exposure:

ü  Prompt removal of the person from the exposure site is the first step.

ü  Air respirators and lifelines are mandatory first aid.

2. Resuscitation:

ü  Resuscitation means restoration of life of one who is apparently dead (collapsed or shocked).

ü  Further supportive care should be provided as with any other medical emergency.

3. Decontamination:

ü  A victim whose skin or clothing has been contaminated requires immediate removal of garments and shoes. Then vigorous showering with soap and water, including attention to the fingernails and scalp is advised.

4. Symptomatic Treatment:

ü  Acute over-exposure may result in a variety of signs and symptoms that require general supportive medical management regardless of the specific agent. Examples include the control of convulsive seizures, treatment of bronchospasm etc.

TLV CONCEPT

Ø  Threshold Limit Value-Time Weighted Average (TLV-TWA):

Time-weighted average concentration for a normal 8-hour working day and a 40-hour working week, to which nearly all workers may be repeatedly exposed day after day, without adverse effect.

Ø Threshold Limit Value-Short Term Exposure Limit (TLV-STEL):

It is defined as a 15-minute, time-weighted average which should not be exceeded at any time during a working day, even if the 8-hour time-weighted average is within the TLV.

The workers should not be exposed to the substances more than these limits.

TLVs are only guidelines and are not intended as absolute boundaries between safe and dangerous concentrations.

Every occupational health professional should have a copy of the current TLVs.

HAZARDOUS GASES

Several volatile and flammable liquids are employed in chemical industries.

These liquids get vaporized when exposed to at or above room temperature causing air pollution.

The vapour gets ignited causing fire accidents and explosions. Further, they tend to spread rapidly into the surrounding area.

Result in loss of life and property. Hence, storage and handling of these hazardous gases need special attention to avoid hazards.

Combustible Gases

ü  Explosion hazard.

ü  Must maintain below lower explosive limit.

Toxic Gases

ü  Hazardous to human health.

ü  Employee exposure must be limited.

Oxygen Displacing Gases

ü  Indirect human health hazard.

ü  Deficiency of breathing oxygen.

HYDROGEN SULFIDE

H₂S in Air                   Toxic Symptoms

1 ppm                   Odor detected, irritation of respiratory tract

10 ppm                 Allowable for 8 hours exposure

20 ppm                 Protective equipment is necessary

100 ppm               Smell killed in 5 to 15 minutes.

May burn eyes and throat; coughing

500 ppm               Respiratory disturbances in 2 to 15 minutes.

Coughing, collapse & unconsciousness

1,000 ppm            immediate unconsciousness,

Brain damage may result unless rescued promptly.

Death in 3 to 5minutes.

OXYGEN DEFICIENCY

Oxygen Symptoms Developed,

20.9%                Normal oxygen concentration in air

15 - 19%            Decreased ability to work strenuously

12 - 14%           Respiration increases in exertion, pulse up, impaired coordination, perception                      & judgment

8 - 10%              Mental failure, fainting, unconsciousness, blueness of lips, nausea & vomiting

6 - 8%                 8 min, 100% fatal; 6min, 50% fatal; 4 - 5min, recovery with treatment

4 - 6%                Coma in 40 seconds, convulsions, respiration ceases, death.

HAZARDOUS GASES MANAGEMENT

Compressed gases are filled in cylinders and transported to the place of use. The important precautions to be followed are given below:

1.   Cylinders should not be dropped or permitted to strike against each other.

2. Special and standard tools should be used on valves. Normally these are provided by manufacturers.

4. Cylinders should be protected against extremities of weather, particularly against excessive rise in the temperature.

5. Cylinders (received) should bear a conspicuous standard label indicating the kind of gas. The colour of the label shows whether gas is inflammable, corrosive or inert.

6. Full cylinders should be separated from empty cylinders.

GAS SENSOR PLACEMENT

Ø  Place sensors close to possible gas source.

Ø  Place sensors in areas where gas might accumulate.

Ø  Place toxic gas and oxygen deficiency sensors in the “breathing zone”.

Ø  Consider accessibility and maintenance issues.

GAS WEIGHT IN RELATION TO AIR

Carbon Monoxide            Slightly Lighter

Ethylene                            Slightly Lighter

Ammonia                          Lighter

Methane                            Lighter

Hydrogen                          Lighter

Butane                               Heavier

Chlorine                            Heavier

Heptane                             Heavier

Ethane                               Slightly Heavier

DUSTS EXPLOSION

Dust means, if the maximum particle size of the solids in the mixture is 500 mm.

Dust explosion is a rapid combustion of a dust cloud. During the process, heat and reaction products are evolved. The required oxygen for combustion is mostly supplied by air.

If iron or stone pieces get into the disintegrator or grinding mill, sparks are emitted, which may bring about explosion with some easily combustible materials.

It has been found that in pharmaceutical industry, dust of starch and dextrin besides organic substances are extremely hazardous.

FACTORS IMPACTING A DUST EXPLOSION

1. Particle size
2. Chemical properties of a dust
3. Moisture content
4. Cloud dispersion

COMBUSTION PRINCIPLES

Fire is a rapid oxidation process with the evolution of light and heat in varying intensities.

2C + O₂                            2CO

DUSTS MANAGEMENT

1. Avoiding the development of explosive mixtures: Dust should not be accumulated at a place. Removed from the site as soon as it forms.
2. Replacing the atmospheric oxygen by inert gas or using inert dust: This process is also known as inerting. Explosion dusts can be changed into mixture by the addition of inert dust such as rock salt and sodium sulphate, so that dust is diluted to a level less than its lower limit of explosive range.

3. Preventing the occurrence of effective ignition source: Some of the ignition sources are welding, smoking, cutting, and mechanically generated sparks and the resulting hot sources. The premises must be kept very clean, eliminating all sources of ignition.

CONTROL OF DUST EXPLOSION

In pharmaceutical industry, dust is controlled by three methods.

ü  Filtration

ü  Inertial separation

ü  Electrostatic precipitation

FIRE AND EXPLOSION HAZARDS

Spontaneous combustion and non-explosion proof electrical equipment is the potential ignition source.

The severity of the burns depends on the intensity of the fire and the explosion time.

Fire occurs in the industry more frequently than explosions and toxic release, although the consequences in terms of loss of life are generally less. So, fire might be less hazardous.

CONTROL OF FIRE AND EXPLOSION

1. Careful plant layout and judicious choice of constructional materials can reduce fire and explosion hazards.
2. Fire resistance brick-walls can limit the effects of an explosion.
3. The roof is designed to lift easily under an explosive force.
4. Possible sources of fire are reduced by eliminating the unnecessary ignition sources such as flames, spark, smoking, welding etc.
5. The installation of sufficient fire alarms, temperature alarms, fire-fighting equipment and sprinkler systems must be specified.

Ø   Building Construction:

Building should be constructed such that fire can’t be separated from one building to another. When combustible construction is involved, firewall cutoffs should be provided.

Ø  Exit Points:

The exit points of adequate capacity should be provided so as to enable the employees to reach a place of safety outside the building, in case of fire.

Ø   Fire Alarm Equipment:

Fire alarm systems are placed in conspicuous locations in all parts of the plant for promptly notifying the fire brigade and for exit of employees.

Ø   Sprinkler Systems:

Automatic sprinkler is a device for discharging water automatically on a fire.

Ø   Safety and Fire Protection Organization:

A central committee composed of the plant manager as permanent chairman and safety and fire protection supervisor as permanent secretary.

Ø   Fire Extinguishers:

Fire extinguishers are installed inside hose. These are designed for extinguishing the incipient fires. The incipient fires are divided into three categories,

Class A fires: These fires are originated from ordinary combustible materials. These fires are controlled using water which produces quenching and cooling effects.

Class B fires: These fires are originated from oil’s, greases, flammable liquids etc. The extinguishing agent should produce a blanketing or smoothening effect.

Class C fires: These fires are originated in electrical equipment. The extinguishing agent produces a non-conducting property.

BIOLOGICAL HAZARD

This can include medical waste or samples of a microorganism, virus or toxin that can impact human health.

It can also include substances harmful to animals.

Ø  Biological hazards cause a lot number of diseases like,

Brucellosis: it usually occurs in dairy farm workers. Symptoms - fever, arthritis, and enlarged spleen etc.,

Byssinosis: It usually found in textile industries workers due to inhalation of the cotton fibre, dust over long period of time. Symptoms - Cough breathlessness, slight fever and bronchitis.

Others are baggosis and locomotor disorder.

PREVENTIVE MEASURES

Ø  All the workers who come in direct contact with the products including raw materials shall undergo periodic health check up.

Ø  Personal protection of workers should be provided with masks or respirators with oxygen or air supply.

Ø  The manufacturer should also provide,

ü  Adequate first aid facilities.

ü  Initial medical examination & periodic medical health check up.

ü  Facility for vaccination.

ü  The manufacturing area should be maintained clean.

ü  A routine sanitation programme shall be drawn up & observed.

INDUSTRIAL SAFETY

Identification of the hazards and employing the protective measures to control the hazards are important to protect the people from their consequences.

OBJECTIVES- SAFETY MANAGEMENT

Ø  Safety of men at work and in the vicinity of hazards.

Ø  Effective rescue and treatment of casualties.

Ø  Mitigating the severeness of Disaster first and ultimately to control the whole situation.

Ø  Casualty identification, classification and safe transportation to Trauma Centre or Hospital.

Ø  Providing factual information to authorities coordinating the operations to avoid contradiction and confusion.

THE FIRST STAGE OF SAFETY ASSESSMENT

In a process plant essentially consists of three steps:

1. Identifying the hazard.
2. Estimating the effects or   consequences of the hazard.
3. Determining probability or likelihood of occurrence of hazardous event.

THE NEXT STEP OF SAFETY ASSESSMENT

To determine whether effects of the consequence and the probability of occurrence of the hazard is within the acceptable limit or not.

EMPLOYER RESPONSIBILITIES

ü  Identify and list hazardous chemicals in their workplaces.

ü  Obtain Material Safety Data Sheets (MSDSs) and labels for each hazardous chemical, if not provided by the manufacturer, importer, or distributor.

ü  Implement a written Hazard program, including labels, MSDSs, and employee training.

ü  Communicate hazard information to employees through labels, MSDSs, and formal training programs.

HOW CAN WORKPLACE HAZARDS BE MINIMIZED?

ü  The first step in minimizing workplace hazards is to perform a thorough hazard assessment.

ü  Employers can rely on the evaluations performed by the manufacturers or importers to establish the hazards of the chemicals they use.

Ø  This information is obtained from MSDSs and labels.

WHY IS A WRITTEN PROGRAM REQUIRED?

Ensures that all employers receive the information they need to inform and train their employees.

It provides necessary hazard information to employees.

HOW MUST CHEMICALS BE LABELED?

Each container of Hazardous chemical entering the workshop must be labeled or marked with:

ü  Identity of the chemical

ü  Appropriate hazard warnings

ü  Name and address of the responsible  party

CONTAINER LABELING IN THE WORKPLACE

The hazard warning can be any type of message, picture, or symbol that provides information on the hazards of the chemical(s) and the targeted organs affected, if applicable.

Labels must be legible, in English (plus other languages, if desired), and prominently displayed.

MATERIAL SAFETY DATA SHEETS

It is prepared by the chemical manufacturer or importer and describes:

ü  Physical hazards, such as fire and explosion.

ü  Health hazards, such as signs of exposure.

ü  Routes of exposure.

ü  Precautions for safe handling and use.

ü  Emergency and first-aid procedures.

ü  Control measures.

It must be in English and include information regarding the specific chemical identity and common names.

It must provide information about the:

ü  Physical and chemical characteristics

ü  Health effects

ü  Exposure limits

ü  Carcinogenicity (cancer-causing)

ü  Identification (name, address, and telephone number) of the organization responsible for preparing the sheet

It must be readily accessible to employees in their work area.

MSDSs have no prescribed format.

If no MSDS has been received for a hazardous chemical, employer must contact the supplier, manufacturer, or importer to obtain one and maintain a record of the contact.

TRAINING

Training is required for employees who are exposed to hazardous chemicals in their work area:

ü  At the time of initial assignment.

ü  Whenever a new hazard is introduced into their work area.

WHAT TRAINING IS NEEDED TO PROTECT WORKERS?

Explanation of the Safety program, including information on labels, MSDSs, and how to obtain and use available hazard information.

Hazards of chemicals.

Protective measures such as engineering controls, work practices.

How to detect the presence or release of a hazardous chemical (using monitoring devices, observation, or smell)