The 'Mean Girls' star had a health scare after she was reportedly found passed out in her California hotel suite. Lohan, 25, had later explained she was simply exhausted after "working 85 hours in 4 days" on her comeback movie 'Liz & Dick'
Two other crew members allegedly left the production due to exhaustion, and now bosses at International Alliance of Theatrical Stage Employees (IATSE) and SAG-AFTRA have launched a probe.
"The IATSE is on top of the situation on the set of Lifetime's 'Liz and Dick'. We have had union representatives on the set since last Friday and will continue to monitor the hours and working conditions there.
"We take very seriously the safety and wellbeing of our crews, and are dedicated to seeing that they are protected from hazardous working conditions," said Mike Miller, IATSE division director.
Meanwhile, a SAG-AFTRA spokeswoman said, "We have thoroughly investigated this matter and our business representatives have visited, and will continue to visit, the set of Liz & Dick.
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."