If you are not using an SDS software package or SDS supplier who can assist you, start by figuring out what happened to the company. One resource that might work is the Internet Archive's Wayback Machine which preserves snapshots of web sites over the years.
However, you still need to document your company's use of that material under .1020, Access to Employee Exposure and Medical Records, and the SDS is normally the easiest way to do that.As far as the impact this has on an workplace where these obsolete chemicals are still in use and no (M)SDS was ever obtained, we have been hard-pressed to find an actual OSHA interpretation.Our best guess is that they would require you to make a documented "good faith" effort to locate a sheet, starting with the manufacturer (see OSHA Field Operations Manual CPL CPL02-00-159 for more about good faith). Securities and Exchange Commission keeps records of publicly-traded companies, mergers and acquisitions, so you might try there as well.That really depends on how SDS's are handled at your organization.If your employer uses a software program or Internet subscription service for SDS's then maybe not (check with your supervisor, the answer depends on what state and federal agencies have jurisdiction, see also the section on paperless compliance below.).A "harmless" chemical may later be found to cause cancer or other disease sometime in the future (asbestos is one good example).