Absent T workers were to blame for the majority of the nearly 40,000 missing buses last year that left passengers waiting for rides that never came, a Herald review found.

All told last year, the T reported 39,937 “missed trips” on the transit agency’s 178 bus routes, according to the data.

Some of the largest number of those missed bus trips — and T employee absences — happened when there wasn’t a flake of snow on the ground. In August, the MBTA missed nearly 4,500 bus trips — mostly due to worker absences. Only 455 missed trips that month were due to unavailable or disabled buses.

The review also found that in February alone this year, nearly 7,500 missed trips left passengers stranded in the cold. MBTA officials at the time complained that mechanical failures led to systemwide shutdowns last winter, but the agency’s own records show that less than 9 percent of the 7,417 missed bus trips in February were attributed to disabled or unavailable buses.

The T’s data show that 72 percent of those missed trips were due to bus drivers who didn’t show up to work.

The Herald review comes as Gov. Charlie Baker is set to release a task force report that will recommend fixes for the beleaguered transit agency after a service collapse last winter.

“The special panel is reviewing all aspects of the MBTA’s operations, and the governor looks forward to reviewing their report in the coming weeks,” Baker spokesman Billy Pitman said.

The Herald reported last month that time off for all MBTA workers surged during the snowiest three-week period this winter. More than half of all T workers called in sick or took at least one day off between Jan. 27 and Feb. 16 — a 32 percent increase over the same 21-day period last year.

T attendance records obtained by the Herald showed the largest number of MBTA absences were during blizzards or the day after a major snowstorm, including Feb. 9. That Monday, 17 percent of all MBTA workers didn’t report to work after a weekend storm dumped nearly 2 feet of snow. The T was forced to suspend all rail service the following day.

The new bus records show that despite the more than 7,400 missed bus trips in February, MBTA officials still claimed drivers made more than 95 percent of scheduled trips — just slightly below the average 98 percent monthly success rate the agency claimed last year. Agency records show the number of MBTA bus trips scheduled each month has fluctuated up and down by as much as 24,000 trips.

MBTA spokesman Joe Pesaturo said the fluctuation in scheduled bus trips is due to holidays and the number of weekdays in a given month. He declined the Herald’s request yesterday to interview MBTA Interim General Manager Frank DePaola about the missed bus trips.

The transit agency ignored the Herald’s request earlier this month to review daily reports for missed trips from five MBTA garages — hubs for some of the busiest bus lines, including Route 1, which runs on Massachusetts Avenue.

The MBTA instead released a spreadsheet summary of missed bus trips by the month — without a breakdown by day or route line — only after the Herald opened a public records appeal with the Secretary of State’s Office on Monday.

Pesaturo said agency lawyers would charge the Herald to review and redact thousands of pages before releasing any daily reports detailing the number of missed trips and why.

“I am told the logs include specific information about employees and their reasons for being absent, which is protected under privacy laws,” Pesaturo said.

But a blank MBTA missed trips form provided to the Herald asks garage managers to identify drivers only by badge number and lists generic reasons for missed trips, such as “manpower,” “operator sick” and “traffic” — not specific medical information for named employees, which is protected under a public records law exemption.

Left Behind:

Absent T workers were responsible for the majority of the nearly 40,000 missed bus trips last year that left passengers waiting for rides, a Herald review found. Here are the total missed bus trips by month for all 178 MBTA bus routes:

2014

January 2,483

February 2,545.5

March 2,947.5

April 3,742

May 3,354.5

June 3,638.5

July 3,086.5

August 4,485.5

September 2,791

October 3,564.5

November 3,175.5

December 4,123

Total: 39,937

2015

January 2,452

February 7,417.5

March 4,340

Source: MBTA