CHEMICAL SAFETY IN SCHOOLS/COLLEGES – REDUCING

RISKS TO YOUNG PEOPLES

Dr. M.K.N. YenkieProfessor of Chemistry

Registrar – RTM Nagpur University

Director - Laxminarayan Institute of Technology

R.T.M. Nagpur University

Nagpur - 440 033

2

“Halogens”

Periodic Table of the Elements

• Elements are arranged by atomic number

• Elements in the same vertical columns have similar properties “Alkali Metals”

CHEMICALS

• Chemicals have invaded all sectors of human life

• Possess inherent dangers

Chemistry has the potential to solve the mysteries of life. However, NO CHEMICAL IS TOTALLY SAFE OR NON HAZARDOUS ONLY SAFE WAY OF HANDLING THEM

Dangers associated with chemicals

• Storing raw material

• Production site

• Storing products

• Transport

Lab Chemicals

• Acids and Bases

• Permanganate

• Salts

• Burners

• H2S

Chemicals used at Home• Acids and Bases

• Permanganate

• Salts

• Burners

• Bleaching powder

• Insecticides

• Protection of grains

Ammonia

• Anhydrous Ammonia– pH>12; (household ammonia pH < 12)

– Wide industrial use• Plastics, fertilizer, explosives

– Irritating, corrosive; causes necrosis, severe pain– Serious injury to eyes, lungs, skin, GI tract

• Management– Remove from exposure, decontaminate– Symptomatic; maintain airway

8

Ammonia

Chemical Formula: NH3 CAS# 7664-41-7 UN#1005 ISCS: 0414

Physical State: Colorless , compressed liquefied gas, with pungent odor

Physical Properties• Boiling Point: -33°C• Relative Density: 0.7 at -33°C• Vapor Density: 0.59 • Solubility in water 54 g/100mL, 20°C• Vapor Pressure, 1013 kPa at 26°C• Explosive Limits, vol% in air: 15-28• Auto-ignition temperature: 651°C

Fire and Explosion: Flammable; gas/air mixtures are explosive.

Health Hazards Corrosive to eyes, skin, respiratory tract. Inhalation results in burning sensation, labored breathing; skin burns; contact with liquid causes frostbite; severe deep burns to eyes; harmful concentration of this gas in air will be reached very quickly on loss of containment

Route of Exposure: Inhalation

Chemical Dangers: Shock sensitive compounds are formed with mercury, silver and gold oxides. The substance is a strong base; it reacts violently with acid and is corrosive. Reacts violently with strong oxidants and halogens. Attacks copper, aluminum, zinc and their alloys. Dissolves in water evolving heat.

Physical Dangers: The gas is lighter than air.

Use: Manufacture of nitric acid, explosives, synthetic fibers, and fertilizers.

• Class 1 Explosives• Class 2 Compressed Gases• Class 3 Flammable Liquids• Class 4 Flammable Solids• Class 5 Oxidizers• Class 6 Poisons• Class 7 Radiological• Class 8 Corrosives

• Class 9 Other Regulated Materials

UN Classification Hazard Classes and Divisions

NINE HAZARD CLASSES AND SUBDIVISIONS

Class 1 – Explosives

Mass explosion that affects almost the entire load

Class 2 – Gases

2

FLAMMABLE GAS

2

NON-FLAMMABLE

GAS

POISON

GAS

2

Class 3 – Flammable Liquids

FLAMMABLE

3

Class 4.1 – Flammable Solids

FlammableSolid

4

Class 4.2 – Spontaneously Combustible Materials

SPONTANEOUSLYCOMBUSTIBLE

4

Class 4.3 – Dangerous When Wet

Dangerous when Wet

4

Class 5.1 – Oxidizers

Oxidizer

5.1

Class 5.2 – Organic Peroxides

OrganicPeroxide

5.2

Class 6.1 – Poison, Inhalation Hazard

Poison

6.1

Class 6.2 – Biohazard

Class 7 – Radioactive

Radioactive

Class 8 – Corrosive

Corrosive

Class 9 - Miscellaneous Hazardous Materials

OrOther Regulated Materials(ORM)

Aerosol / Infectivity Relationship

18-20

15-18

7-12

4-6(bronchioles)

1-5 (alveoli)

Infection Severity

Particle Size (Micron, Mass

Median Diameter)

The ideal aerosol contains a homogeneous

population of 2 or 3 micron

particulates that contain one or more

viable organisms

Maximum human respiratory infection is

a particle that falls within the 1 to 5

micron size

Less Severe

More Severe

Occupational and environmental airways diseases

Silicosis

Lake Nyos Volcano

• Lake Nyos was formed due to volcanic eruption about 400 years ago. It is 5,900 feet across and 682 feet deep.

• Lake Nyos is compositionally stratified with layers that do not mix, with fresh water in the upper 50 meters and heavier sodium and carbon dioxide (CO2) rich water below that. It is one of only three known lakes to be saturated with CO2 in this way.

• Approximately 50 miles below the lake resides a pool of magma, which charges the water of Lake Nyos with an estimated 90 million tons of CO2.

• The lake waters are held in place by a natural dam composed of volcanic rock.

Disaster Strikes• At 9:30 pm on August 21, 1986 - eruption Lake Nyos

triggered sudden release of 1.6 million tons of CO2..

• The cloud of CO2 rose at nearly 62 miles per hour.

• Carbon dioxide, 1.5 times as dense as air, cloud hug the ground and descend down the valley. The 164 ft thick cloud traveled downward at a rate of 12-31 mph.

• killed over 1700 people, thousands of cattle, birds and animals.

• The bodies of those that died were generally devoid of trauma, suddenly fallen asleep and died from asphyxiation.

• Following the disaster, the lake was dubbed the “Deadliest Lake” by the Guinness World Records in 2008.

The Science Behind the Disaster• It is important to remember that Lake Nyos is

thermally stratified- with layers of warm, less dense water near the surface floating on the colder, denser waters near the lake’s bottom.

• Over time, the lowest levels of the lake become more and more saturated with gas. And eventually, when they reach 100% saturation, the CO2 rich gas can bubble spontaneously out of the lake , creating a foaming column of carbonated water.

• This eruption can be triggered by an event such as a landslide, earthquake, violent storm, or other disturbance of the water.

• The normal blue waters of the lake turned a deep red after the outgassing, due to iron-rich water from the deep rising to the surface and becoming oxidized by the air.

• The level of the lake dropped about a meter, representing the volume of gas released

Tin:Tin:allotropic forms:

-Sn“grey tin” 13.2°C

-Sn“white tin”161°C-Sn 232°C Sn(l)

-Sn: typical metallic properties: conductor, ductilecrystal structure: body centered tetragonal

d = 7.29 g/cm3

-Sn : semiconductor, non-ductilecrystal structure: diamond cubic

d = 5.77 g/cm3

Tin PestTin Pest (tin disease, tin plague, devil´s disease):

first reported: 1851; responsible for the disintegration of tin dishes, organ pipes, …

is the product of the conversion: -Sn -Sn at T < 13.2 °C

volume change leads to the total disintegration of the sample

Tin PestTin Pest

without tin pest

complete disintegrated

All for want of a buttonTin has two allotropic forms : α (gray tin ) β

(white tin)White tin is shiny metal and stable at room

temperature but slowly transforms into gray tin below 13 oC. This weakens the metal and makes it crumble (tin disease).

In June 1812, Napoleon’s mighty army, some 600,000 strong marched into Russia, but by early December his forces were reduced to fewer than 10,000 men. An intriguing theory for Napoleon’s defeat has to do with tin buttons on his soldiers’ coats! The soldiers were probably more busy holding their coats together with their hands than carrying weapons.

Mars Surveyor Program 1999

Mars Climate Orbiter Mars Polar Lander

Mars Surveyor Program 1999 (Orbiter and Lander)

• Mission: To study Martian weather, climate, atmosphere, evidence of life, …– $327.6 million total – MCO lost due to navigation error

• Launch Dec 11, 1998 – Lost Sep 23, 1999

• Failure is attributed to the failure of NASA’s system engineering process. The process did not specify the system of measurements to be used in the project (English vs. Metric)

– MPL never called home! • Launch Jan 3, 1999 – Lost: Dec 3, 1999

Mars Surveyor Program 1999 (Orbiter and Lander)

In December 1998 NASA launched the 125 Million$ Mars climate Orbiter. After 416 Million mile jorney, the space craft was supposed to go into Mars’ orbit on Sept. 23, 1999. Instead it entered Mars’ atmosphere about 100 km (62 Mile) lower than planned and was destroyed by heat.

The error occurred due to the failure to convert English Measurement units into metric unit.

Engineers at Lockheed Martin Corporation who built the spacecraft specified its thrust in pounds. Scientists at NASA,s Jet Propulsion Laboratory, on the other hand assumed that thrust data they received were in metric units, as Newton.

Conversion between Pound and Newton

1 Pound is the force due to gravitational attraction on an object of that mass. 1 lb = 0.4536 kg,

from Newton’s second law : force = mass x accelaration

= 0.4536 kg x 9.81 m/s2

= 4.45 kg. m/s2

= 4.45 N

Because 1 N = 1 kg m/s2, instead of converting one pound of force to 4.45 N, the scientists treated it as 1 N.

this considerable small thrust resulted in a lower orbit and the ultimate destruction of the spacecraft.

The Patriot Missile Failure

• February 25, 1991 – Gulf War – Dharan, Saudi Arabia

• American Patriot Missile battery failed to track and intercept an incoming Iraqi Scud missile

– 28 US soldiers killed, 100+ injured • Software bug: inaccurate calculation of the time

since boot due to computer arithmetic errors

Minamata, Japan Mercury Poisoning Disaster

• The Minamata Disaster was more of an on going mass poisoning than a single catastrophe.– It was caused by the

Chisso Corparation in the city of Minamata on Kyushu Island, Japan.

– They dumped organic mercury off the coast of Minamata for over 3 decades.

– There have been over 3,000 victims. Many of them lost their lives and others suffered from physical deformities.

http://wi.water.usgs.gov/pubs/FS-216-95/mercury.pg3.pdf

• Bioaccumulation occurs when an organism takes up contaminants more quickly that it eliminates them

• Biomagnification is an incremental increase in the concentration of a contaminant at each level of the food chain

http://wi.water.usgs.gov/pubs/FS-216-95/mercury.pg2.pdf

Disaster Continued

• Chisso knew the mercury they were dumping was contaminating the water, but did nothing.– The poisoned waters created

a ripple effect; killing marine life, birds, domestic animals and humans.

– Villagers that complained were measly compensated or threatened.

• The Chisso Corporation stopped poisoning the waters in 1968 only when the method of mercury production became outdated.

Signs and Symptoms

• Victims were diagnosed with a degenerative nerve condition.

• Signs included: – Numbness of the limbs and lips – Slurred speech and blurred

vision– Brain damage– Loss of consciousness– Involuntary movements– Symptoms of Turrets

Syndrome (uncontrolled shouting)

– Physical Deformities

Images Continued

BHOPAL DISASTERTotal breakdown of essential safety provisions and negligence of the authorities According to safety norms MIC tanks should be protected by dry Nitrogen

blanket and kept at 0 oC by refrigeration. Refrigeration unit was shut down since June 1984, gas was at 15-20 oC. MIC reacts violently with water and also undergoes polumerisation in

presence of catalysts like Fe, Cu, Zn (both processes highly exothermic) MIC is always associated with 2% Phosgene (TLV 0.1 ppm) Leakage detected at 11.30 p.m., Temperature gauge showed 25 oC, pressure

build up above 55 psi and the safety valve opened. MIC gushed out from 120 ft. high stack, water jet failed to reach that height,

vent gas scrubber which neutralizes MIC with caustic soda was out of order. Factory turned on the public siren at 1 am for a few minutes only, people got

up not due to siren but due to irritation caused by gas. For about two hours the safety valve remained open and then reseated as the

tank pressure dropped below 40 psi.

Advent of a new age 20th March 1995 Tokyo Metrorail Morning rush hour between 8.09 - 8.13 a.m. Radical group ‘AUM SHINRIKYO’ placed five plastic

pouches of lethal nerve agent SARIN and punctured them

11 immediate deaths and 5500 injured More than 26 stations closed for three weeks [Aum

Shinrikyo was also in possession of germs Yersinia Pestis which causes Plaque and large stockpile of SARIN]

Tokyo Chemical Incident20 March 1995: Sarin attack in Tokyo by the Aum Shinrikyo

Some useful chemicals may be abused!

• Ammonium nitrate most important fertilizer in the world is ranked 15th among industrial chemicals produced.

• UNFORTUNATELY IT IS A POWERFUL EXPLOSIVE!

Phosgene

• At high concentrations:– Irritates eyes, nose, upper airways; possible laryngospasm

• Toxic to lungs by inhalation

• Carbonyl group damages alveolar-capillary membrane

• Non-cardiac pulmonary edema: onset 2 to 12 hours– Dyspnea, cough with sputum

• Management of non-cardiac pulmonary edema– Hypoxia, fluid loss; requires pulmonary care, careful fluid

replacement

• ABSOLUTE REST POST-EXPOSURE

Cl

C = O

Cl

Nerve Agent Medical Treatment

• Atropine– Dries secretions; relaxes smooth muscles– Given IV, IM, ET

• No effect on pupils

• No effect on skeletal muscles

Nerve AgentTreatment

• Starting dose - 2 mg• Maximum cumulative dose - 20 – 30 mg

– Insecticide poisoning requires much more• Side effects in normal people

– Mydriasis – Blurred vision– Tachycardia– Decreased secretions and sweating

Nerve AgentMedical Treatment

• Atropine - How much to give?– Until secretions are drying or dry– Until ventilation is “easy”– Do not rely on heart rate or pupil size

Nerve AgentMedical Treatment

• Pralidoxime Chloride (2PAM-Cl)– Remove nerve agent from AChE

– 1 gram slowly (20-30 minutes) in IV infusion• Hypertension with

rapid infusion

– No effects on

glands, smooth muscle AChEAChE 2-PAMCl

Nerve AgentNerve Agent

Any Questions

CAUSES OF DISASTERS

HUMAN FACTORS : The causes of failure can be classified as:

Insufficient knowledge 36 %Underestimation of influence16 % Ignorance, Carelessness, negligence

14 %Forgetfulness, error 13 %Relying upon others without sufficient control 9 %Nonprecise definition of responsibilities 1 %Bad quality 1 %Other 3 %

FACTORS AFFECTING CW

• AIR MOVEMENT

• TEMPERATURE

• COLD WEATHER

• RAIN AND HUMIDITY

• TERRAIN

NERVE AGENTS - ANTODOTES & TREATMENT AFTER EXPOSURE

• Atropine and pralidoxime chloride (autoinjectors provided)

• Diazepam (anticonvulsant drug)

• 4 Steps to management

• Decontamination• Ventilation• Antidotes• Supportive therapy

HARASSING AGENTS - ANTIDOTES & TREATMENT

• Relocate to fresh air

• Through washing of exposed eyes and skin with water

• Effects gradually dissipate within 15-30 minutes of departure from contaminated area

PROTECTION AGAINST CW

• Use respirator• Whole body should be protected with

suitable anti-gas clothing

• In the absence of proper respirator breathing through a towel of large handkerchief saturated with alkaline solution gives a certain degree of protection