March 2, 2019, is the deadline for electronically reporting your OSHA form 300A data for calendar year 2018. Collection began January 2, 2019.
Special note for establishments with 250 or more employees: Under the current recordkeeping rule, the initial deadline for electronic submission of information from OSHA Forms 300 and 301 by covered establishments with 250 or more employees was July 1, 2018. However, OSHA has published a Notice of Proposed Rulemaking (NPRM) to amend its recordkeeping regulation to remove the requirement to electronically submit to OSHA information from the OSHA Form 300 (Log of Work-Related Injuries and Illnesses) and OSHA Form 301 (Injury and Illness Incident Report) for establishments with 250 or more employees which are required to routinely keep injury and illness records. OSHA will not enforce this deadline for these two forms without further notice while this rulemaking is underway.
More here. 1/14/2019