The state has tripled its complement of active gas line inspectors and hired eight new public utilities engineers since the disastrous explosions and fires in the Merrimack Valley nearly one year ago.

U.S. Department of Transportation officials last year warned the Baker administration that the state didn't have enough gas pipeline inspectors on the job just one month before faulty gas lines caused explosions and fires in North Andover, Andover and Lawrence.

At the time of the explosions, the state Department of Public Utilities had only eight engineers working on public utilities and only two of them were trained and available to conduct full inspections on gas pipelines.

In the year since the disaster, the state has brought on eight more engineers. Six current engineers are trained inspectors and seven more are on track for certification in the near future, according to a spokesperson from the Executive Office of Energy and Environmental Affairs.

The state's Energy and Environmental Affairs office says three engineers were hired in September and the state has listed open positions for four more. When all the hires are made, the state hopes to have 20 public utility engineers trained to inspect gas lines, double the average number of active engineers over the last decade.

DPU's public utility engineers conduct hundreds of announced and unannounced on-site audits annually and review safety protocols and procedures, according to EEA. Special certification is required to conduct official inspections of gas lines.

The department had brought on two new engineers in August and September 2018, just before the explosions. After the incident, DPU hired three engineers in December 2018, one in January 2019, one in February 2019 and three will join the ranks in September 2019.

Last year's group of eight engineers with only two active inspectors matched the lowest staffing numbers the department has seen in recent years. The state had ten engineers in 2017, an average of 12.5 in 2016, 11.5 in 2015, 12 in 2014, eight in 2013 and eight in 2012.