A safety data sheet must be accessible to workers throughout the entire time a hazardous product is on site. Once a product leaves service, keep the SDS on file for 30 years from its last date of use. This article explains both requirements and what to do when a supplier sends a revised version.
How Long Must an SDS Be Kept According to WHMIS
Canadian employers face two separate obligations when it comes to SDSs. One applies while the product is on site. The other takes effect the day you stop using it. If a chemical is currently in your workplace, both obligations apply at the same time.
While the Chemical Is in Use
WHMIS and provincial OHS legislation both require employers to keep a current SDS on hand for every hazardous product in the workplace. Workers need to be able to get to it on any shift, with no barriers in the way.
"Accessible" means within reach during working hours. Not stored in a locked room, and not hidden behind a login. Paper binders are acceptable. So are digital systems, provided any worker can pull up any SDS right away, even if the network goes down.
If a worker asks for an SDS and you can't produce one, that's a violation of your provincial OHS legislation. There's no grace period.
After You Stop Using the Chemical
When a product leaves your workplace for good, the day-to-day access obligation ends. A longer-term one comes into effect.
Employee Exposure Record: Under the Canada OHS Regulations (SOR/86-304, s.10.6) for federally regulated workplaces, and equivalent provincial OHS legislation for most employers, an SDS qualifies as an exposure record. Those records must be kept for 30 years from the last date of use.
The 30-Year Clock: It starts on the last day any worker was exposed to the product. It doesn't reset when you remove the product from your facility or dispose of remaining stock.
What You Need to Keep: Holding onto the SDS itself satisfies the requirement. If keeping every SDS for decades isn't practical, a substitute record is permitted, provided it names the product, identifies where it was used, and covers the dates of use.
The Substitute Record Trap: A lot of workplaces take this route but fail to write down those details before discarding the original. Once the SDS is gone, rebuilding that information from scratch is rarely possible. The safer option is to keep the SDS.
What to Do When You Get an Updated SDS
Suppliers issue new versions when a product's formula changes or fresh hazard data comes to light. Getting a new SDS doesn't mean the old one can go straight in the bin.
- Compare the two versions. Look at whether the hazardous ingredients have changed between the old SDS and the new one.
- If the formula is the same, the new SDS takes over. You can discard the previous version with no 30-year obligation attached.
- If the formula changed, both versions need to stay on file. Each one covers a different window of worker exposure. Keep both for 30 years from the last date the original formula was in active use.
- Date every version you archive. The period it was in use is what makes it useful as a record later on. A stack of undated old SDSs won't help much when a regulator or a claims process comes calling.
- Don't discard on the same day the new version arrives. Move the old SDS into your archive the same day the new one goes into active use.
Who Keeps What Across the Supply Chain
Your role in the supply chain determines what you're responsible for keeping and for how long.
| Role | SDS Obligation | Retention Period |
|---|---|---|
| Employer (Chemical User) | Keep current SDS accessible while in use; archive when discontinued | 30 years from date of last use |
| Manufacturer | Write and maintain accurate SDSs; update within 90 days of new hazard data | Keep current; own worker records follow 30-year rule |
| Importer/Distributor | Supply current SDS to customers at point of sale; provide updates when available | 6 years under HPA s.14.3; must supply updated SDS at each sale |
One thing to watch: sell an imported product under your own Canadian label. The Hazardous Products Act treats you as the manufacturer. SDS authorship and keeping the underlying classification data become your responsibility.
Building a System That Handles Both Rules
Keeping SDS records in good order across their full life, from active use through a 30-year archive, takes some planning. Current sheets need to be within easy reach for workers. Archived sheets need safe, long-term storage that doesn't get mixed up with daily operations.
The step missed most often is noting the last-use date the same day a product comes out of service. Wait too long and the date is gone. Without it, you can't prove when the 30-year clock started. Your archive won't hold up if it's ever challenged. For larger inventories, a dedicated SDS management system handles version history and use-date tracking automatically. Cloud-backed storage means a single hardware failure won't wipe out years of records.
Two further points worth getting right early. If the business is sold, all exposure records transfer to the new owner. If it closes without a successor, you're responsible for notifying affected workers and ensuring records are appropriately transferred or preserved. File formats also shift over time, so schedule a review of your archived files every few years. A PDF from 2001 may not open reliably in 2031.
Final Thoughts
SDS retention under WHMIS has two parts. The first is having a current SDS available for every hazardous product currently on site. The second is holding onto records for 30 years from the last time each product was used.
Cross-check your chemical inventory against your SDS files this month. For products you've stopped using, confirm a last-use date is recorded and the SDS is in your archive. Where a supplier changed the formula at any point, you need both the old and new versions on file. Go through your discontinued product list and flag anything without a confirmed last-use date. That's where the gaps sit. And those are the ones that cause problems when a former worker files a health claim years later.
Frequently Asked Questions
Does the 30-year rule apply to products used only occasionally?
Yes. It applies to any product workers were exposed to, regardless of how often. Occasional use still creates a record-keeping obligation under WHMIS.
Can you store SDSs digitally to satisfy the 30-year requirement?
Yes. Provincial OHS regulators accept electronic records as long as workers can access them without delay. No login barriers during an inspection, and working terminals wherever workers are present.
What happens if your supplier closes and old SDSs are no longer available?
The obligation stays with you. Switch to the substitute record: write down the product name, where it was used, and the dates of use.
Do you need to keep the SDS for a product you received but never opened?
If no workers came into contact with it, the exposure record rule doesn't apply. The active-use obligation also falls away if the product was never put to use.
Does the 30-year rule still apply after a worker has left the company?
Yes. Retention follows the product, not the person. The clock runs from the last date of use regardless of when they left. The clock runs from the last date of use regardless of when the worker left the company.
Zarif Ahmed
An engineer and safety writer by profession, focusing on chemical management, regulatory development, and the patterns that shape workplace practice over time.