CHICAGO (CBS) — The Chicago Cubs apologized to fans Monday morning after extremely long lines for restrooms on Opening Night left many people venting their frustrations on social media.

Many regulars at Wrigley Field said they’ve never seen lines for restrooms as long as those Sunday night, with some sections of the concourse impassable, as hundreds waited in line.

Cubs spokesman Julian Green acknowledged the team was unprepared after two upper-deck restrooms were left out of order.

“Opening Day at Wrigley Field has always brought challenges with wait times and tonight was particularly extreme. Two bathrooms in the upper deck went down temporarily forcing fans downstairs where we already were experiencing issues with long wait times,” Green said in an email. “With 35,000 fans showing up in the ballpark tonight, we were simply not prepared to handle guests during peak periods. We have high standards for service and we missed the mark tonight.”

Some fans complained of missing up to two innings of the game and waiting as long as 45 minutes in line.

Large sections of Wrigley Field are still under construction, as the Cubs finish work renovating the bleachers in the outfield and other areas in the stadium. Even before the game started, it was clear not all restrooms at the stadium were ready for use. In at least one spot on the concourse, the Cubs had painted a large sign on a wall, reading “Future Home Of Better Restrooms (Relieved?)”

When those new restrooms do open, it certainly will be a big relief for fans, as many reported seeing people peeing into plastic cups or simply relieving themselves on the nearest wall.

Work on the bleachers was behind schedule, with the left field and center field bleachers delayed until May 11 and the right-field bleachers delayed until mid-June.

Green said the Cubs plan to add more portable toilets moving forward and will continue to monitor wait times for restrooms during the season.