Solid and hazardous waste firm Clean Harbors Inc. reported higher net earnings but slightly lower revenue for its second quarter.

For the period ended June 30, the Norwell, Mass.-based Clean Harbors said its net income increased 25.3 percent to $28.7 million, or 47 cents per diluted share, compared with $22.9 million, or 38 cents per diluted share, in the year-ago period.

Revenue slipped 0.2 percent for the quarter to $858.5 million from $860.5 million in the same period in 2013, according to a news release.

For the first half, Clean Harbors’ net earnings climbed 12.7 percent to $37.6 million, or 62 cents per diluted share, compared with $33.4 million, or 55 cents per diluted share, a year earlier.

Revenue declined 1 percent to $1.71 billion from $1.72 billion.

“We rebounded from a slow start to the year and moved into what is historically a seasonally stronger period for the company,” said Alan McKim, chairman and CEO. “Our top-line results were slightly below our guidance range, hampered by some project delays and reduced activity in the oil sands region as well as a larger-than-expected revenue decrease in Oil and Gas Field Services.”

McKim said the company expects its results for the year to conclude at the low end of its revenue guidance, because of softness in certain markets such as oil sands.