Bexar County elections officials are working to prevent large numbers of mail-in ballots from being rejected in the upcoming election, as they were in last month's primary. Every mail-in ballot is accompanied by instructions reminding the voter about a new ID number requirement that many voters failed to follow last time. The March 1st primary was the first election conducted under the new state voting law, Senate Bill 1. Nearly 22-percent of mail-in ballots were rejected in Bexar County. Early voting in the May 7th election started Monday.