The Canyon of Heroes will come alive for the first time in two years Wednesday at a ticker-tape parade to honor the city’s front-line workers who helped fight the COVID-19 pandemic. 

But the heat is forcing some changes to the event that is expected to draw thousands of participants to the march, which will feature 14 floats representing 260 different sectors of essential workers.

Temperatures are forecast to be in the low 90s Wednesday with a heat advisory.

“We have a little bit of a challenge because we do have some heat tomorrow in terms of timing of this parade,” Mayor Bill de Blasio said at a news conference Tuesday. “It’s something we have to work with, and we are going to make some changes to keep people safe.”

The city will be adding more cooling and water stations along the route, and a ceremony planned at City Hall will now be canceled, City Hall officials said.

“The parade itself will be the central salute to our heroes,” the mayor said.

While past ticker-tape parades have featured a large number of spectators, the mayor said he doesn’t expect this parade to draw as large a crowd. 

“I think it's going to be a healthy attendance, but I don’t think it's necessarily going to be the traditionally huge attendance,” he said, citing the lack of people back at work in offices along Broadway. 

The sectors that will be represented in the parade include hospitals, transportation, education, childcare, utilities, advocacy groups and delivery and funeral services. 

But some first responder groups including Local 2507, the union that represents EMTs, paramedics and fire inspectors, say they are boycotting the parade because of working conditions and pay. EMTs have been working without a contract for three years. 

“We believe New York’s brave essential workers should be recognized in a meaningful way, but the public display from the de Blasio administration is all optics and no substance,” said Oren Barzilay, president of Local 2507, in a statement. “A parade does not bring this workforce out of the poverty wages they are now being paid. It is far past time that the city gives this workforce the respect they deserve in livable wages. If taxpayer dollars can be allocated to put on this parade, then Mayor de Blasio, you can easily find the means to financially support our FDNY EMT’s, Paramedics and Fire Inspectors. We consider anyone participating in this parade to be crossing a picket line.”

In response, the mayor's office encouraged everyone from the city to participate in the parade. 

“Negotiations with the union are ongoing and we’re looking forward to a fair outcome," Mitch Schwartz, a spokesman for Mayor de Blasio, said. "We urge all New Yorkers to join us in honoring the frontline heroes who did so much to fight back COVID-19.”

The parade kicks off at 11 a.m. from Battery Park and proceeds north through the Canyon of Heroes, the section of lower Broadway through the Financial District with embedded granite plaques on the sidewalks honoring past parades.

Sandra Lindsay, the first American to receive the Pfizer vaccine in December and a nurse from Queens, will serve as grand marshal of the event.

Both vaccinated and unvaccinated people are encouraged to attend, although the mayor advised unvaccinated people to wear masks and practice social distancing.

“Everything’s a little different because people are still not used to going out to big events, but we really encourage people to come out and salute these amazing health care heroes and essential workers who really deserve all the thanks we can give them,” de Blasio said.