A firefighter from Norristown, Robert Myers, was eventually lowered into the tank on a rope and rappelled 60 feet to ground level with Martinez.
Martinez was taken to Paoli Hospital after his 31/2-hour ordeal but was not admitted, officials said.
Montgomery County Coroner Walter I. Hofman said Thursday that Schmidt died after suffering "multiple injuries" in the fall and ruled his death an accident. A third worker was uninjured.
They were employed by Corrosion Control Corp., a Salem County, N.J., firm where Schmidt had worked for 14 years, following in his father's footsteps.
On Thursday, Thomas said Schmidt's family was reeling. Schmidt and his wife, Amy, had a 2-year-old son, plus responsibility for five other children from previous relationships.
Thomas said she had known the Schmidts for several years. Her son, she said, once was engaged to marry Amy, but he was killed in a car accident 11 years ago. The two women have remained close.
She said she loved Jason Schmidt "like a son."
"I lost a son and worried about who Amy would marry, if they were going to be good to my grandkids. I never had to worry about that with Jason," she said.
Schmidt enjoyed simple pleasures, Thomas said - playing with his children, riding his motorcycle, "being a goofball." He grew up in New Jersey but later moved to Pennsylvania, and he and his wife had met at a Ruby Tuesday's where she was working five years ago.
"It's rough," Thomas said. "It'll definitely be a void in our life without Jason in it."
Answers on what exactly went wrong were still wanting the day after the accident. The Occupational Safety and Health Administration was investigating, Hofman said. Corrosion Control representatives did not return calls for comment.
The company has been inspected by OSHA three times before. Two inspections, which took place in Harrisburg, were routine but one found "scaffold fall protection violations," according to OSHA.
In 2008, OSHA investigated a workplace fatality involving Corrosion Control in Philadelphia. The company ended up paying $12,810 in fines.
Lower Providence officials said they believed that in Wednesday's incident, the workers' equipment malfunctioned, but would not elaborate.
Contact Aubrey Whelan at 610-313-8112 or firstname.lastname@example.org, or follow @aubreyjwhelan on Twitter.
Inquirer staff writer Carolyn Davis contributed to this article.