Employment among construction workers increased in 30 states during January and February, and 19 states added construction jobs, the Associated General Contractors of America reported.

While the Labor Department data was good news, the association warned that it was too soon to say whether this was a seasonal trend or the start of a sustained recovery.

“These are certainly some of the best state-by-state numbers the industry has seen in quite some time,” said Ken Simonson, the association’s chief economist. “But it is too early to tell whether this is the start of a positive trend or the rebound that comes with a February thaw.”

The AGC said Washington, D.C., had the largest one-month percentage increase in employment (5.8 percent, 600 jobs), followed by Connecticut (4.2 percent, 2,100 jobs); Georgia (3.7 percent, 5,000 jobs); and Oregon (2.9 percent, 2,000 jobs). California (15,500 jobs, 2.7 percent) added the most construction jobs between January and February, followed by Georgia; North Carolina (4,500 jobs, 2.7 percent); and Florida (4,400 jobs, 1.3 percent).

Simonson added that 18 states lost construction jobs in the first two months of 2011 while employment was unchanged in three states.