Spring is when we start to do my home repairs. As we paint, clean, and maintain our lawns, we’re often unaware of the safety hazards from the chemicals we use.

A couple of weeks ago, I refilled dozens of hand sanitizer dispensers. I saved this work for the end of the day, since I knew that there would be some vapour buildup, but after an hour I started to get a headache. I had forgotten to turn on the exhaust fan.

The next day the air quality was fine and so was I. I had experienced acute poisoning.

Chemical exposure comes from vapours, mists, gases, or airborne solids such as dust or fumes. In the safety biz, our definition of fumes is “fine solid aerosol particles which are suspended in air.” My headache from the hand sanitizer came from inhaling a high concentration of vapour within a short time. There are other exposure methods that I’ll discuss below.

Chemicals can affect you by “local effects” or by “poisoning.”

Local effects are what happens when the chemical contacts your body through your skin or eyes, or by breathing or ingesting it. The result is a rash, itching, or an allergic reaction on your skin; burning or itching eyes; or respiratory irritation and coughing. These happen when a chemical is in direct contact with the mucous membranes of your body.

Corrosive materials, which are either caustics or mineral acids, can cause the worst local effects, which are burns to the skin or eyes. When working with such chemicals, keep a bottle of drinking water handy so you can use it immediately to rinse your skin or eyes (then quickly go to a sink for more rinsing). If you get a chemical in your eyes, immediately rinse for at least 15 minutes and seek medical attention.

Acute poisoning like I referred to above happens when chemicals that contact your body are absorbed into your blood stream and then carried to various organs where they may do damage. A one-time exposure is known as acute poisoning. It took an hour for the concentration in my blood stream to build up, causing my headache.

The concentration of a chemical is what makes it poisonous (see also The Dose Makes the Poison by Patricia Frank and M. Alice Ottoboni). Hand sanitizer in your home gives off little vapour and is safe; I keep a small dispenser of it in my car. If I had refilled my dispensers outdoors, where the vapour would not concentrate, I would have been safe. This is why the instructions on cans of rust paints, insecticides, and the like say “for outdoor use only” or “use in a well-ventilated area.”

Chemicals for industrial use have regulations to identify them during transport and during use. This is not required for household chemicals. So whether at work or at home, always label the container. Never put a chemical in a drinking glass or beverage container.

To learn about the toxicity of any chemical you have in your home, Google the product name followed by “SDS” (which stands for “safety data sheet“).

All SDS sheets contain results from two tests: LD50 and LC50. These tests are usually done on rats or mice, and the results are given under “toxicological information” about acute exposure for each chemical in the product (many products contain more than one chemical).

The LD50 test is the amount of a product that is a lethal dose to 50% of the animals who ingest the product orally. The lower the number for the LD50, the higher the toxicity. It is measured in mg/kg of body weight, so you can also extrapolate the lethal dose for humans.

LC50 is a test for chemical concentration of vapours in the air. It stands for “lethal concentration 50%,” which is the concentration of a chemical (measured in mg per litre of air) that is needed to kill 50% of test animals. As above, the lower this number is, the more toxic the chemical. Around the home, fuels, paints, adhesives, and cleaning products offer your greatest risk of exposure.

Remember to always ask yourself “what can hurt me or what can hurt someone else?”

If you can keep the chemical away from yourself, you will be safe.

You generally risk chemical exposure in three ways at home.

  1. Skin contact from cleaners, solvents, paints, fuels, pesticides, etc. Burns or absorption through the skin or eyes are the most common means of chemical exposure. Your skin has protective layers of oils and fat that the solvents will dissolve, allowing the chemical to enter your bloodstream. Use gloves, safety eye protection (chemical goggles are best), and any other PPE that the product’s label or SDS sheet recommends.
  2. Inhalation of fumes, vapours, mists, gases, or dust. Protect yourself by doing the job outdoors, opening windows, and wearing PPE (a CSA approved respirator with chemical or dust filters, which seals to your face without any air leakage). Be careful about working in confined spaces with toxic gases, such as near septic tanks. This can be dangerous—leave it to professionals.
  3. Ingestion of foods contaminated by chemicals. Use good hygiene after using chemicals and keep food and drink out of the way while cleaning, painting, gardening, etc. As mentioned above, avoid using food containers (such as travel mugs) to mix or store any chemical.

Only use chemicals as directed. Even heating them can release toxins. Don’t combine chemicals such as cleaners. They may create a third chemical when combined, which could be extremely toxic.

One of my hobbies is oil painting. When I started, all painters used many toxic chemicals and unsafe practices, but today things have changed. Now I do my painting wearing rubber gloves, I don’t use chemicals such as turpentine, and I use little paint thinner. Many of the toxins in the paints, like the heavy metals cadmium and cobalt, which have long-term health effects, are now replaced with safer ones. There are even water-mixable oil paints now available.

If you do woodworking, wear a mask and use a dust extraction system when sanding. Check commonly used wood to see if it may harm you down the road. Dust from certain species such as western red cedar can affect you in the long term (“chronic poisoning”). There are even SDS sheets for each wood species.

And remember, the best toxic product in your home is the least toxic one. Consider your options before you buy, and safely dispose of any old chemicals still on hand. (This reminds me: I still have a container of pesticide in my garage that I’ll need to dispose of during the next hazardous chemical collection day.)

Halifax Magazine