Lesson A1: Using Substances Safely

Key Ideas     Unit Checklist

  Video Lesson

Chemicals help humans perform useful tasks. However, chemical substances must be handled safely. Labelling systems inform people of the potential hazards of different chemicals. Watch the two videos below to learn about the WHMIS chemical labelling system and how to handle chemicals safely during science experiments.

 
 

 
 

  Lesson A1: Using Substances Safely



Figure A.1.1.1 – The 'health hazard' WHMIS symbol.
Carcinogens

Cancer is a disease that happens when abnormal body cells grow out of control. This forms lumps, or tumours, inside the body. Sometimes, cancer cells form in the body after exposure to hazardous chemicals. Carcinogens are substances that cause cancer.
Reading and Materials for This Lesson

Science in Action 8
Reading: Pages 9–12

Materials:
No additional materials are needed for this lesson.

Carcinogenic chemicals can change healthy body cells into abnormal cells, which can grow into a dangerous tumor over time. Carcinogens can also trick normal body cells into reproducing faster, which increases the risk of mistakes when cells divide.

Sometimes people are exposed to carcinogens in the workplace. People who work in manufacturing, the trades, or agriculture often risk breathing in or touching dangerous chemicals. Exposure to carcinogens can be reduced by working with good ventilation and covering skin with protective clothing. Workers can avoid breathing in fine dust carcinogens by wearing a face mask. The WHMIS health hazard pictogram (Figure A.1.1.1) is used to label chemical carcinogens.

Figure A.1.1.2 – Wearing a face mask and gloves is a safety measure for handling hazardous carcinogens.
Figure A.1.1.3 – Some pesticides and herbicides are carcinogenic.

Figure A.1.1.4 – The corrosive WHMIS symbol labels corrosive substances.
Corrosive Substances

Corrosive substances can be helpful. Corrosive fluids are good at conducting electricity, which is why they are found in batteries. Corrosive fluids eat away at substances, which make them useful for removing unwanted chemical buildup. Corrosive oven cleaner is used to remove burnt grease from ovens. Corrosive drain cleaner breaks apart grease that clogs sink drains. Corrosive fluids are also used in chemical reactions to make useful products. Lye is a corrosive substance that is reacted with oil or fat to make soap.

While household corrosive substances are very useful, they must be handled with extreme care. They can burn skin, so always wear gloves when you work with fluids like oven or drain cleaner. Wearing safety glasses is also advisable, to prevent corrosives from accidentally splashing into your eyes. Good ventilation is also important, because breathing in corrosive fumes can burn your nasal and air passages.

Figure A.1.1.5 – Strong, concentrated acids are corrosive.
Figure A.1.1.6 – Corrosive substances burn through paper, metal, and skin.

Figure A.1.1.7 – You should wear gloves when handling corrosive household substances.
Figure A.1.1.8 – Protect your eyes and skin when working with corrosive chemicals.

 Watch More

Flesh Eating Acids

This video shows how corrosive acids eat through raw chicken drumsticks, which is similar to how acids would react with skin.



Compressed Gases

Figure A.1.1.9 – People with breathing problems carry cylinders of compressed oxygen gas.

Figure A.1.1.10 – WHMIS symbol for compressed gas.
Compressed gas containers are found in many homes and businesses. Aerosol spray cans contain compressed gases. Aerosol cans are found in many homes and businesses for substances such as hairspray, spray paint, and bug spray. Some useful gases are contained in large metal cylinders. People with breathing problems carry around compressed oxygen cylinders, with a hose connected from the tank to their nose. Scuba divers wear compressed oxygen tanks to breathe underwater. Barbecue fuel tanks contain compressed propane gas. Helium balloons are filled from compressed helium gas cylinders.

A compressed gas is very dangerous if its metal container is heated or punctured. If this occurs, gas can suddenly burst out of the container. The explosion of gas causes metal pieces of the container or the entire cylinder to fly uncontrollably. Always keep compressed gas containers away from heat and sparks.

Figure A.1.1.11 – Propane is a fuel gas that is compressed in a metal tank.
Figure A.1.1.12 – Aerosol cans contain compressed gas, which is used to force liquid spray out of the can.

 Watch More

The Dangers of Gases Under Pressure

What happens if a large compressed gas cylinder is punctured? Watch this video to find out.





Watch this news report to see what happens when aerosol cans are heated.



Safe Chemical Disposal

Dangerous household chemicals should not be thrown in the garbage or burned. Spilled or hidden chemicals are dangerous to other people who come into contact with them. Hazardous chemicals can also leak into to the environment if they are dumped in a landfill.

Most towns and cities have a special location where you can drop off dangerous chemicals, so they can be disposed of safely. Fluids such as paint, aerosol cans, and car fluids should be brought to these locations. Some hazardous chemicals are hidden inside products. For example, batteries contain corrosive acids. Compact fluorescent light bulbs contain toxic mercury vapour.

Do you know the location of your nearest chemical disposal?

Figure A.1.1.13 – Science laboratories must follow special rules for disposing waste chemicals.
Figure A.1.1.14 – Dangerous chemicals should not be thrown in the garbage.

 Watch More

Safe Chemical Disposal

This video explains how to properly dispose of batteries.





This video explains what kinds of hazardous chemicals should be brought to hazardous waste drop-off points in Calgary.

 
 

  Try It!

Household Chemical Inventory

What kinds of hazardous chemicals are around your home? Are they stored safely? What precautions should you take with those chemicals?

Try this activity to create an inventory of the dangerous chemicals in your home. 

Materials: 
  • Chemical inventory chart

  • Pencil

Do not handle any chemicals in this activity. Do not touch bottles of chemicals. You only need to LOOK at them.
If you need a bottle moved so you can read the label, ask an adult for assistance.
Download:

DOWNLOAD this document. It provides a space for you to write answers to questions later in this activity. It also provides a chart for you to record your observations.

Instructions: 
    1. Download the chemical inventory chart. You can print it and fill it in with a pencil, or fill it in digitally.


    2. Look around your home and garage for at least 5 hazardous chemicals. Remember to look only, DO NOT TOUCH. Some common ones to look for are cleaners, garden fluids, car fluids, and compressed gases.


    3. Fill out the chemical inventory chart for each chemical. List the chemical’s name and location. Look on the bottle for WHMIS symbols and warnings and list these hazards. Remember to look only, DO NOT TOUCH – if you need to move a bottle, get an adult to help you. Look on the bottle for any safety precautions and list these too.
      

    4. Take a careful look through your completed inventory chart, and use the chart to consider the following questions. Are all the dangerous chemicals in your home stored safely? They should be out of the reach of young children, and following the safety precautions. If not, are there changes you can make to ensure that all chemicals in your home are stored safely?



Questions: 

Think about the following questions very carefully. Then, type or write your answers. After you have your answers, click the questions for feedback.

All chemicals should be out of the reach of young children. It is important that anyone using the chemicals understands and follows all safety precautions.
The answer to this question depends on how the chemicals in your home are stored. In general, most homes can make improvements. Most importantly, all storage directions on chemical labels should be followed. Second, it’s a good idea to store chemicals where they cannot be tipped over. It’s also very important to periodically inspect chemical storage, to make sure there are no leaks.


Figure A.1.1.16 – The exploding bomb WHMIS symbol labels substances that react violently.

Figure A.1.1.15 – Many flammable substances (these can catch on fire) are also explosive.
Explosions

Explosions happen when a chemical reaction causes hot gases to form quickly. Hot gases have lots of energy, which means they expand suddenly at high speed. Explosions are dangerous because force from the gases causes other objects to fly uncontrollably. Fiery explosions result when flammable gases are sparked.

Gas barbecues have a risk of explosion. Propane gas in barbecue tanks is flammable. When a cloud of propane gas is lit, it will explode. For safety, if the flame on a barbecue goes out, turn off the propane tank and wait to let any gas clear the area before relighting. When not using the barbecue, always shut the entire tank off, not just the burners, so that propane doesn’t leak. When you turn off a lit barbecue, shut the propane tank first before turning off the burners. This clears propane out of the burner hoses.

Figure A.1.1.17 – Fire is dangerous in many ways, including causing explosions.
Figure A.1.1.18 – Flammable explosions create lots of heat energy.

 Watch More

Explosions

This cartoon explains the science behind explosions.





This news report shows what happens when propane barbecues explode.




Figure A.1.1.19 – These two satellite images, taken two days apart, show the Lac Mégantic fire in the lower right.
Lac Mégantic Disaster

In 2013, a disaster happened in the town of Lac Mégantic, Quebec. In the middle of the night, the brakes failed on a parked train. The train rolled downhill into the town at high speed and derailed. Many train cars were carrying flammable petroleum crude oil. Crude oil is volatile, which means it evaporates easily. Oil train cars were punctured on derailment, releasing volatile crude oil gases which sparked and exploded. The fire caused by the explosion burned for 2 days, destroyed much of Lac Mégantic’s downtown, and killed 47 people.

The Lac Mégantic derailment and explosion has led to many people questioning the safety of transporting hazardous substances like crude oil by railway through towns and cities. The alternative to oil transport on trains is pipelines, which some people consider to be safer.

 Watch More

Lac Mégantic Disaster

This video explains the events that led to the Lac Mégantic explosion.

 
 


This video shows videos and photos from the Lac Mégantic explosion.






  Make sure you have understood everything in this lesson. Use the Self-Check below, and the Self-Check & Lesson Review Tips  to guide your learning.

Unit A Lesson 1 Self-Check

Instructions


Complete the following 6 steps. Don't skip steps – if you do them in order, you will confirm your understanding of this lesson and create a study bank for the future.

  1. DOWNLOAD the self-check quiz by clicking here.

  2. ANSWER all the questions on the downloaded quiz in the spaces provided. Think carefully before typing your answers. Review this lesson if you need to. Save your quiz when you are done.

  3. COMPARE your answers with the suggested "Self-Check Quiz Answers" below. WAIT! You didn't skip step 2, did you? It's very important to carefully write out your own answers before checking the suggested answers.

  4. REVISE your quiz answers if you need to. If you answered all the questions correctly, you can skip this step. Revise means to change, fix, and add extra notes if you need to. This quiz is NOT FOR MARKS, so it is perfectly OK to correct any mistakes you made. This will make your self-check quiz an excellent study tool you can use later.

  5. SAVE your quiz to a folder on your computer, or to your Private Files. That way you will know where it is for later studying.

  6. CHECK with your teacher if you need to. If after completing all these steps you are still not sure about the questions or your answers, you should ask for more feedback from your teacher. To do this, post in the Course Questions Forum, or send your teacher an email. In either case, attach your completed quiz and ask; "Can you look at this quiz and give me some feedback please?" They will be happy to help you!

Be a Self-Check

Superhero!



Self-Check Quiz Answers

Click each of the suggested answers below, and carefully compare your answers to the suggested answers.

If you have not done the quiz yet – STOP – and go back to step 1 above. Do not look at the answers without first trying the questions.

 
Aerosol cans contain compressed gas. The oven cleaner should be listed with the compressed gas WHMIS symbol. Compressed gases should not be exposed to heat or sparks, and the can should not be punctured.

If oven cleaner burns skin, it is corrosive. It should be labelled with the corrosive WHMIS symbol. Skin contact with corrosive substances should be avoided, by wearing gloves. Corrosive substances should also be used in well-ventilated areas to prevent inhaling corrosive fumes.
A skull and crossbones WHMIS label indicates a toxic substance. Toxic substances can make people very sick or can cause death if ingested. You should move the bottle of cleaning bleach to a high location, out of the reach of small children who could accidentally drink it.
Batteries contain corrosive acid, which can leak if the battery heats up and explodes. This can cause harm to people or the environment. It is safer to take used batteries to a hazardous waste disposal location, where they can be disposed of safely.
Shaving cream cans are aerosol cans, which contain a compressed gas. If a shaving cream can is thrown into a fire, the gas inside heats up and will cause the can to explode. Sharp flying pieces of metal from the aerosol can cause serious injuries or death if they hit a person.
A box of injection needles should be labelled with a biohazardous WHMIS symbol. Needles that have been inside people’s bodies could be contaminated with bacteria or viruses.