How to Make Sense of Material Safety Data


Material Safety Data Sheets must be available to employees and they must be trained to read them. Failure to abide by this rule set by the U.S. Occupational Safety and Hazard Agency is the second-most frequent employer violation. Even when MSDSs are available, few employees ever read them. Culturally, we believe instructions and warnings are a joke. Well, its your funeral … literally.


Available for any product containing hazardous ingredients, the MSDS (now known by the international SDS, or Safety Data Sheet) is your roadmap to safe use and to the physical and environmental characteristics of the product. There are many training guides on using these sheets ( is some general guidance on how to read between the lines.

If the composition is a trade secret (section 3) and basic physical properties (section 9) are not determined, don’t buy the product. The manufacture is not taking disclosure seriously. There can be logical exceptions, but in these cases they should say not applicable rather than not available.

Section 2: Hazards Identification. Read this in detail-although you may assume this information will be repeated in other sections, often it is not. For example, something can cause reproductive problems may not technically be considered toxic.

Section 3: Chemicals. You are going to need to look these up. In the example of a cleaner, some may be obvious; sodium carbonate is washing soda, and sodium citrate is simply neutralized citric acid, which is extracted from citrus fruits. Look for manufacturer SDS for ALL of the key ingredients; these SDS tend to be more clearly state the hazard.

Section 5. Fire Fighting. The flash point (the temperature above which there will be enough vapors in a confined space to explode) is one of the most accessible hints to relative ignitability. This may also be listed in section 9.

Section 9: Physical Properties.Excessive blanks here mean they arent trying or are being purposefully evasive. Errors are also too common. Kleen Strip Premium list the evaporation rate as

Section 12: Ecological Information. It is unacceptable for a company to claim a product is safe or green, and then not complete this section. If they can’t prove it, they shouldnt make the claim. Look for toxicity to marine organisms and quantitative statements about biodegradability. If nothing is listed, look up the SDS for key ingredients. For example, Soy Strip-which claims it is green- leaves the marine toxicity section blank. Meanwhile, the SDS for its main ingredient (NMP) is about 10-20 times more toxic than propylene glycol antifreeze.

For reference, LC/50 or EC/50 means 50 percent of hatchlings will die at the referenced concentration within the test period (48 or 72 hours). Soy Strip reports the following toxicity (daphnia are a water flea; the SDS should have listed the kind of fish).

Toxicity to Fish LC50 > 500 mg/l

EC50/48h/daphnia = > 1000 mg/l

EC50/72h/algae = > 500 mg/l

Section 13: Disposal Considerations. Most of the time the sheets say Follow local regulations, which is little help. For example, several producers of methyethylene chloride say follow local regulations, even though it is an EPA listed hazardous waste (F002) and will always be a hazardous waste, even after the waste is dry. Materials that are almost certainly non-hazardous can become contaminated in use. To be non-hazardous the pH after use must be 2-12.5, flash point above 140F, and it cannot contain certain listed or toxic materials. Liquids cannot go in the trash. Can it be recycled? Does it meet sewer requirements (read local sewer ordinance, available on-line). This EPA guidance explains hazardous waste determination.

Yes, the numbers and Latin names can be off-putting, but learning to read an MSDS is just as important as learning to read the ingredients on a frozen dinner.

Darrell Nicholson
Practical Sailor has been independently testing and reporting on sailboats and sailing gear for more than 50 years. Supported entirely by subscribers, Practical Sailor accepts no advertising. Its independent tests are carried out by experienced sailors and marine industry professionals dedicated to providing objective evaluation and reporting about boats, gear, and the skills required to cross oceans. Practical Sailor is edited by Darrell Nicholson, a long-time liveaboard sailor and trans-Pacific cruiser who has been director of Belvoir Media Group's marine division since 2005. He holds a U.S. Coast Guard 100-ton Master license, has logged tens of thousands of miles in three oceans, and has skippered everything from pilot boats to day charter cats. His weekly blog Inside Practical Sailor offers an inside look at current research and gear tests at Practical Sailor, while his award-winning column,"Rhumb Lines," tracks boating trends and reflects upon the sailing life. He sails a Sparkman & Stephens-designed Yankee 30 out of St. Petersburg, Florida. You can reach him at