In An Inspector Calls, what quotes relate to Eric being guilty for pushing Eva to suicide?

In the Inspector's final speech, he states, "We are responsible for each other." Every person has a duty to behave morally and carefully. In their carelessness, each of the Birlings has had a part to play in Eva's death, not least Eric.
Eric is first described to us as being in his early twenties, "half shy, half assertive." Gerald states that he has gathered that "he does drink pretty hard." These two quotations give valuable insight into Eric's character as an irresponsible, heavy-drinking young man and critical background into his treatment of Eva, whom it is revealed that he got pregnant. 
At the beginning of the Inspector's inquiry, Eric announces that he has a headache and that he had better go to bed. The Inspector stops him and says, "If you turn in, you might have to turn out again soon." From this we can gather that the Inspector has something to say to Eric and that his part in the death of Eva will be revealed.
Inadvertently, it is Mrs. Birling who condemns Eric for his part in Eva's death. She had refused Eva help as she was pregnant and unmarried and, rather than accepting her responsibility for this, she says, "Go and look for the father of the child. It's his responsibility." She carries on in this vein, declaring that the father ought to be "dealt with very severely" until Sheila realizes and tells her to stop.

"Look, Inspector, you're not trying to tell us that—that my boy—is mixed up in this—?"

Despite the fact that Eric certainly was the father of Eva's child, Mrs. Birling refuses to believe it. Eric enters, looking "pale and distressed," as the curtain falls on Act II.
It is worth noting that Eric's interview is the shortest in the play. Eric does not deny anything the Inspector says. He admits that he was "in that state when one easily turns nasty" and threatened to make a row until Eva let him in to her room. He admitted to returning to see her again and, when she told him she was pregnant, he says, "I was in a hell of a state about it."
In this instance, Eric is not completely careless. He cares for Eva, although he does not love her, and he takes fifty pounds from his father's office to try and help her. After fully realizing the horror of her death, he says, "I'm not likely to forget."
The Inspector responds:

"Just used her for the end of a stupid, drunken evening, as if she was an animal, a thing, not a person. No, you won't forget."

This quote from the Inspector sums up Eric's culpability. Even though he had some awareness of the consequences of his actions and later offered to help her, Eva meant nothing to him. He forced his way into her room and used her for his own selfish pleasure just because he could. Eric does learn from this, and he ultimately accepts his responsibility, but that acceptance does not erase the fact that he overlooked another person's humanity for his own pleasure.