HARRISBURG — Legislation that would overhaul the operating standards for abortion clinics in Pennsylvania cleared a first crucial vote in the state Senate on Wednesday after a tense, sometimes angry debate over whether the proposal would improve women’s health care or force clinics to close in a back-door attempt to outlaw abortion.

The bill, which remains in the Senate, is a response to a now-shuttered abortion clinic in Philadelphia that prosecutors called a “house of horrors” after authorities found allegedly filthy and unsafe conditions and an alleged trail of misconduct so gruesome that the operator was charged with eight counts of murder.

A final vote on the bill is expected next week, and Democrats say they are not done proposing amendments to it.

The underlying bill sponsored by Senate Public Health and Welfare Committee Chairwoman Pat Vance, R-Cumberland, was designed to strengthen licensing standards and inspection requirements for abortion clinics. There are 22 currently.

However, Sen. Bob Mensch, R-Montgomery, proposed an amendment that would require clinics performing abortions on women after nine weeks of pregnancy to meet the same standards as freestanding outpatient surgery centers.

It passed, 31-19, after senators voted 29-20 to defeat an attempt by Vance to push back the requirement in Mensch’s amendment to 14 weeks, instead of nine.