MONTPELIER — A bill that would set drinking water standards for five PFAS compounds and require water system managers to test for them by the end of this year has cleared the Legislature.

The governor is expected to sign the bill when it arrives on his desk.

The bill, SB 49, requires managers of public water supplies to test to ensure levels of five PFAS contaminants — PFOA, PFOS, PFHxS, PFHpA and PFNA — are below a combined 20 parts per trillion.

If elevated levels are found, drinking supply managers would have to treat water to lower levels and provide residents with clean drinking water until the public supply is safe.

The bill also requires the secretary of the Agency of Natural Resources to file a final rule for drinking water standards for the five PFAS compounds by February. Vermont’s Agency of Natural Resources has already proposed drinking water standards of 20 parts trillion combined for five PFAS compounds.

Under SB 49, ANR would have to devise a plan this year for a statewide investigation into potential sources of PFAS contamination and submit a report on managing landfill leachate. Next year, it would have to start setting drinking water standards for the thousands of chemicals in the PFAS family.

The Senate passed SB 49, earlier this session, but had to weigh in on changes proposed by the House. On Friday, the upper chamber agreed to the House’s changes, which Bray referred to as mainly “linguistic” in nature.

But a couple of changes were more substantive, he said. Under the Senate version, managers of public drinking water supplies would have to provide bottled water to residents if testing showed drinking water supplies had elevated levels of PFAS.

“It turns out that’s not the standard protocol for municipal water systems,” said Bray. In the House’s proposal that was agreed to, water suppliers would issue “do not drink notices” to residents.

PFAS, or per- and polyfluoroalkyl substances, do not break down in the environment and are used in a wide array of manufactured products, from rain jackets to cookware to firefighting foam. Scientists have linked certain PFAS chemicals to testicular cancer, kidney cancer, thyroid disease and immune system affects, among other medical conditions.

PFAS gained notoriety in Vermont in 2016 after the state discovered that a particularly toxic chemical in that group, PFOA, had contaminated hundreds of wells in Bennington. State officials say the primary source of pollution was emissions from now defunct ChemFab Corp. plants in North Bennington.

The state’s Agency of Natural Resources listed those compounds as hazardous materials and adopted an emergency enforcement standard for groundwater — meaning companies that are found to have contaminated groundwater with those five chemicals would have to clean up the site.

Earlier this month, the state reached a settlement with Saint-Gobain Performance Plastics, which purchased ChemFab, to pay for municipal water line extension for residents with contamination wells.

Meanwhile, Bennington residents are moving ahead with a lawsuit seeking to make Saint-Gobain pay for property damages and long-term medical monitoring.

The federal Environmental Protection Agency has been slow to act to regulate PFAS, leaving states largely on their own to figure out how to deal with contamination. Both the EPA and the White House sought to block release last summer of a federal health study on PFAS contamination, fearing it would cause a “public relations nightmare.”

The EPA released a long-awaited draft plan this week for addressing groundwater contamination, which the New York Times reports was “significantly weakened” after pressure from the Defense Department. The military long-used PFAS-related fire fighting foam, which is known or suspected to have contaminated hundreds of sites around the country.

Six other states — Alaska, California, Minnesota, New Hampshire, New Jersey and New York — have policies or are developing policies that would be stricter than the EPA’s 70 parts per trillion health advisory for PFOA and PFOS, according to E&E News.

Rebecca Kelley, spokesperson for Gov. Phil Scott, said in an email last week that the administration has been working closely with lawmakers throughout the session on SB 49. She said Scott will review final changes when the bill gets to his desk.

“I think we’re getting very close on that one,” Scott said of SB 49 during a press conference Thursday.