A key concept in OSHA's requirements for hazardous materials is that the employee has a “right to know.” This means your employer must provide you with information about hazardous materials you may work near or with. One way employers accomplish this is though “hazmat” (hazardous materials) training specific to a given job and often tailored to the specific hazardous materials that may be encountered. Notice we have used the word “may” twice now, rather than saying “probably will.”
In your hazmat training, your employer should identify another way of informing you. That's through the use of container labels and material safety data sheets (MSDS). This is a self-serve method, meaning it's your responsibility to read those labels and MSDSs. Follow up accordingly, and ask your supervisor for help or clarification if needed.