Los Angeles (CNN) -- Lindsay Lohan's complaint that working long hours caused her to collapse from exhaustion triggered union investigations of the "Liz & Dick" production, two unions said.
Producers called paramedics to the Ritz-Carlton Hotel in Marina del Rey, California, after Lohan was unresponsive to knocks on her door Friday morning.
Lohan, 25, was simply sleeping after working "a grueling schedule the past few days," publicist Steve Honig said Friday. She is in the middle of filming the Lifetime movie in which she portrays legendary actress Elizabeth Taylor.
Lohan later posted a Twitter message that led to the union set visits:
"Note to self.. After working 85 hours in 4 days, and being up all night shooting, be very aware that you might pass out from exhaustion & 7 paramedics MIGHT show up @ your door.... Hopefully theyre cute. Otherwise it would be a real let down."
Union contract rules limit the number of hours actors and crew members can work on a movie or television production.
Both SAG-AFTRA, which represents actors, and IATSE, the stage workers union, confirmed they visited the set of the Lifetime Network movie
"We have thoroughly investigated this matter and our business representatives have visited, and will continue to visit, the set of Liz & Dick," SAG-AFTRA said in a statement late Wednesday. "We have spoken with representatives from the company and they are fully aware of their contractual obligations. We will ensure that all applicable penalties will be paid."
Reports that two hairstylists became ill from exhaustion last week led to the stage workers union to investigate.
"The IATSE is on top of the situation on the set of Lifetime's 'Liz and Dick,' " IATSE Director Mike Miller said. "We have had union representatives on the set since last Friday and will continue to monitor the hours and working conditions there."
The movie's producers did not immediately respond to requests for comment Thursday.
Production was delayed when Lohan was involved in a car crash on the way to the set two weeks ago.