Workers in modern industrial workplaces are exposed to myriad toxic chemicals. In an effort to inform employees and persons in the community about the risks of toxic chemicals in the workplace, OSHA requires that employers make material safety data sheets (MSDSs) available to employees, medical care providers, local fire departments, and other community organizations with an interest in toxic exposures. Physicians who practice occupational medicine or emergency medicine should be familiar with the MSDS and how to use it.

MSDSs are the starting point for determining if an employee has been exposed to a toxic substance. Occupational medicine physicians should obtain appropriate MSDSs from each employer for whom they provide occupational medical services. MSDSs can also be useful for general medicine physicians who suspect that a patient is suffering from an occupational exposure. The regulations require that the MSDS be in English, that it contain specific information on the contents and hazards of the product, that it provide information on emergency treatment, and that it list information for contacting the manufacturer.

There are several important limitations that may make the data on MSDS misleading. Within certain limitations, the manufacturer is not required to perform toxicity testing on the mixture or its constituents. The MSDS need only be based on a review of the literature. Even this review is subject to question because there are no standards to define an adequate search or to resolve conflicting research reports. It is not unusual to find manufacturers of the same chemical list different health risks on their MSDS. In addition, manufacturers sometimes ignore chemicals that they use as vehicles but do not manufacture themselves. Although these are generically described as inert ingredients, they sometimes include highly toxic aromatic hydrocarbons or complex organic resins.

If the MSDS does not provide enough information, either because trade secret information has been left out or because the physician suspects that an ingredient is toxic, the physician can obtain more detailed information directly from the manufacturer identified on the MSDS. This may require several inquiries, however, because only the original manufacturer of the substance is responsible for keeping full information on health hazards. Thus the physician may need to call the manufacturer of each substance that has been mixed into a product.