The utility that owns a steam pipe that exploded in midtown Manhattan last summer sued the city and a company hired to fix leaks in the pipe, saying improperly injected sealant and water from nearby sewer and pipelines contributed to the blast.

Consolidated Edison Corp. has already been named in more than 40 lawsuits following the July 18 explosion near Grand Central Terminal. A woman died of a heart attack and dozens of people were injured when the 83-year-old pipe ruptured, spewing a geyser of steam and mud that flung rock, asphalt, and concrete into the busy street.

State utility regulators found earlier this year that Con Ed wasn’t managing its underground steam system properly before the explosion. But in the complaint filed Wednesday in Manhattan’s state Supreme Court, the utility said that Texas-based Team Industrial Services Inc. mistakenly injected its sealant into the steam system while repairing leaks to the pipe.

Before the date of the explosion, “the two steam traps servicing the steam main became clogged with a foreign substance introduced into the steam system by Team,” the lawsuit said.