Wisconsin- A 33-year-old Grafton woman was fighting for her life Thursday night after she drank concentrated drain cleaner given to her by a man who then videotaped her violent vomiting for his sexual gratification, Milwaukee police said.

With just two gulps, the caustic solution seared a path from the woman’s lips down to her stomach, burning holes along the way and then likely scorched her again as she vomited the poison.

The woman, who was not identified, was at St. Michael Hospital, according to one of the victim’s co-workers. Police said she might die.

Detectives are studying a videotape that shows the woman drinking the solution and then throwing up. Police said the tape shows at least three other women drinking solutions and becoming ill.

On Tuesday, police arrested Sean A. Kobin, 20, of Mequon, near the former Northridge Mall on suspicion of first-degree recklessly endangering safety, according to arrest records.

A registered sex offender in Wisconsin, Kobin was convicted last year of exposing a 13-year-old girl to harmful materials by urging her, in a series of phone calls and computer messages, to drink bleach, lighter fluid and urine to arose him sexually, according to a Waukesha County criminal complaint.

Kobin was released from prison April 19 after serving a year. He is on probation and was being held late Thursday in the Milwaukee police jail.

A man who answered the phone at the Farmdale Road home where Kobin lives has declined to comment. Kobin met the victim at Fantasy Gifts, an adult store at 8340 W. Brown Deer Road, where she worked, police said. At 10 a.m. Tuesday morning, Kobin and the woman – described by police as “acquaintances” – were in a parking lot. Kobin gave her $20 to drink the solution, police sources said.

Before drinking it, the woman asked Kobin whether it would hurt her and he said it wouldn’t, sources said.

After the woman became violently ill, Kobin called 911, police said. She was rushed to the hospital, and he was arrested.

Capt. Michael Young called the episode “twisted.” He and others at the Milwaukee Police Department, who deal with cases such as these on a regular basis, said they were not familiar with Kobin’s alleged fetish.

“This is so awful,” said Anne E. Schwartz, department spokeswoman. “We don’t want to say anything that will compromise the investigation in any way.”

Police sources said the woman drank sodium hydroxide, which is found in drain cleaner, but in a much higher concentration than found in products for household use.

Such severe poisonings are rare, according to Mary Powers, a registered nurse at the Wisconsin Poison Center. People who ingest drain cleaner are urged not to vomit, she said.

“You can get burns going down, and it can burn coming back up again,” Powers said.

Patients are urged to call the poison center and get immediate medical attention. She said in a case such as one involving the Grafton woman that doctors likely would use intravenous feeding to let the esophagus and stomach heal by keeping away water and food. Infection would be another risk, prompting doctors to likely give her antibiotics, Power said. She also might have needed blood transfusions.

To repairs holes in the stomach and elsewhere, doctors might have to perform surgery, essentially stitching together what parts of the undamaged material that remain, Powers said.

In rare cases, drinking the drain cleaning solution, which is a base, can be deadly, she said. Base burns are much more damaging to human tissues than those caused by acids, causing an effect known as “liquefying necrosis,” Powers said.

“It gets into the tissues and melts the tissues,” Powers said. “It is a chemical burn. Because it is a base, is gets into the tissues much deeper.”Communicated with teen girl

In June 2003, Kobin was arrested after police learned he communicated with a 13-year-old girl, urging her to perform dangerous acts for his sexual gratification.

According to the criminal complaint:

Kobin, who met the girl through her older sister, dared her over the phone to drink bleach, which she did. She began shaking and hung up the phone. Kobin told her later that night that her “immune system would skyrocket as a result of her drinking bleach.”

On other occasions, Kobin dared the girl to drink other dangerous substances and cut herself, but she did not.

Kobin was convicted of two counts of exposing a child to harmful materials, a felony. He received a year in prison and 2 1/2 years of probation. He also was convicted of misdemeanor theft in Ozaukee County in 2003 and placed on 18 months’ probation, according to online court records.

Since his release from prison, Kobin has not been found in violation of his probation, said John Dipko, spokesman for the state Department of Corrections. Kobin was monitored without incident by an electronic bracelet from April until Sept. 15 and met with his probation agent every week since his release, Dipko said.

Kobin works the third shift at a business in Mequon making CDs and DVDs, Dipko said.