Knovel (http://hdl.library.upenn.edu/1017/6967) is a set of online monographs and reference books in many areas of science and engineering. It can be used early in the research process to become aware of general safety information for particular activities, processes, and substances, as well as later in research to learn more specifics about substances.
There are several ways that you can find health, safety, and hazards information using Knovel.
CAMEO Chemicals (http://https://cameochemicals.noaa.gov/) is a free tool available from NOAA and the EPA that allows users to access the safety risks and hazards associated with specific chemicals and classes of chemicals, as well as predict reactivity between them. You can use CAMEO Chemicals online (https://cameochemicals.noaa.gov/), you can use its mobile site (https://m.cameochemicals.noaa.gov/), and you can also download the database for off-line use (http://response.restoration.noaa.gov/cameochemicals). There is also an app for tablets and mobile phones.
The help files within CAMEO Chemicals are very nice (https://cameochemicals.noaa.gov/help/cameo_chemicals_help.htm#t=1_home%2Fcameo_chemicals.htm), particularly the one about how to use physical clues to determine the identity of an unknown substance and how to search CAMEO Chemicals for that substance (https://cameochemicals.noaa.gov/help/cameo_chemicals_help.htm#t=3_searches%2Fusing_physical_clues.htm).
The ACS Committee on Chemical Safety has a mission to "promote and facilitate safe practices in chemical activities," giving "advice and counsel to ensure safety by calling attention to potential hazards and stimulating education in safe chemical practices" (https://www.acs.org/content/acs/en/about/governance/committees/chemicalsafety.html, accessed August 26, 2016). They have a wealth of information available on their Web site. Some of the more generally applicable tools are linked below.